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2,2-Disubstituted 2,5-dihydro-4-methyloxazoles (1) were synthesized from 2-aminopropanol in three steps. 3-Oxazolines 1 can be converted into various α-sulfinyl ketimines such as (SS)-{(4-methylphenyl)sulfinylmethyl}-2,2-diethyl-2,5-dihydrooxazole (5) which was stereoselectively reduced with Dibal-H to give 3-hydroxy-2-aminopropyl sulfoxide 7.

(SR)-(−)-N-[1-(Triethoxymethyl)ethylidene]-p-toluenesulfinamide (2) was synthesized from the addition reaction of triethoxyacetonitrile with MeLi followed by (+)-(R)-d-menthyl p-toluenesulfinate (1R). Sulfinimine 2 underwent complete stereoselective reduction with 9-BBN and addition reaction with allylmagnesium bromide. Optically pure α-amino acids were synthesized from these adducts by simple hydrolysis.

A remarkable asymmetric induction was observed in the one-pot condensation reaction of (S)-(-)-perillaldehyde with 4-hydroxy-6-methyl-2-pyrone in the presence of L-proline which provided the title compound, C 16 H 18 O 3 , a tricyclic pyrone, as a single diastereomer in 78% yield. As the configuration of the cyclohexane C atom holding the isopropenyl group is the same as that in the (S)-aldehyde substrate, the total absolute stereochemistry could be elucidated from its X-ray structure. The cyclohexane ring has a chair conformation in which the juncture H atom (H5a) is axially oriented and the isopropenyl substituent is equatorial.

Enantiopure 1 -t- butylsulfinyl-2-subsituted ferrocenes were synthesized in reactions of (SR,1S,2R)-1-t-butylsulfinyl-2-lithioferrocene (11) with various electrophiles in good yields. (SR,1S,2R)-1-t-Butylsulfinyl-2-formylferrocene (19), prepared this way, underwent complete stereoselective addition reactions with Grignard reagents under chelation controlled conditions with titanium tetraisopropoxide. 1,4-Addition reactions of selected α,β-unsaturated esters with cuprate reagents gave mixtures of two diastereomers. The lack of stereoselectivity in these 1,4-addition reactions is due presumably to the remote reactive site (C-3′) and the flexibility of the side chain of the ester. A stereoselective cationic displacement reaction of (1S,2R,1′S)-1-(t-butylsulfonyl)-2-[α-(2-propenoyl)oxybenzyl]ferrocene (44) with 1-acetoxy-1,3-butadiene was found to produce (1S,2R,1′S)-1-(t-butylsulfonyl)-2-(5′-oxo-1′-phenyl-3′-pentenyl)ferrocene (45).

Substituted quinolines (PQ code number), which reduce colony formation and increase gap junctional intercellular communication, were tested for their ability to interact with various molecular targets in murine and human tumor cell lines in vitro. Various markers of tumor cell metabolism, DNA fragmentation, mitotic disruption, apoptosis induction and growth factor receptor signaling pathways were assayed in vitro to evaluate drug cytotoxicity. Based on its ability to inhibit the metabolic activity of suspension cultures of leukemic L1210 cells at days 2 and 4 in vitro, PQ1 succinic acid salt is the most effective antiproliferative agent among the synthetic quinoline analogs tested. Moreover, antiproliferative PQ1 is effective across a spectrum of monolayer cultures of pancreatic Pan02, epidermoid A-431 and mammary SK-BR-3 and BT-474 tumor cells. PQ1 also blocks Ki-67 expression, a marker of tumor cell proliferation. A 1.5- to 3-h treatment with PQ1 is sufficient to inhibit the incorporations of [3H]-thymidine into DNA, [3H]-uridine into RNA and [3H]-leucine into protein used to assess the rates of macromolecule syntheses over a 0.5- or 1-h period of pulse-labeling in L1210 tumor cells. A 15-min pretreatment with PQ1 inhibits the cellular transport of both purine and pyrimidine nucleosides over a 30-sec period in vitro, suggesting that PQ1 may prevent the incorporation of [3H]-adenosine and [3H]-thymidine into DNA because it rapidly blocks the uptake of these nucleosides by the tumor cells. Since PQ1 does not reduce the fluorescence of the ethidium bromide-DNA complex, it does not directly bind to or destabilize double-stranded DNA. Over a 6- to -48-h period, PQ1 has very little effect on the mitotic index of L1210 cells but stimulates the formation of many binucleated cells and a few micronuclei, suggesting that this compound might increase mitotic abnormality, induce chromosomal damage or missegregation, and block cytokinesis. The fact that PQ1 induces initiator caspase-2 and effector caspase-3 activities and poly(ADP-ribose) polymerase-1 cleavage within 1-4 h and internucleosomal DNA fragmentation within 24 h in L1210 cells suggests that this antitumor drug can trigger the early and late events required for cells to undergo apotosis. Whole-cell immunodetection and Western blot analysis indicate that, in contrast to 17-(allylamino)-17-demethoxygeldanamycin and radicicol, PQ1 fails to down-regulate the protein level at 24 h and autophosphorylation at 3 h of membrane-anchored HER1 in A-431 cells and HER2 in SK-BR-3 cells, suggesting that this antitumor compound is unlikely to interact with and inhibit Hsp90 and the epidermal growth factor (EGF) receptor signaling pathways. In conclusion, antiproliferative PQ1 is effective against a spectrum of tumor cells and might interact with various membrane and nuclear targets to enhance gap junctions, inhibit nucleoside transport and block cytokinesis but does not appear to disrupt the EGF receptor-mediated signaling pathways to induce growth arrest and apoptosis.

2,2-Disubstituted 2,5-dihydro-4-methyloxazoles (1) were synthesized from 2-aminopropanol in three steps. 3-Oxazolines 1 can be converted into various α-sulfinyl ketimines such as (SS)-{(4-methylphenyl)sulfinylmethyl}-2,2-diethyl-2,5-dihydrooxazole (5) which was stereoselectively reduced with Dibal-H to give 3-hydroxy-2-aminopropyl sulfoxide 7.

New insecticides are urgently needed because resistance to current insecticides allows resurgence of disease-transmitting mosquitoes while concerns for human toxicity from current compounds are growing. We previously reported the finding of a free cysteine (Cys) residue at the entrance of the active site of acetylcholinesterase (AChE) in some insects but not in mammals, birds, and fish. These insects have two AChE genes (AP and AO), and only AP-AChE carries the Cys residue. Most of these insects are disease vectors such as the African malaria mosquito (Anopheles gambiae sensu stricto) or crop pests such as aphids. Recently we reported a Cys-targeting small molecule that irreversibly inhibited all AChE activity extracted from aphids while an identical exposure caused no effect on the human AChE. Full inhibition of AChE in aphids indicates that AP-AChE contributes most of the enzymatic activity and suggests that the Cys residue might serve as a target for developing better aphicides. It is therefore worth investigating whether the Cys-targeting strategy is applicable to mosquitocides. Herein, we report that, under conditions that spare the human AChE, a methanethiosulfonate-containing molecule at 6 microM irreversibly inhibited 95% of the AChE activity extracted from An. gambiae s. str. and >80% of the activity from the yellow fever mosquito (Aedes aegypti L.) or the northern house mosquito (Culex pipiens L.) that is a vector of St. Louis encephalitis. This type of inhibition is fast ( approximately 30 min) and due to conjugation of the inhibitor to the active-site Cys of mosquito AP-AChE, according to our observed reactivation of the methanethiosulfonate-inhibited AChE by 2-mercaptoethanol. We also note that our sulfhydryl agents partially and irreversibly inhibited the human AChE after prolonged exposure (>4 hr). This slow inhibition is due to partial enzyme denaturation by the inhibitor and/or micelles of the inhibitor, according to our studies using atomic force microscopy, circular dichroism spectroscopy, X-ray crystallography, time-resolved fluorescence spectroscopy, and liquid chromatography triple quadrupole mass spectrometry. These results support our view that the mosquito-specific Cys is a viable target for developing new mosquitocides to control disease vectors and to alleviate resistance problems with reduced toxicity toward non-target species.

This report describes the asymmetric induction exhibited in the conjugate addition reaction of the carbanion derived from α-sulfinyl ketimines possessing chiral sulfur with various acyclic and cyclic ene esters,the subsequent cyclisation to lactams,and the stereoselectivity in reductions of the resulting β-sulfinyl enamides.This method is demonstrated in the synthesis of the title compounds

(-)-Lupinine and (+)-epilupinine [(1R,9aR)- and (1S,9aR)-octahydro-1-hydroxymethyl-2H-quinolizine] were synthesized from (+)-2,3,4,5-tetrahydro-6-[(R)-(4-methylphenyl)sulfinylmethyl]pyridine (4) in five steps. The intermediate, 3,4,6,7,8,9-hexahydro-1-[(R)-(4-methylphenyl)sulfinyl]-2H-quinolizine (7), was stereoselectively reduced with cerium(III) chloride heptahydrate and sodium borohydride to give predominantly C-9a-R isomers, (9aR)-octahydro-1-[(R)-(4-methylphenyl)sulfinyl]-2H-quinolizines

The title racemic compound, C 20 H 20 O 5 , an antitumor agent, was obtained from the condensation reaction of 2-cyclohexenecarboxaldehyde and 4-hydroxy-6-(3,4-dimethoxyphenyl)-2-pyrone in the presence of L-proline. The X-ray structure (173K) shows a linear tricyclic skeleton in which the cyclohexane ring has a chair conformation, with the junction H atom axially oriented on the lone asymmetric C atom. The structure is disordered, such that the two enantiomers lie on the same site. The dimethoxyphenyl ring is virtually coplanar with the 2-pyrone ring, the angle between these two planes being 4.56 (11)°.

Alzheimer's disease (AD) is characterized by depositions of beta-amyloid (A beta) aggregates as amyloid in the brain. To facilitate diagnosis of AD by radioligand imaging, several highly specific small-molecule amyloid ligands have been developed. Because amyloid ligands display excellent pharmacokinetics properties and brain bioavailability, and because we have previously shown that some amyloid ligands bind the highly neurotoxic A beta oligomers (A beta O) with high affinities, they may also be valuable candidates for anti-A beta therapies. Here we identified two fluorene compounds from libraries of amyloid ligands, initially based on their ability to block cell death secondary to intracellular A beta O. We found that the lead fluorenes were able to reduce the amyloid burden including the levels of A beta O in cultured neurons and in 5xFAD mice. To explain these in vitro and in vivo effects, we found that the lead fluorenes bind and destabilize A beta O as shown by electron paramagnetic resonance spectroscopy studies, and block the harmful A beta O-synapse interaction. These fluorenes and future derivatives, therefore, have a potential use in AD therapy and research.

Retinal cells which become ischemic will pass apoptotic signal to adjacent cells, resulting in the spread of damage. This occurs through open gap junctions. A class of novel drugs, based on primaquine (PQ), was tested for binding to connexin 43 using simulated docking studies. A novel drug has been synthesized and tested for inhibition of gap junction activity using R28 neuro-retinal cells in culture. Four drugs were initially compared to mefloquine, a known gap junction inhibitor. The drug with optimal inhibitory activity, PQ1, was tested for inhibition and was found to inhibit dye transfer by 70% at 10 microM. Retinal ischemia was produced in R28 cells using cobalt chloride as a chemical agent. This resulted in activation of caspase-3 which was prevented by PQ1, the gap junction inhibitor. Results demonstrate that novel gap junction inhibitors may provide a means to prevent retinal damage during ischemia.

Promising anti-breast cancer agents derived from substituted quinolines were discovered. The quinolines were readily synthesized in a large scale from a sequence of reactions starting from 4-acetamidoanisole. The Michael addition product was isolated as the reaction intermediate in the ring closing reaction of 4-amino-5-nitro-2-(3-trifluoromethylphenyloxy)anisole with methyl vinyl ketone leading to 6-methoxy-4-methyl-8-nitro-5-(3-trifluoromethylphenyloxy)quinoline (14). The amino function of 8-amino-6-methoxy-4-methyl-5-(3-trifluoromethylphenyloxy)quinoline, prepared from 14, was connected to various side chains via alkylation with N-(3-iodopropyl)phthalimide, Michael addition with acrylonitrile, and reductive amination with various heterocycle carboxaldehydes, such as imidazole-4-carboxaldehyde, thiophene-2-carboxaldehyde, and 2-furaldehyde. Effects of the substituted quinolines on cell viability of T47D breast cancer cells using trypan blue exclusion assay were examined. The results showed that the IC(50) value of 6-methoxy-8-[(2-furanylmethyl)amino]-4-methyl-5-(3-trifluoromethylphenyloxy)quinoline is 16+/-3nM, the lowest IC(50) out of all the quinolines tested. IC(50) values of three other quinolines are in the nanomolar range, a desirable range for pharmacological testing.

Total syntheses of (+/-)-ovalicin, its C4(S( *))-isomer 44, and C5-side chain intermediate 46 were accomplished via an intramolecular Heck reaction of (Z)-3-(tert-butyldimethylsilyloxy)-1-iodo-1,6-heptadiene and a catalytic amount of palladium acetate. Subsequent epoxidation, dihydroxylation, methylation, and oxidation led to (3S( *),5R( *),6R( *))-5-methoxy-6-(tert-butyldimethylsilyloxy)-1-oxaspiro[2.5]octan-4-one (2), a reported intermediate. The addition of a side chain with cis-1-lithio-1,5-dimethyl-1,4-hexadiene (27) followed by oxidation afforded (+/-)-ovalicin. The functional group manipulation afforded a number of regio- and stereoisomers, which allow the synthesis of analogs for bioevaluation. The structure of 44 was firmly established via a single-crystal X-ray analysis. The stereochemistry at C4 generated from the addition reactions of alkenyllithium with ketones 2, 40, and 45 is dictated by C6-alkoxy functionality. Anti-trypanosomal activities of various ovalicin analogs and synthetic intermediates were evaluated, and C5-side chain analog, 46, shows the strongest activity. Compound 44 shows antiproliferative effect against HL-60 tumor cells in vitro. Compounds 46 and a precursor, (3S( *),4R( *),5R( *),6R( *))-5-methoxy-4-[(E)-(1',5'-dimethylhexa-1',4'-dienyl)]-6-(tert-butyldimethylsilyloxy)-1-oxaspiro[2.5]octan-4-ol (28), may be explored for the development of anti-parasitic drugs.

α-Lithiated (+)-(R)-4,5-dihydro-2-[[(4-methylphenyl)sulfinyl]methyl]-3H-pyrrole (4) underwent annulation with 1,3-diiodopropane to give (-)-(SS)-1,2,3,5,6,7-hexahydro-8-[(4-methylphenyl)sulfinyl]indolizine (6), which was converted into (-)-elaeokanine B (three steps) and (+)-elaeokanine A (four steps)

Synthetic analogs of 1,4-anthraquinone (AQ code number), which block nucleoside transport, decrease DNA, RNA and protein syntheses, trigger cytochrome c release without caspase activation, induce apoptotic DNA fragmentation and inhibit the proliferation of wild-type and multidrug resistant tumor cells in the nM range in vitro, rapidly cause the collapse of mitochondrial transmembrane potential in cell and cell-free systems. Because mitochondrial permeability transition (MPT) requires more than depolarization to occur, antitumor AQs were tested for their ability to directly trigger specific markers of MPT in isolated mitochondria. In contrast to a spectrum of conventional anticancer drugs that are inactive, various AQs interact with isolated mitochondria in a concentration- and time-dependent manner to rapidly cause large amplitude swelling and Ca2+ release in relation with their effectiveness against L1210, HL-60 and LL/2 tumor cells in vitro. Indeed, the lead antitumor AQ8, AQ9 and AQ17 are also the most effective inducers of MPT in isolated mitochondria, whereas all AQ derivatives devoid of anti-proliferative activity also fail to trigger mitochondrial swelling and Ca2+ release. Moreover, the ability of 4 microM AQ17 to maximally induce mitochondrial swelling and Ca2+ release within 15 min is similar to that of classic MPT-inducing agents, such as 5 microg/ml alamethicin, 200 microM atractyloside, 5 microM phenylarsine oxide, 100 microM arsenic trioxide and a 100 microM Ca2+ overload. Interestingly, AQ17 requires a priming concentration of 20 microM Ca2+ to trigger mitochondrial swelling and Ca2+ release and these 0.1 microM ruthenium red-sensitive MPT events are abolished by 1 microM cyclosporin A, 2 mM ADP and 20 microM bongkrekic acid, which block components of the permeability transition pore (PTP), and also inhibited by 50-100 microM of various ubiquinones, which interact with the quinone binding site of the PTP and raise the Ca2+ load required for PTP opening. Hence, antitumor AQs that target isolated mitochondria and trigger MPT might directly interact with components of the PTP to induce conformational changes that increase its Ca2+ sensitivity and transition from the closed to the open state.

Substituted triptycenes (TT code number), which block nucleoside transport, macromolecule syntheses and DNA topoisomerase activities, induce cytochrome c release and apoptotic DNA fragmentation, inhibit the proliferation of drug-sensitive and -resistant tumor cells in the nM range in vitro and rapidly trigger the collapse of mitochondrial transmembrane potential in cell and cell-free systems. Because mitochondrial permeability transition (MPT) requires more than depolarization, antitumor TTs were tested for their ability to directly trigger specific markers of MPT in isolated mitochondria.Large amplitude swelling and Ca2+ release were assayed in isolated mitochondria to demonstrate TT-induced MPT.Antitumor TTs interact with isolated mitochondria in a concentration- and time-dependent manner to rapidly cause large amplitude swelling and Ca2+ release in relation with their antiproliferative activities in L1210, HL-60 and LL/2 tumor cells in vitro. The ability of 4-10 uM TT15, TT16 and TT24 to maximally induce mitochondrial swelling and Ca2+ release within 20 min is similar to that of classic MPT inducers, such as 5 microg/ml alamethicin, 200 microM atractyloside, 5 microM phenylarsine oxide, 100 microM arsenic trioxide and a 100 microM Ca2+ overload. TT15 requires a priming concentration of 20 microM Ca2+ to trigger mitochondrial swelling and Ca2+ release and these 0.1 microM ruthenium red-sensitive MPT events are abolished by 1 microM cyclosporin A, 2 mM ADP and 20 microM bongkrekic acid, which block components of the permeability transition pore (PTP), and by 50-100 microM of various ubiquinones, which interact with the quinone binding site of the PTP and raise the Ca2+ load required for PTP opening.Antitumor TTs that trigger MPT in isolated mitochondria might interact with components of the PTP to boost its Ca2+-sensitive transition from the closed to the open state and might be valuable to develop mitochondriotoxic drugs that directly activate early components of apoptosis.

Synthetic analogs of 1,4-anthraquinone (AQ code number), which block nucleoside transport, decrease DNA, RNA and protein syntheses, trigger cytochrome c release without caspase activation, induce apoptotic DNA fragmentation and inhibit the proliferation of wild-type and multidrug resistant tumor cells in the nM range in vitro, rapidly cause the collapse of mitochondrial transmembrane potential in cell and cell-free systems. Because mitochondrial permeability transition (MPT) requires more than depolarization to occur, antitumor AQs were tested for their ability to directly trigger specific markers of MPT in isolated mitochondria. In contrast to a spectrum of conventional anticancer drugs that are inactive, various AQs interact with isolated mitochondria in a concentration- and time-dependent manner to rapidly cause large amplitude swelling and Ca2+ release in relation with their effectiveness against L1210, HL-60 and LL/2 tumor cells in vitro. Indeed, the lead antitumor AQ8, AQ9 and AQ17 are also the most effective inducers of MPT in isolated mitochondria, whereas all AQ derivatives devoid of anti-proliferative activity also fail to trigger mitochondrial swelling and Ca2+ release. Moreover, the ability of 4 microM AQ17 to maximally induce mitochondrial swelling and Ca2+ release within 15 min is similar to that of classic MPT-inducing agents, such as 5 microg/ml alamethicin, 200 microM atractyloside, 5 microM phenylarsine oxide, 100 microM arsenic trioxide and a 100 microM Ca2+ overload. Interestingly, AQ17 requires a priming concentration of 20 microM Ca2+ to trigger mitochondrial swelling and Ca2+ release and these 0.1 microM ruthenium red-sensitive MPT events are abolished by 1 microM cyclosporin A, 2 mM ADP and 20 microM bongkrekic acid, which block components of the permeability transition pore (PTP), and also inhibited by 50-100 microM of various ubiquinones, which interact with the quinone binding site of the PTP and raise the Ca2+ load required for PTP opening. Hence, antitumor AQs that target isolated mitochondria and trigger MPT might directly interact with components of the PTP to induce conformational changes that increase its Ca2+ sensitivity and transition from the closed to the open state.

The discovery of small molecule inhibitors of cytotoxicity induced by amyloid-beta (Abeta) oligomers, either applied extracellularly or accumulated intraneuronally, is an important goal of drug development for Alzheimer's disease (AD), but has been limited by the lack of efficient screening methods. Here we describe our approach using two cell-based methods. The first method takes advantage of the unique ability of extracellularly applied Abeta oligomers to rapidly induce the exocytosis of formazan formed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). We employed a short protocol to quantify this toxicity, and quickly identified two novel inhibitors, code-named CP2 and A5, from two compound libraries. A second independent screen of the same libraries using our previously published MC65 protection assay, which identifies inhibitors of toxicity related to intracellular Abeta oligomers, also selected the same two leads, suggesting that both assays select for the same anti-Abeta oligomer properties displayed by these compounds. We further demonstrated that A5 attenuated the progressive aggregation of existing Abeta oligomers, reduced the level of intracellular Abeta oligomers, and prevented the Abeta oligomer-induced death of primary cortical neurons, effects similar to those demonstrated by CP2. Our results suggest that, when combined, the two methods would generate fewer false results and give a high likelihood of identifying leads that show promises in ameliorating Abeta oligomer-induced toxicities within both intraneuronal and extracellular sites. Both assays are simple, suitable for rapid screening of a large number of medicinal libraries, and amenable for automation.

Since synthetic analogs of triptycene (TT code number), such as bisquinones TT2 and TT13, can trigger cytochrome c release without caspase activation and retain their ability to induce apoptosis in multidrug-resistant (MDR) tumor cells, fluorescent probes of transmembrane potential have been used to determine whether these antitumor compounds might directly target mitochondria in cell and cell-free systems to cause the collapse of mitochondrial membrane potential ( downward arrow Deltapsim) that is linked to permeability transition pore (PTP) opening. Using JC-1 dye, the abilities of various TT analogs to induce the downward arrow Deltapsim in wild-type and MDR HL-60 cells are rapid (within 5-20 min), irreversible after drug removal, concentration dependent in the 0.64-25 microM range, and generally related to their antitumor activities in vitro. The downward arrow Deltapsim caused by TT2 and TT13, which are more potent than mitoxantrone, staurosporine and the reference depolarizing agent, carbonyl cyanide m-chlorophenylhydrazone (CCCP), in HL-60 cells, are not prevented by caspase-2 or -8 inhibitors, suggesting that activation of these apical caspases upstream of mitochondria is not involved in this process. Antitumor TT analogs (0.64-25 microM) also mimic the abilities of the known depolarizing agents, CCCP, alamethicin, gramicidin A and 100 microM CaCl(2), to directly induce within 20 min the downward arrow Deltapsim in isolated mitochondria prepared from mouse liver and loaded with rhodamine 123 dye. The fact that 20 microM Ca(2+), which is insufficient to trigger depolarization on its own, is required to reveal the depolarizing effect of TT2 in isolated mitochondria suggests that antitumor TT analogs might interact with the PTP to alter its conformation and increase its Ca(2+) sensitivity. Indeed, such Ca(2+)-dependent downward arrowDeltapsim of isolated mitochondria treated with 25 microM TT2 or 100 microM Ca(2+) are blocked by ruthenium red. Daunorubicin (DAU) is unable to mimic the rapid downward arrowDeltapsim caused by antitumor TT bisquinones within 5-40 min of treatment in HL-60 cells or isolated mitochondria. Moreover, the downward arrowDeltapsim caused by 25 microM TT2 or 100 microM Ca(2+) in isolated mitochondria are similarly blocked by cyclosporin A (CsA), bongkrekic acid and decylubiquinone, which prevent PTP opening, suggesting that, in contrast to DAU, antitumor TT analogs that directly target mitochondria to trigger the Ca(2+)-dependent and CsA-sensitive downward arrowDeltapsim, might induce PTP opening and the mitochondrial pathway of apoptosis even in the absence of nuclear signals.

A remarkable asymmetric induction was observed in the one-pot condensation reaction of (S)-(-)-perillaldehyde with 4-hydroxy-6-methyl-2-pyrone in the presence of L-proline which provided the title compound, C 16 H 18 O 3 , a tricyclic pyrone, as a single diastereomer in 78% yield. As the configuration of the cyclohexane C atom holding the isopropenyl group is the same as that in the (S)-aldehyde substrate, the total absolute stereochemistry could be elucidated from its X-ray structure. The cyclohexane ring has a chair conformation in which the juncture H atom (H5a) is axially oriented and the isopropenyl substituent is equatorial.

Characterization of the title compound, C 15 H 16 O 5 , by X-ray diffraction affirms its linearly fused tricyclic structure and the chair conformation of the cyclohexane ring on which the methyl and adjacent formyloxy groups are cis, the former being axial and the latter equatorial. The C=C bond γ,δ to the carbonyl is longer, while the C=C bond α,β to the carbonyl is shorter than their counterparts in a 3-substituted 4-hydroxy-6-methyl-2-pyrone.

From the reaction of (SR)-(–)-tert-butylsulfinylferrocene with (2,4,6-triisopropylphenyl)lithium followed by paraformaldehyde, the title compound, [Fe(C5H5)(C10H15O2S)], was obtained as an unexpected by-product along with the major product, (SR,1S,2R)-2-(tert-butylsulfinyl)ferrocenylmethanol. The absolute structure of this by-product could not be ascertained via NMR, but it was characterized by X-ray diffraction as (SR,1R,2S)-2-(tertbutylsulfinyl)ferrocenylmethanol, a diastereoisomer of the major product. The two cyclopentadienyl rings are rotated away from one another by 25.5 (5)° (from an eclipsed form towards a gauche form), in contrast to the mutually eclipsed rings generally found in monosubstituted ferrocenes. Hydrogen bonding between sulfoxide O atoms and hydroxyl H atoms produces infinite one-dimensional chains.

Since synthetic analogs of triptycene (TT code number), such as bisquinones TT2 and TT13, can trigger cytochrome c release without caspase activation and retain their ability to induce apoptosis in multidrug-resistant (MDR) tumor cells, fluorescent probes of transmembrane potential have been used to determine whether these antitumor compounds might directly target mitochondria in cell and cell-free systems to cause the collapse of mitochondrial membrane potential ( downward arrow Deltapsim) that is linked to permeability transition pore (PTP) opening. Using JC-1 dye, the abilities of various TT analogs to induce the downward arrow Deltapsim in wild-type and MDR HL-60 cells are rapid (within 5-20 min), irreversible after drug removal, concentration dependent in the 0.64-25 microM range, and generally related to their antitumor activities in vitro. The downward arrow Deltapsim caused by TT2 and TT13, which are more potent than mitoxantrone, staurosporine and the reference depolarizing agent, carbonyl cyanide m-chlorophenylhydrazone (CCCP), in HL-60 cells, are not prevented by caspase-2 or -8 inhibitors, suggesting that activation of these apical caspases upstream of mitochondria is not involved in this process. Antitumor TT analogs (0.64-25 microM) also mimic the abilities of the known depolarizing agents, CCCP, alamethicin, gramicidin A and 100 microM CaCl(2), to directly induce within 20 min the downward arrow Deltapsim in isolated mitochondria prepared from mouse liver and loaded with rhodamine 123 dye. The fact that 20 microM Ca(2+), which is insufficient to trigger depolarization on its own, is required to reveal the depolarizing effect of TT2 in isolated mitochondria suggests that antitumor TT analogs might interact with the PTP to alter its conformation and increase its Ca(2+) sensitivity. Indeed, such Ca(2+)-dependent downward arrowDeltapsim of isolated mitochondria treated with 25 microM TT2 or 100 microM Ca(2+) are blocked by ruthenium red. Daunorubicin (DAU) is unable to mimic the rapid downward arrowDeltapsim caused by antitumor TT bisquinones within 5-40 min of treatment in HL-60 cells or isolated mitochondria. Moreover, the downward arrowDeltapsim caused by 25 microM TT2 or 100 microM Ca(2+) in isolated mitochondria are similarly blocked by cyclosporin A (CsA), bongkrekic acid and decylubiquinone, which prevent PTP opening, suggesting that, in contrast to DAU, antitumor TT analogs that directly target mitochondria to trigger the Ca(2+)-dependent and CsA-sensitive downward arrowDeltapsim, might induce PTP opening and the mitochondrial pathway of apoptosis even in the absence of nuclear signals.

Since synthetic analogs of 1,4-anthraquinone (AQ code number), such as AQ8, AQ9 and AQ10, can trigger cytochrome c release without caspase activation and retain their ability to induce apoptosis in multidrug-resistant (MDR) tumor cells, fluorescent probes of transmembrane potential have been used to determine whether these anti-tumor compounds might directly target mitochondria in cell and cell-free systems to cause the collapse of mitochondrial membrane potential (/Deltapsim) that is linked to permeability transition pore (PTP) opening. Using JC-1 dye, the abilities of various AQ analogs to induce the /Deltapsim in wild-type and MDR HL-60 cells are rapid (within 2.5-10 min), irreversible after drug removal, concentration dependent in the 0.256-10 micromol/l range and generally related to their anti-tumor activities in vitro. The /Deltapsim caused by AQ9 and AQ10, which are more potent than mitoxantrone, staurosporine and the reference depolarizing agent carbonyl cyanide m-chlorophenylhydrazone (CCCP) in HL-60 cells, are not prevented by caspase-2 or -8 inhibitors, suggesting that activations of these apical caspases upstream of mitochondria are not involved in this process. Antitumor AQ analogs (0.256-10 micromol/l) also mimic the abilities of the known depolarizing agents CCCP, alamethicin, gramicidin A and 100 micromol/l CaCl2 to directly induce within 15 min the /Deltapsim in isolated mitochondria prepared from mouse liver and loaded with rhodamine 123 dye. The fact that 20 micromol/l Ca2+, which is insufficient to trigger depolarization on its own, is required to reveal the depolarizing effect of AQ9 in isolated mitochondria suggests that anti-tumor AQ analogs might interact with the PTP to alter its conformation and increase its Ca2+ sensitivity. Indeed, such Ca2+-dependent /Deltapsim of isolated mitochondria treated with 1.6 micromol/l AQ9 or 100 micromol/l Ca2+ are blocked by ruthenium red. Daunorubicin (DAU) is unable to mimic the rapid /Deltapsim caused by anti-tumor AQ analogs within 2.5-40 min of treatment in HL-60 cells or isolated mitochondria. Moreover, the /Deltapsim caused by 1.6 micromol/l AQ9 or 100 micromol/l Ca2+ in isolated mitochondria are similarly blocked by cyclosporin A (CsA), bongkrekic acid and decylubiquinone, which prevent PTP opening, suggesting that, in contrast to DAU, anti-tumor AQ analogs that directly target mitochondria to trigger the Ca2+-dependent and CsA-sensitive /Deltapsim, might induce PTP opening and the mitochondrial pathway of apoptosis even in the absence of nuclear signals.

Tetracyclic pyrans (+)-chloropuupehenone (1) and (+)-chloropuupehenol (5) and its C8-R-isomer (+)-3 were synthesized via a one-pot condensation of 1-chloro-2-lithio-3,5,6-tris(tert-butyldimethylsilyloxy)benzene (8) with (4aS,8aS)-3,4,4a,5,6,7,8,8a-octahydro-2,5,5,8a-tetramethylnaphthalene-1-carboxaldehyde (7). The major condensation product, (4aS,6aR,12bS)-2H-9,10-bis(tert-butyldimethylsilyloxy)-11-chloro-1,3,4,4a,5,6,6a,12b-octahydro-4,4,6a,12b-tetramethyl-benzo[a]xanthene (4), after desilylation provided tetracyclic pyran (+)-(4aS,6aR,12bS)-2H-11-chloro-1,3,4,4a,5,6,6a,12b-octahydro-4,4,6a,12b-tetramethyl-benzo[a]xanthene-9,10-diol (3). At a dosage of 42 mg/rat over 8 h, pyran diol 3 inhibited the intestinal absorption of cholesterol by 71% in rats. Tetracyclic pyran 4 was also converted to o-quinone 28, which inhibited cholesteryl ester transfer protein (CETP) activity and L1210 leukemic cell viability with IC(50) values of 31 and 2.4 microM, respectively. Diol (+)-5 inhibited CETP activity with an IC(50) value of 16 microM. The minor condensation product, (4aS,6aS,12bS)-2H-9,10-bis(tert-butyldimethylsilyloxy)-11-chloro-1,3,4,4a,5,6,6a,12b-octahydro-4,4,6a,12b-tetramethyl-benzo[a]xanthene (6), was transformed into (+)-5 and (+)-1. A stepwise stereoselective synthesis of (+)-1 was also developed utilizing an oxyselenylation ring-closure reaction. The synthetic sequence also produced four biologically active naturally occurring drimanic sesquiterpenes, (+)-drimane-8alpha,11-diol (34), (-)-drimenol (38), (+)-albicanol (39), and (-)-albicanal (31) as intermediates.

The purpose of this study was to determine the effects of a novel aldose reductase inhibitor on lens protein kinase Cgamma (PKCgamma) levels in galactosemic dogs. Six-month old Beagles (12 total; 6 male and 6 female) were made galactosemic by feeding a diet of 40% galactose for 6 weeks. Three dogs per group were fed either control, normal diet, 40% galactose diet, 40% galactose diet with aldose reductase inhibitor at 100 mg/kg body weight per day given orally, or a control diet with aldose reductase inhibitor alone (1-H,7-H-5alpha,6,8,9-tetrahydro-1-oxopyran[4,3-beta](1) benzopyran, referred to herein as HAR-1). Lenses were removed and analyzed for toxicity by pathological examination. Lens polyol concentrations were determined by GC/MS. PKCgamma levels were determined by Western blot and by reverse transcriptase-polymerase chain reaction (RT-PCR). No toxicity was observed from the aldose reductase inhibitor when given at 100 mg/kg body weight per day for 6 weeks. Galactosemic dogs showed deterioration of lens cells. Deterioration included vacuole formation in the lens, cell lysis, and loss of cell nuclei. Galactosemic dogs given the HAR-1 appeared identical to control dogs. Polyol concentrations in the lenses were reduced by 50% in dogs fed the 40% galactose diet with the aldose reductase inhibitor, HAR-1. PKCgamma protein levels were reduced in the galactosemic dog lenses, but synthesis of PKCgamma was not affected, as measured by RT-PCR. The PKCgamma protein levels were similar to controls in dogs given the aldose reductase inhibitor, HAR-1, even when polyol concentrations remained 50% elevated above control levels. HAR-1, when given to control dogs, caused a reduction in the synthesis of PKCgamma mRNA but not in total PKCgamma protein levels. This study demonstrates the use of a novel aldose reductase inhibitor to control changes in PKCgamma in dog lens, a PKC that is known to control gap junction activity.

Synthetic triptycene analogs (TT code number) mimic the antitumor effects of daunorubicin in the nanomolar range in vitro, but have the advantage of blocking nucleoside transport and retaining their efficacy in multidrug-resistant (MDR) tumor cells. Since TT bisquinones induce poly(ADP-ribose) polymerase-1 cleavage at 6 h and internucleosomal DNA fragmentation at 24 h, which are, respectively, early and late markers of apoptosis, these lead antitumor drugs were tested for their ability to trigger the DNA topoisomerase (Topo) inhibitions responsible for the initial and massive high-molecular-weight cleavage of DNA required for tumor cells to commit apoptosis. Interestingly, antitumor TTs have the unusual ability to inhibit, in a concentration-dependent manner, the relaxation of supercoiled plasmid DNA catalyzed by both purified human Topo I and II enzymes. However, if there is a relationship between the ability of TT analogs to inhibit Topo activities and their quinone functionality and cytotoxicity, it is far from perfect, suggesting that other molecular targets may be involved in the mechanism of action of these antitumor drugs. Moreover, one of the most cytotoxic TT bisquinone, 6-bromo-7-methoxy- or 7-bromo-6-methoxy-2-N-methylamino-1 H,4 H,5 H,8H-9,10-dihydro-9,10-[1',2']benzenoanthracene-1,4,5,8-tetraone (TT24), inhibits Topo II activity more effectively than amsacrine (m-AMSA) and matches the Topo I inhibitory effect of camptothecin (CPT). The dual inhibitory activity of TT24 is substantiated by the findings that TT24 mimics the action of m-AMSA in the Topo II assay, where the Topo I inhibitor CPT is ineffective, and also mimics the action of CPT in the Topo I assay, where the Topo II inhibitor etoposide is ineffective. Because of their ability to target nucleoside transport and topoisomerase activities, synthetic TT bisquinones might represent a novel class of bifunctional drugs valuable to develop new means of polychemotherapy and circumvent MDR.

Most alkyl phenyl sulfones are readily α-chlorinated with CCl4 and α-brominated with CBrCl3 in KOH−t-BuOH via radical−anion radical pair (RARP) reactions. While isopropyl mesityl sulfone (4) is easily α-chlorinated with CCl4, it was completely recovered when treated with the more reactive CBrCl3. Subsequent investigations showed the latter result to be due to the poor acidity of 4 together with the rapid depletion of CBrCl3 and KOH by their reaction with each other, and led to a variety of other important results. 4-Hydroxyphenyl isopropyl sulfone (6) is unreactive with either CCl4 or CBrCl3 in KOH−t-BuOH, its phenoxide anion strongly reducing the electronegativity of the sulfonyl group, thereby inhibiting α-anion formation. This effect is reversed by the electron-withdrawing influence of two α-phenyls, so that benzhydryl 4-hydroxyphenyl sulfone (8) is readily α-halogenated in KOH−t-BuOH with CCl4 or CBrCl3. On further contact with KOH−t-BuOH the α-halogenated sulfones from 8 are decomposed into benzophen...

Synthetic analogs of 1,4-anthraquinone (AQ code number), a compound that mimics the antiproliferative effects of daunorubicin (daunomycin) in the nanomolar range in vitro but has the advantage of blocking nucleoside transport and retaining its efficacy in multidrug-resistant tumor cells, were tested for their ability to induce apoptosis in the HL-60 cell system. AQ10 and, especially, the new lead antiproliferative compounds AQ8 and AQ9 reduce the growth and integrity of wild-type, drug-sensitive, HL-60-S cells more effectively than AQ1, suggesting that various methyl group substituents at C6 may enhance the bioactivity of the parent compound. Internucleosomal DNA fragmentation, a late marker of apoptosis, is similarly induced in a biphasic manner by increasing concentrations of AQ8 and AQ9 at 24 hr. Poly(ADP-ribose) polymerase-1 (PARP-1) cleavage, an early event required for cells committed to apoptosis, is detected within 3–6 hr in HL-60-S cells treated with AQ9. In accord with the fact that the caspases 9 and 3 cascade is responsible for PARP-1 cleavage, the activities of initiator caspase-9 and effector caspase-3 are induced by AQ9 in the same time- and concentration-dependent manners and to the same maximal degrees in both the HL-60-S and multidrug-resistant HL-60-RV cell lines. Interestingly, a 1-hr pulse treatment is sufficient for AQ8 and AQ9 to maximally induce caspase-9 and -3 activities at 6 hr. The release of mitochondrial cytochrome c (Cyt c ) is also detected within 3–6 hr in HL-60-S cells treated with AQ9, a finding consistent with the fact that Cyt c is the apoptotic trigger that activates caspase-9. Moreover, AQ analogs induce Cyt c release, caspase-9 and -3 activities and PARP-1 cleavage in relation with their abilities to decrease tumor cell growth and integrity, AQ8 and AQ9 being consistently the most effective. Since apical caspases 2 and 8 may both act upstream of mitochondria to promote Cyt c release, it is significant to show that AQ9 maximally induces caspase-2 and -8 activities at 6 and 9 hr, respectively. During AQ8 treatment, the caspase-2 inhibitor benzyloxycarbonyl (z)-Val-Asp-Val-Ala-Asp (VDVAD)-fluoromethyl ketone (fmk) totally blocks caspase-9, -3, and -8 activations, whereas the caspase-8 inhibitor z-Ile-Glu-Thr-Asp-(IETD)-fmk does not prevent caspase-2, -9, and -3 activations, suggesting that AQ-induced caspase-2 activity is an upstream event critical for the activation of the downstream caspases 9 and 3 cascade, including the mitochondrial amplification loop through caspase-8. However, these caspase-2 and -8 inhibitors fail to alter AQ8-induced Cyt c release, suggesting that AQs might also target mitochondria independently from caspase activation. Furthermore, the antagonistic anti-Fas DX2 and ZB4 monoclonal antibodies (mAbs), which block the induction of Cyt c release and caspase-2, -8, and -9 activities by the agonistic anti-Fas CH11 mAb, and the neutralizing anti-Fas ligand (FasL) NOK-1 mAb all fail to inhibit AQ9-induced Cyt c release and caspase-2, -8, and -9 activities, suggesting that the FasL/Fas signaling pathway is not involved in the mechanism by which antiproliferative AQ analogs trigger apoptosis in HL-60 cells.

In contrast to their inactive parent compound triptycene (code name TT0), new synthetic analogs (TT code number) mimic the antitumor effects of the anthracycline quinone antibiotic daunorubicin (DAU) in the nM range in vitro but have the additional advantage of also blocking nucleoside transport and retaining their efficacy in multidrug-resistant (MDR) tumor cells. Since TT bisquinones may induce DNA fragmentation at 24 h by an active mechanism that requires RNA and protein syntheses and protease activities, the most cytotoxic of them, TT24, was tested for its ability to induce poly(ADP-ribose) polymerase-1 (PARP-1) cleavage, an early marker of apoptosis. PARP-1 cleavage starts at 2-3 h and is maximally induced at 6 h by 1.6 microM concentrations of TT24 and DAU in wild-type drug-sensitive HL-60-S cells. However, in MDR HL-60-RV cells, PARP-1 cleavage is still induced by 4 microM TT24 but not by 4-10 microM DAU. The magnitude of PARP-1 cleavage may increase with the number of quinoid rings in the triptych structure and, in contrast to TT0, all lead antitumor TT bisquinones share the ability to fully induce PARP-1 cleavage in HL-60-S cells. A 1 h pulse treatment is sufficient for TT24 and DAU to induce PARP-1 cleavage at 6 h. Since the abilities of TT24 and DAU to induce PARP-1 cleavage are inhibited by benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone but not by N-tosyl-L-phenylalanine chloromethyl ketone, caspase-mediated apoptosis may be involved in the mechanism by which these quinone antitumor drugs induce the proteolytic cleavage of PARP-1 at 6 h and the internucleosomal fragmentation of DNA at 24 h in the HL-60 tumor cell system.

In contrast to their inactive parent compound triptycene (code name TT0), several new synthetic analogs (TT code number) have antileukemic activities and remain effective in daunorubicin (DAU)-resistant tumor sublines in vitro. Among variously substituted 9,10-dihydro-9,10-[1,2]benzenoanthracene-1,4,5,8-tetraones, a total of six lead antitumor compounds have been identified, and their code names are TT2, TT13, TT16, TT19, TT21 and TT24. These active antitumor triptych structures have bisquinone functionality, and various bromo, methoxy, methylamino and/or dimethylamino substitutions with or without longer alkyl chains on the amino function. Like the anthracycline quinone antibiotic DAU, these triptycene (TT) bisquinones also inhibit DNA synthesis and induce DNA cleavage in relation with their cytotoxic activities, but have the additional advantage of blocking the cellular transport of purine and pyrimidine nucleosides, an effect which DAU cannot do. As demonstrated by intact chromatin precipitation and agarose gel electrophoresis, the ability of TT bisquinones and DAU to induce DNA fragmentation is biphasic with a peak that shifts to lower concentrations with increasing times of drug exposure. The most effective lead antitumor compound, TT24, induces DNA cleavage in the same concentration-dependent manner as DAU at 24 h (similar peak in response to 1.6 microM) and is nearly equipotent to DAU against L1210 tumor cell viability at day 4 (IC50 values of TT24 and DAU: 48 and 25 nM, respectively). The mechanism by which TT24 induces DNA fragmentation is inhibited by actinomycin D, cycloheximide, benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone, benzyloxycarbonyl-Ile-Glu-Thr-Asp-fluoromethyl ketone, N-tosyl-L-phenylalanine chloromethyl ketone and ZnSO4, suggesting that TT bisquinones trigger apoptosis by caspase and endonuclease activation. Since TT24 is cytotoxic in the nanomolar range of DAU, but might have a more versatile mechanism of action than DAU in wild-type and multidrug-resistant tumor cells, this new class of DNA-damaging quinone antitumor drugs inhibiting nucleoside transport might be valuable to develop new means of polychemotherapy.

Ring closure of methyl (2S,3R)-N-[(3-hydroxy-3-phenyl)-2-propyl]carbamate by treatment with p-toluene-sulfonyl chloride and pyridine leads to the title compound in which the oxazolidinone ring is puckered with C5 out of the plane by 21.56 o . C 10 H 11 NO 2 crystallizes in P2 1 with a=5.950, b=8.238, c=9.952A, β=102.82°, Z=2, R=0.029

Pancreatic cancer remains the fourth leading cause of cancer related deaths in the United States. Therefore, identification of novel strategies to control and treat pancreatic cancer is of great importance. GS-19 is a novel compound recently found to be a GSK inhibitor. In this study, we determined the anti-cancer effects of GS-19 in pancreatic cancer cells. GS-19 treatment inhibited the growth of Panc-1 and BxPC-3 cells in a concentration-dependent manner. Both the cell lines treated with GS-19 exhibited G-1 cell cycle arrest as well as apoptosis. Western blot analysis of both BxPC-3 and Panc-1 cells treated with GS-19 inhibited the activation (phosphorylation) and expression of key survival signaling proteins such as EGFR, STAT3 and AKT. The apoptosis induced by GS-19 was associated with cleavage of caspase-3 and PARP. Taken together, our results suggest that GS-19 suppress pancreatic cancer cell growth by inhibiting EGFR/AKT/STAT-3 signaling. However, further mechanistic studies are in progress to establish the role of EGFR/AKT/STAT-3 signaling in pancreatic cancer cells. [The studies in part were supported by R01 grant CA129038 awarded by NIH to S.K.S.] Citation Format: Alok Ranjan, Ashlee Birkenfeld, Jianyu Lu, Duy Hua, Sanjay K. Srivastava. GS-19, a novel GSK inhibitor suppresses the growth of pancreatic cancer cells by inhibiting EGFR/AKT/STAT-3 signaling. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4115. doi:10.1158/1538-7445.AM2014-4115

In contrast to the parent triptycene (code name TT0), triptycene bisquinone (code name TT2) is cytostatic (IC50: 300 nM) and cytotoxic (IC50: 230 nM) in wild-type (WT), drug-sensitive HL-60 cells (HL-60-S) at day 4. Therefore, the effects of this new quinone antitumor drug were assessed and compared to those of daunorubicin (DAU, daunomycin) in the multidrug-resistant (MDR) HL-60-RV and HL-60-R8 sublines, which respectively overexpress P-glycoprotein (P-gp) or multidrug resistance-associated protein (MRP). In contrast to DAU, which loses its cytostatic [resistance factors (RFs): 22.9-35.7] and cytotoxic (RFs: 23.8-31.3) activities in MDR sublines, TT2 decreases tumor cell proliferation (RFs: 0.9-1.3) and viability (RFs: 0.9-1.5) as effectively in HL-60-S as in HL-60-RV and HL-60-R8 cells at days 2 and 4. Similarly, DAU inhibits the rate of DNA synthesis less effectively in MDR than in parental HL-60 cells (RFs: 8.1-11.9) but TT2 decreases the incorporation of 3[H]-thymidine into DNA to the same degree in HL-60-S, HL-60-RV and HL-60-R8 cells (RFs: 1.2). In contrast to DAU, which is inactive, the advantage of TT2 is its ability to block the cellular transport of purine and pyrimidine nucleosides in WT tumor cells, an effect which persists in both MDR sublines (RFs: 1.0-1.2). Moreover, the concentrations of DAU which induce maximal DNA cleavage in HL-60-S cells at 24 h lose all or most of their DNA-damaging activity in HL-60-RV and HL-60-R8 cells, whereas treatments with 4 microM TT2 produce similar peaks of DNA fragmentation in all WT and MDR cell lines. Since TT2 not only mimics the antitumor effects of DAU but also blocks nucleoside transport and retains its effectiveness in MDR cells that have already developed different mechanisms of resistance to DAU, this new quinone antitumor drug might be valuable to develop new means of polychemotherapy.

Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by the progressive and global loss of cognitive functions. Pathological features include a loss of neurons in vulnerable brain regions and the extracellular deposition of abnormal protein aggregates known as amyloid plaques. Amyloid-beta protein (A beta is the major component of amyloid plaques and is derived from a larger transmembrane glycoprotein, termed amyloid beta protein precursor (APP), by proteolysis. The AD research has focused on A beta production and metabolism, its extracellular deposition, and its cellular toxicity. Recent evidence, however, suggests that A beta as well as the C-terminal fragments (CTF) of APP can accumulate intraneuronally. The neuronal loss and synaptic transmission deficit in AD may therefore depend on intraneuronal accumulation of A beta/CTF rather than on extracellular plaque formation. Accordingly, we propose that one of the primary targets of therapeutic intervention should be intracellular A beta/CTF and its toxic cellular effect. We have established a cell-culture model in which the neurons degenerate on induction of endogenous expression of A beta/CTF of APP. These cultures have been used to test whether tricyclic pyrone (TP) compounds may prevent A beta/CTF-mediated neuronal death. The results to date have been encouraging. Lead compounds will now be selected for their abilities to ameliorate A beta/CTF-mediated pathology in transgenic mice. Our hope is that these compounds may eventually prove beneficial for the prevention and treatment of AD.

(R)-Carvone was used as a chiral building block. Regio- and stereoselective alkylations at C6 and C2 of (R)-carvone and (R)-5-isopropyl-2-methyl-2-cyclohexenone [derived from the hydrogenation of (R)-carvone] followed by palladium-mediated ring closures afforded various enantiopure bicyclic and tricyclic alkenones. Hence, cyclization of (5S,6S)-2,6-dimethyl-6-(cis-3-iodo-2-propenyl)-5-isopropenyl-2-cyclohexenone (3) gave (4aS,5S,8aS)-1,4,4a,5,8,8a-hexahydro-5-(methoxycarbonylmethyl)-2,5,8a-trimethylnaphthalen-1-one (7) as the major product, cyclization of (5S,6S)-2,6-dimethyl-6-(cis-3-iodo-2-propenyl)-5-isopropyl-2-cyclohexenone (22) produced (1S,5R,6S)-1,5-dimethyl-6-isopropyltricyclo[3.3.1.02,8]-3-nonen-9-one (23), and cyclization of (2R,5S,6S)-2,6-dimethyl-2-(cis-3-iodo-2-propenyl)-5-isopropenyl-3-cyclohexen-1-one (25) afforded (3aR,6S,7aR)-6,7a-dimethyl-5-isopropenyl-3a,6,7,7a-tetrahydro-1H-inden-7-one (26). A 1,2-rearrangement reaction of bromide 16 gave hexahydro-1H-benzocycloheptene 17.