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The reactions of iodoflavone with 3-methyl-3-hydroxybut-1-yne and 3-methylbut-3-en-2-yne are described and the antimicrobial and cytotoxic activities of the obtained compounds have been tested. The molecular structures of 6-(3-hydroxy-3-methylbut-1-ynyl)-flavone (1a) and 6-(3-methylbut-3-en-1-ynyl) flavone (1b) have been determined by X-ray crystallography. The planar configuration of the two compounds has been attributed to intramolecular hydrogen bond interactions. In 1a, the presence of the hydroxyl group determines a dimeric arrangement of the molecules. In both compounds in the crystal state, molecular stacking has been observed.

This paper reports synthesis and characterization, by spectroscopic methods, of three new N-methyl-5-phenyl-7-chloro-1,2,3-triazolo[4,5-d]pyrimidine isomers 3a, 3b and 3c. For comparison purpose the 3-benzyl-5-phenyl-7-chloro-1,2,3-triazolo[4,5-d]pyrimidine (7) was also prepared. Starting from the isomer mixture 3a-c and the chloroderivative 7, by nucleophilic substitution reaction with ethyl carbazate and subsequent intramolecular cyclization, the new tricyclic derivatives 5a-c and 9 were prepared and tested towards the benzodiazepine and adenosine A1 and A2A receptors.

This paper reports the synthesis of a series of new 5-substituted-1-(2-hydroxybenzoyl)-benzotriazoles, which have been tested for their activity as possible activators of potassium channels. In rat aortic rings, the 'opened' derivatives 1a-f, intermediates of synthesis, showed vasorelaxing properties, with appreciable values of potency. However, the most remarkable effects were recorded for the 2-hydroxybenzoylbenzotriazoles 3a-f, which showed full vasorelaxing efficacy and high potency values. The introduction of a 2-hydroxybenzyl substituent in the 1 position of the benzotriazole ring (compound 7) strongly decreased the activity, showing the importance of the electron-acceptor carbonyl function. The best compound, 3b, was further investigated, in order to evaluate the possible mechanism of action involved in the vasodilator activity. In the vascular model, different potassium channel blockers inhibited the effects of the compound, and an increase of the levels of membrane depolarisation induced a significant reduction of the recorded responses. Compound 3b was also tested in a model of isolated rat heart, retroperfused through the aorta and submitted to a global ischemia/reperfusion cycle. In such an experimental condition, 3b showed an interesting cardioprotective activity. All the above observations are in agreement with the hypothesis of a mechanism linked to the activation of potassium channels.

Synthesis and reactions of 6-chloro-7-fluoro-4-oxo-4H-chromene-3-carboxylic acid are described. The molecular structure of its achiral heterotopic 3-diethoxy-methyl precursor has been determined by NMR spectroscopy and X-ray crystallography. C14H14ClFO4 is monoclinic, space group P21/a, with unit cell dimensions a = 14.923(5), b = 6.615(2), c = 14.921(5) Å, β = 101.44(3)°, V = 1443.7(8) Å3, Z = 4, D calc. = 1.383 g/cm3.

The inosose derivative 3 was obtained with high stereoselectivity by intramolecular aldol condensation of the aldohexos-5-ulose derivative 2 , and it was selectively reduced and debenzylated to give epi -inositol in high yield. The stereochemistry and the preferred conformations of compounds 3 – 7 were determined through 1D and 2D NMR experiments.

The unreported title compound and its 2,6-di-O-benzyl derivative have been prepared from methyl β-D-galactopyranoside through a sequence involving the bisglycoside methyl 2,6-di-O-benzyl-5-O-methoxv-β-D-galactopyranoside 8, the precursor of L-orabino-hexos-5-ulose, that was converted to the L-lyxo series by inversion at C-3. The inversion was achieved in acceptable yields by selective triflation, followed by displacement with benzoate, and by an oxidation/reduction sequence. Whereas 2,5-di-O-benzyl-L-lyxo-hexos-5-ulose exists entirely as a mixture of the two anomeric 1,4-furanosic forms, the unprotected hexos-5-ulose involves at equilibrium in CD3CN/D2O at least eight tautomers, one of which is predominant.

The known oxidation-oximation-reduction sequence leading from d -galactopyranosides to 2-amino-2-deoxy- d -talopyranosides through replacement of the 2-hydroxy by a 2-amino group with inversion has been reinvestigated. The easily obtainable methyl 3,4-O- isopropylidene -6-O-(1- methoxy-1-methylethyl)-β- d -galactopyranoside ( 1 ) was chosen as the suitably protected starting material. The single steps in the synthetic sequence were analyzed in some detail from the point of view of different reagents, stereoselectivities, side products, NMR spectra and conformations of intermediates. Owing to side reactions in the oxidative and reductive steps and to the incomplete diastereoselectivity in the latter, the overall yields in the conversion of 1 into methyl 2- acetamido -6-O- acetyl-2-deoxy -3,4-O- isopropylidene-β- d -talopyranoside did not exceed 50%.

Several new 1,2,3-triazolo[4,5-b][1,4]diazepines were prepared starting from 1-benzyl-1 and 1-phenethyl-4,5-diamino-1,2,3-triazole 2 (Scheme 1), by condensation reactions with β-diketones (Scheme 2), β-ketoesters (Scheme 3), and diethyl malonates (Scheme 4). In the first case we obtained compounds 3 and 4 with basic properties, while the ester function condensations gave cyclic amide derivatives 7, 8, 10, 12 and 13 with acid properties. Some N-methyl derivatives 11, 14 and 15 were obtained from the cyclic amide compounds. Most of compounds were tested for their ability to displace [3H]flunitrazepam from bovine brain membranes but no compound showed benzodiazepine receptor binding affinity.

3,4-Epoxytetrahydrofuran is hydrolyzed by rabbit liver microsomal epoxide hydrolase (MEH) with a high preference for the attack by water at the (S) epoxide carbon to give the (R,R)-diol with an e.e. of 96.5±0.3%. In the acid catalyzed hydrolysis of trans-3,3a-epoxyoctahydrobenzofuran the oxirane ring is opened with inversion exclusively on the tertiary carbon atom to give the corresponding trans-diol, whereas hydrolysis of the cis isomer is less regioselective, the ratio of attack at the tertiary and secondary carbons being 81:19. The MEH catalyzed hydrolysis of the same two substrates occurs exclusively at their secondary epoxide carbons and with a very high enantioselectivity: only enantiomers of configuration (3S,3aR) of the cis- and trans-epoxide are substrates for the enzyme and give the corresponding (3R,3aR)-diols with at least 98% e.e., the corresponding (3R,3aS)-epoxides being totally resistant to enzymatic hydrolysis. These results agree well with previously formulated rules on steric requirements of MEH subtrates. Absolute configurations and optical purities of new chiral compounds were obtained by chiroptical, NMR and chiral chromatographic techniques. Conformations of the octahydrobenzofuran derivatives were derived from coupling constants and found to be in fairly good agreement with those deduced from molecular mechanics calculations.

Several 9-(2′,3′-O-isopropylidene)- and 9-(2′,3′-dihydroxypropyl)-8-azahypoxanthines and 8-azaadenines were synthesized by a “one pot” method starting from the acetonide of racemic or (S)-1-azido-2,3-dihydroxypropane, obtained from D-mannitol. 9-(2′,3′-Dihydroxypropyl)-8-azapurines were tested as adenosine deaminase inhibitors.

3,4-Epoxytetrahydrofuran is hydrolyzed by rabbit liver microsomal epoxide hydrolase (MEH) with a high preference for the attack by water at the (S) epoxide carbon to give the (R,R)-diol with an e.e. of 96.5±0.3%. In the acid catalyzed hydrolysis of trans-3,3a-epoxyoctahydrobenzofuran the oxirane ring is opened with inversion exclusively on the tertiary carbon atom to give the corresponding trans-diol, whereas hydrolysis of the cis isomer is less regioselective, the ratio of attack at the tertiary and secondary carbons being 81:19. The MEH catalyzed hydrolysis of the same two substrates occurs exclusively at their secondary epoxide carbons and with a very high enantioselectivity: only enantiomers of configuration (3S,3aR) of the cis- and trans-epoxide are substrates for the enzyme and give the corresponding (3R,3aR)-diols with at least 98% e.e., the corresponding (3R,3aS)-epoxides being totally resistant to enzymatic hydrolysis. These results agree well with previously formulated rules on steric requirements of MEH subtrates. Absolute configurations and optical purities of new chiral compounds were obtained by chiroptical, NMR and chiral chromatographic techniques. Conformations of the octahydrobenzofuran derivatives were derived from coupling constants and found to be in fairly good agreement with those deduced from molecular mechanics calculations.

This paper reports the synthesis of new 1,2,3-triazolo[1,4]benzodiazepine and 1,2,3-triazolo[1,5]benzodiazepine derivatives and their evaluation toward benzodiazepine receptors. Receptor affinity gradually and remarkably increases by moving the nitrogen atom of the central ring from position 3 through 4 to position 5, to give the most effective compound 6a (Ki=150 nM). N-methylation of the diazepine ring (7a) lowers receptorial binding. Introduction of a chlorine atom on the benzene ring doubles the Ki value (6b) which remains unaltered by the N-methylation (7b).

This paper reports the synthesis and evaluation of the biological affinity towards benzodiazepine and A(1) and A(2A) adenosine receptors of some 3-ethoxycarbonyl or 3-phenyl-substituted 1,2, 3-triazolo[1,5-a]quinazolines. Starting from the appropriate chloro-substituted phenylazides, the series of 7 or 8 chloro-substituted triazoloquinazolines were prepared. Nitration reactions of the triazoloquinazoline ring and chlorination reactions of the hydroxyl group in the 5 position of the same ring are also reported. By nucleophilic displacement of halogen, the corresponding 5-amino derivatives and some analogous derivatives bearing cyclohexylamino and p-toluidino substituents were obtained. The binding assays showed a generalized decrease in the affinity towards the benzodiazepine receptors and confirmed a moderate affinity towards the A(1) adenosine receptors in comparison with the previously studied triazoloquinazoline derivatives.

3,4-O-Isopropylidene derivatives of the title compounds have been prepared by new methods and found to exhibit a high preference for tautomeric forms deriving from hemiacetalization between 6-CH2OH, or 6-CH(OH)2, and 2-CO functions.

Meta-chloroperbenzoic acid can be used as a mild and selective reagent for the removal of the O-propenyl group in the deprotection sequence of allyl protected hydroxyl functions. Its use is illustrated in four synthetic pathways, leading, respectively, to methyl 3-0-acetyl-4- deoxy-6-0-( 1-methoxy-1-methylethyl)-α-L-threo-4-hexenopyranoside, to methyl 2-O-acetyl-3,4,6-tri-O-methyl-α- and β-D-galactopyranoside and to benzyl 6-O-allyl-3,4-0-isopropylidene-β-D-galactopyranoside.

This paper reports the synthesis and evaluation of the biological affinity towards benzodiazepine and A(1) and A(2A) adenosine receptors of some 3-ethoxycarbonyl or 3-phenyl-substituted 1,2, 3-triazolo[1,5-a]quinazolines. Starting from the appropriate chloro-substituted phenylazides, the series of 7 or 8 chloro-substituted triazoloquinazolines were prepared. Nitration reactions of the triazoloquinazoline ring and chlorination reactions of the hydroxyl group in the 5 position of the same ring are also reported. By nucleophilic displacement of halogen, the corresponding 5-amino derivatives and some analogous derivatives bearing cyclohexylamino and p-toluidino substituents were obtained. The binding assays showed a generalized decrease in the affinity towards the benzodiazepine receptors and confirmed a moderate affinity towards the A(1) adenosine receptors in comparison with the previously studied triazoloquinazoline derivatives.

A series of 1,8-naphthyridine derivatives (12-36), bearing a phenyl group in position 2 and various substituents in positions 4 and 7, were synthesized in an attempt to obtain potent, selective antagonists for the A1 adenosine receptor subtype. The compounds were tested to evaluate their affinity for A1 compared with A2A and A3 adenosine receptor subtypes. In binding studies in bovine brain cortical membranes, most of the compounds showed an affinity for A1 receptors in the low nanomolar range and two in the subnanomolar range with an interesting degree of A1 versus A2A and A3 selectivity. Comparison of the 4-substituted derivatives indicated that 4-OH substitution, with a 4-quinoid structure, causes an increase in the A1 and A2A affinity and generally also in A1 selectivity. The kind of substitution in position 7 can greatly modulate the affinity: the most interesting substituents in this position seemed to be electron-withdrawing groups; in particular the 7-chloronaphthyridine 25d showed a remarkable selectivity (A2A/A1 ratio of 670, A3/A1 ratio of 14,000) associated with a higher A1 affinity (Ki = 0.15 nM). NMR studies on these compounds 12-36 indicated that the 4-OH-substituted ones prefer the tautomer in which the oxygen in position 4 is in the quinoid form and the nitrogen in position 1 is protonated. Theoretical calculations are in agreement with the NMR data.

The title compound, previously unreported in either enantioform, and its 2,6-di-O-benzyl derivative have been synthesized through a stereocontrolled epimerization at C-2 of 6-O-protected methyl 3,4-O-isopropylidene-5-C-methoxy-β-D-galactopyranosides. The epimerization, performed through a high yielding sequence of oxidation-reduction owing to the cooperative role of the equatorial C-1 aglycon and the steric hindrance of the isopropylidene group, turned out to be completely diastereoselective. Whereas the unprotected L-ribo-hexos-5-ulose exists, as proved by NMR in D2O, in five main tautomeric forms in a ratio of about 4:2:2:1:1, only two anomeric 1,4-furanosic forms are present at equilibrium in its 2,6-di-O-benzyl derivative, in ratios ranging from 10:1 to 7:3, depending on the prevalence of D2O or CD3CN in the solvent mixture.

This paper reports the synthesis of new 1,2,3-triazolo[1,4]benzodiazepine and 1,2,3-triazolo[1,5]benzodiazepine derivatives and their evaluation toward benzodiazepine receptors. Receptor affinity gradually and remarkably increases by moving the nitrogen atom of the central ring from position 3 through 4 to position 5, to give the most effective compound 6a (Ki=150 nM). N-methylation of the diazepine ring (7a) lowers receptorial binding. Introduction of a chlorine atom on the benzene ring doubles the Ki value (6b) which remains unaltered by the N-methylation (7b).

3,4- O -Isopropylidene- d - lyxo -hexopyranosid-2-ulose derivatives, obtained by oxidation of 3,4,6-protected d -galactopyranosides, can be alkylated in their anionic 2,6-pyranose forms to produce bis-glycosides containing the 2,5-dioxabicyclo[2.2.2]octane ring system. The 1-benzyl-2-methyl bis-glycoside 4b , when subjected to catalytic hydrogenolysis, produces the methyl d - lyxo -hexopyranos-2-uloside 10 , existing as an 8:2 mixture of 1,5-pyranose anomers 9 . Computational and NMR evidence is presented in favour of the hypothesis that the major anomer has the α configuration. Reduction of 9/10 with NaBH 4 gives methyl 3,4- O -isopropylidene-β- d -tagatopyranoside, that can be hydrolyzed to d -tagatose. A simple synthesis of 1,5-anhydro- d -tagatose, starting from 1,5-anhydro- d -galactitol, is also presented. All new compounds were fully characterized by elemental analysis and by 1 H and 13 C NMR spectroscopy.

Several 9-(2′,3′-O-isopropylidene)- and 9-(2′,3′-dihydroxypropyl)-8-azahypoxanthines and 8-azaadenines were synthesized by a “one pot” method starting from the acetonide of racemic or (S)-1-azido-2,3-dihydroxypropane, obtained from D-mannitol. 9-(2′,3′-Dihydroxypropyl)-8-azapurines were tested as adenosine deaminase inhibitors.

5-C-alkoxy-β-D-galactopyranosides, which are easily convertible into L-arabino-hexos-5-uloses, can be prepared from β-D-galactopyranosides via peroxyacid oxidation in an alcoholic solvent of intermediate 4-deoxy-α-L-threo-hex-4-enopyranosides.

Meta-chloroperbenzoic acid can be used as a mild and selective reagent for the removal of the O-propenyl group in the deprotection sequence of allyl protected hydroxyl functions. Its use is illustrated in four synthetic pathways, leading, respectively, to methyl 3-0-acetyl-4- deoxy-6-0-( 1-methoxy-1-methylethyl)-α-L-threo-4-hexenopyranoside, to methyl 2-O-acetyl-3,4,6-tri-O-methyl-α- and β-D-galactopyranoside and to benzyl 6-O-allyl-3,4-0-isopropylidene-β-D-galactopyranoside.

Umbelliferose has been isolated from the fruits of CACHRYS FERULACEA (L.) Calestani and the sugar sequence has been determined by NMR spectroscopic 2D-COLOC technique. The method of identification of the trisaccharide, which occurs only in the Umbelliferae family and may have a chemotaxonomic significance, is described and briefly discussed.

A series of (η6-arene)(η4-cyclo-octa-1, 5-diene)ruthenium(0) complexes have been readily prepared by reaction of (η4-cyclo-octa-1,5-diene)(η6-cyclo-octa-1, 3, 5-triene)ruthenium(0) with arene compounds, under 1 atm H2[arene = C6H6, CH3 C6H5, 1, 4-Me2C6H4, 1,3,5-Me3C6H3, C2H5C6H5, Me2CHC6H5, Et2CHC6H5, C6H5(CH2)3 C6H5,C6H5C6H5, C2H5CH(Me)C6H5, Me2CHCH(Me)C6H5, NH2CH(Me)C6H5, CH3OC6H5, or CH3COC6H5]. These complexes react with aqueous HCI to give in almost quantitative yield the corresponding (η6-arene)-dichlororuthenium(II) complexes.

Kinetically controlled reaction of 4.5 equiv. of 2-methoxypropene with some alkyl α- and β- d -galactopyranosides gave the 2,3:4,6-di- O -isopropylidene derivatives in high yields (80–85%). With 2 equiv. of 2-methoxypropene, benzyl β- d -galactopyranoside gave the 4,6- and the 3,4-monoacetals in the ratio 30:1 together with ∼20% of the 2,3:4,6-diacetal. The structures of methyl 2,3:4,6-di- O -isopropylidene-α- and -β- d -galactopyranosides were determined by X-ray analysis. The former crystallised in the orthorhombic system, P 2 1 2 1 2 1 , with a = 5.503, b = 16.105, c = 16.822 A, and Z = 4, the latter in the monoclinic system, P 2 1 , with a = 10.400, b = 13.344, c = 11.647 A, β = 111.50, and Z = 4. The α anomer and the two molecules of the β anomer had the d -galactopyranoside and the 1,3-dioxane rings in twist-chair conformations and the dioxolane ring in a half-chair conformation. N.m.r. spectroscopy suggested the occurrence of similar conformations in solution.

The reaction of (1–2 : 5–6-η-cyclo-octa-1,5-diene)(1–6-η-cyclo-octa-1,3,5-triene)ruthenium with P(OMe)3 yielded the title compound which has been structurally characterized by X-ray diffraction studies. The complex crystallizes in the monoclinic space group P21/n with unit-cell dimensions a= 13.306(5), b= 9.628(3), c= 16.382(20)A, β= 111.62(6)°, and Z= 4. The co-ordination geometry around the ruthenium is a distorted square pyramid whose vertices are occupied by the phosphite ligand, the butadiene moiety of cyclo-octatriene, and the two double bonds of cyclo-octadiene.

New 4-(4-phenylsubstituted)-1,2,3-triazolacetic acid derivatives of general formula (I) were prepared by nucleophilic substitution, 1,3-dipolar cycloaddition and functional group interconversion reactions. These compounds were evaluated as in vitro prostaglandin synthesis inhibitors. Only the isomeric compounds (II c) and (III e), with a 4-aminophenyl substituent on the triazole ring, inhibit arachidonic acid-induced malondialdehyde formation in human platelets; (II c) and (III e) are as effective as aspirin.

Von einer Reihe uber das Nitroderivat (III) nach konventionellen Methoden dargestellten Phenyltriazolen, die allgemein die von Arachidonsaure induzierte Bildung von Malondialdehyd in menschlichen Blutkorperchen inhibieren, zeigen die Verbindungen (IV), (VII) und (VIII) eine entzundungshemmende Wirkung.

Treatment of O-protected 3,4-O-isopropylidene-β-d-galactopyranosides with tert-BuOK in N,N-dimethylformamide or methyl sulfoxide produces 4-deoxy-α-l-threo-hex-4-enopyranosides in good yields. The corresponding α-anomers and the non-O-protected derivatives are resistant to this treatment. Reaction of methyl 4-deoxy-2,6-di-O-methyl-α-l-threo-hex-4-enopyranoside with 3-chloroperbenzoic acid in CH2Cl2 gave a crystalline adduct that was hydrolyzed to 2,6-di-O-methyl-l-arabino-hexos-5-ulose.

The 6-O-trityl derivative of 2,3:5,6:3′,4′-O-isopropylidenelactose dimethyl acetal (1) was converted through an oxidation/oximation/reduction sequence involving the free 2-OH group of the D-galactose moiety into the protected disaccharide 5 in up to 75% yield. The complete deprotection of 5 produced the disaccharide 4-O-(2-acetamido-2-deoxy-β-D-talopyranosyl)-D-glucose (7a). The oxime LiAlH4 reduction step produced some unexpected side-products, the most abundant of which, the dimethyl acetal 9, deriving from cleavage of the D-glucose moiety, was formed only when the reaction was conducted in refluxing THF, but not when Et2O was used as the solvent.

3-(3,4-Dimethoxybenzylidene)phthalide gives, by reaction with glycine, a mixture of (E)- and (Z)-3-(3,4-dimethoxybenzylidene)phthalimidin-2-ylacetic acids (1), which upon hydrogenation afford 3-(3,4-dimethoxybenzyl)phthalimidin-2-ylacetic acid (2). This compound is cyclised by polyphosphoric acid to 13,13a-dihydro-10,11-dimethoxyisoindolo[1,2-b][3]benzazepine-5,8(7H)-dione (3). The ethylene acetal of (3)[(4)] gives, on reduction with lithium aluminium hydride followed by treatment with methyl iodide, 7,8,13,13a-tetrahydro-10,11-dimethoxy-6-methyl-8-oxo-5H-isoindolo[1,2-b][3]benzazepinium iodide ethylene acetal (6). This compound, by the action of alkali, is converted into a mixture of (Z)-5,6-dihydro-10,11-dimethoxy-6-methyldibenz[c,g]-azecin-8(7H)-one ethylene acetal (7), and 5,6,13,13a-tetrahydro-2,3-dimethoxy-7-methyl-5-oxo-8H-dibenzo-[a,g]quinolizinium iodide ethylene acetal (9). When either (6) or (9) are refluxed with sodium deuterioxide in deuterium oxide the methiodide (9)(formed or recovered) appears to be deuteriated at positions 6, 8, 13, and 13a. The methiodide (9) gives, by Hofmann elimination, (E)-5,6-dihydro-10,11-dimethoxy-6-methyldibenz[c,g]-azecin-8(7H)-one ethylene acetal (11), which may be transformed into 5,6,13,13a-tetrahydro-13a-hydroxy-2,3-dimethoxy-7-methyl-5-oxo-8H-dibenzo[a,g]quinolizinium chloride (14), and its ethylene acetal (13). The ketones derived from (6) and (9)[(8) and (10)] give, by treatment with alkali, the same relatively stable ylide (15) which rearranges on heating to 6,7,12,13-tetrahydro-6,13-imino-2,3-dimethoxy-14-methyldibenzo[a,e]-cyclononen-5-one (16).

A series of erythro- and threo-ethyl 3-hydroxy-2-methyl-3-(p-substituted phenyl)butyrates has been prepared The 1H n.m.r. spectra of these compounds and their use in assigning diastereoisomeric configurations are discussed