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The structural information of acetylcholine and its two agonists, nicotine and muscarine is obtained from the interpretation of infrared spectra recorded in the gas-phase or in low pH aqueous solutions. The shift of protonation site in nicotine ions is provided by the change of their infrared spectrum induced by hydration, whereas the structures of muscarine ions are only slightly influenced by the presence of water.

A general synthetic method fro pyrroquinolizidines (3,4,5,5a,6,7,8-heptahydropyrrolo[2,1,5-de]-quinozilines) by munchnone 1,3-dipolar cycloaddition is described. This method was used in the synthesis of an unnatural pyrroloqunilizidine homologue of myrmicarin 215B.

A new method for synthesis of N-protected staurosporinones is described. These staurosporinones are useful for the synthesis of indolo[2,3-a]pyrrolo[3,4-c]carbazole alkaloids and related compounds.

UV resonance Raman microspectroscopy was applied for a localization of the antiplasmodial naphthylisoquinoline alkaloid dioncophylline A in very low concentrations in different parts of the samples (e.g., in the roots) of the tropical liana Triphyophyllum peltatum. The application of resonance Raman microspectroscopy was characterized by a very high sensitivity and selectivity. It was possible to assign the resonance Raman spectra of dioncophylline A, dioncophylline C, and dioncopeltine A by means of a combination of NIR Raman spectroscopy and DFT calculations. The UV resonance Raman spectra of T. peltatum are very well resembled by the spectra of dioncophylline A, while they can be clearly distinguished from the spectra of dioncophylline C and dioncopeltine A. This distinction between the various naphthylisoquinolines was possible by the two modes at 1356 and 1613 [cm.sup.-1]. These two modes were assigned to C=C stretching and CH bending vibrations. The presented results of a highly sensitive and selective in situ localization of the active agent dioncophylline A in different parts of the plant material of T. peltatum are of high importance for the acquisition of new antimalarials and for plant science in general.

Batzelladine F was synthesized in enantioselective and stereoselective fashion in 15 steps. Also disclosed is the use of a chemical synthesis of complex guanidine alkaloids to prepare four stereoisomers of the presumed structure of batzelladine F.

The total synthesis of Hans Knoll Institute (HKI) 0231B that was completed in 12 linear steps and 15.6% overall yield is described. Studies regarding the construction and reactivity of the lactam acetal functionally present in HKI 0231A are also reported.

The beta-carbolinone core structure present in a variety of alkaloids was efficiently prepared from 5-oxo-1,2,3,5-terahydroindolozine-6-trifluoromethanesulfonate precursors. Allylation of methyl 6-hydroxy-5-oxo-1,2,3,5-tetrahydroindolizine-8-carboxylate gave the corresponding ethers, which subsequently underwent thermal Claisen rearrangement to afford the C-allyl products in high yields.

A flexible route to polyhydroxylated pyrrolidizines alkaloids is described, starting from commercially available N-Boc pyrrole and using a partial reduction as the key step. A first synthesis of hyacinthacine A1 is described that also confirmed the structure of the natural product, and a short stereoselective synthesis of 1-epiasutraline is also discussed.

Detailed experimental approaches toward the pentacyclic Stemona alkaloids tuberostemonine and didehydrotuberostemonine and the close analogue 13-epituberostemonine are described. Structural analysis by density functional theory (DFT) methods revealed that the ease of oxidation of the natural product is likely due to the conformational preferences of the pyrrolidine and the fused cyclohexane rings.

Two natural alkaloids, oncinotine and neooncinotine are synthesized with the help of efficient ring-closing metathesis (RCM) reactions. Two different methods are developed to achieve the Michael addition of acrylamide and two amidations of succinic anhydride and Grubbs catalyst are used to form the 17- and 18-membered lactams in 50% and 68% yields, respectively.

CD, NOESY and molecular modeling analysis are used for determining the absolute configuration and conformation of two novel alkaloids called manadomanzamines A and manadomanzamines B. Manadomanzamines A and B shows strong activities against Mycobacterium tuberculosis, human immunodeficiency virus (HIV-1) and AIDS opportunistic fungal infections.

Several analyses are conducted to explain the different crystal structures exhibited by the unliganded Aspergillus fumigatus FtmPT1. The application of the fungal indole prenyltransferases as modifiable bioreactors for the catalysis of highly specific prenyl transfer reactions is also demonstrated.

The structural determination of A polyaromatic alkaloid, aplidiopsamine A isolated from the temperate Australian ascidian, Aplidiopsis confluata is described. Aplidiopsamine A is the first alkaloid which exhibited significant inhibition of growth of chloroquine resistant and sensitive strains of the malaria parasite, Plasmodium falciparum, and minimal toxicity toward human cells.

A variety of chiral nitrogen bases as catalysts, mainly derived from cinchona alkaloids, in the presence of various protic nucleophiles as proton source are utilized to perform enantioselective protonation of silyl enol ethers. The synthetic utility of this organocatalytic protonation was demonstrated during the preparation of two homoisoflavones, isolated from Chlorophytum Inornatum and Scilla Nervosa, which are obtained with 81% and 78% ee, respectively.

The stereocontrolled total synthesis of clavicipitic acid and aurantioclavine from a common azepino[5,4,3-cd]-indole intermediate is described. The study results identified mis-assigned configurations of the synthesized clavicipitic acids during course of reaction process and recommended to switch the trans and cis configuration assignments of the synthesized clavicipitic acids and their derivatives.

The first total syntheses of the Lycopodium alkaloids (+)-nankakurine A, (+)-nankakurine B and the originally supported structure of nankakurine A is feature a demanding intramolecular azomethine imine cycloaddition as the key step is reported. The reaction generated the octahydro-3,5-ethanoquinoline moiety and installed the correct relative configuration at the spiropiperidine ring juncture.

The first total synthesis of (+)-lycoflexine, a constituent of Lycopodium clavatum var. inflexum, is achieved in eight steps. The synthesis has included a tandem Sakurai/aldol sequence, a novel hydroboration/oxidation procedure, a deprotection/transannular Mannich reaction, and a tandem catalysis cascade combining an enyene ring-closing metathesis and a selective hydrogenation.

The seven step total synthesis of the bridge-fused Aspidosperma indole alkaloid ([plusmn])-subincanadine F is presented. The synthetic application of a titanium-mediated intramolecular nucleophilic acyl substitution (INAS) reaction for the construction of the bridge-fused ring system is demonstrated.

The asymmetrical total synthesis of (+)-perophoramidine is achieved, where the key steps have depended on an asymmetric biomimetic Diels-Alder reaction between the in situ-generated chiral diene T-24 and the substituted tryptamine. The absolute configuration of (+)-perophoramidine is analyzed by X-ray crystallographic analysis of the chiral intermediate and the comparison of the rotation of synthetic (+)-perophoramidine with that of the natural product.

The application of two newly developed reactions to natural product synthesis, where the first method has involved a 6-endo-trig cyclization to prepare a versatile chiral enaminone building block and the second is a direct C-H arylation reaction, is described. Arylindolizidine alkaloids (+)-antofine and (+)-ipalbidine are prepared only in 8 steps by using these new methods.

2-Substituted derivative of L-tryptophan has undergone conversion to a prephalarine structure in a single step. The reaction has occurred in a diastereoselective fashion, which has led to the naturally occurring version of the alkaloid phalarine.

Two new bisindole alkaloids, bisnicalaterines B and C consisting of an eburnane and a corynanthe type, are isolated from the bark of Hunteria zeylanica and their absolute structures are determined. Bisnicalaterines B and C have displayed potent vasorelaxant activity on isolated rat aorta.

The first total synthesis of (+)-sieboldine A completed in 20 steps from easily available (3aS,6aR)-3,3a,4,6a-tetrahydro-2H-cyclopenta[b]furan-2-one is reported. The key steps in the synthesis include a pinacol-terminated 1,6-enyne cyclization reaction to form the cis-hydrindanone core, formation of the spiro tetrahydrofuran ring by stereoselective DMDO oxidation of tricyclic dihydropyran intermediate and formation of the unprecedented N-hydroxyazacyclononane ring by cyclization of a thioglycoside precursor.

The total synthesis of (+)-fawcettimine is completed in a stereoselective manner starting from the oxatricyclo[7.3.0.[0.sup.1,5]]dodecanedione derivative. The construction of the azonane framework by the intramolecular Mitsunobu reaction is the crucial step in the total synthesis and also the total synthesis of (+)-lycoposerramine-B is achieved via the common synthetic intermediate.

An efficient total synthesis of notoamide J, a new prenylated indole alkaloid and potential biosynthetic precursor is presented. The synthesis starting from L-proline and a substituted tryptophan derivative employs an oxidation and pinacol rearrangement for the formation of the oxindole in the final step.

A newly designed synthetic strategy for construction of the heptacyclic marine fungal alkaloid ([plusmn])-communesin F, is described. The key step in the reaction include an intramolecular Heck cyclization of a tetrasubstituted alkene to generate a tetracyclic enamide bearing one of the quaternary carbon centers (C7) of the alkaloid.

A fully diastereoselective total synthesis of the lycorenine-type Amaryllidaceae alkaloid ([plusmn])-divonine is described by a route that has used a biomimetic ring-switch from a lycorine-type progenitor.

A total synthesis of the Aspidosperma alkaloids (+)-fendleridine and (+)-1-acetylaspidoalbidine is described, which has provided access to both enantiomers of the natural products and has established their absolute configuration. The final tetrahydrofuran bridge is installed in one step, which has enlisted an intramolecular alcohol addition to an iminium ion generated by nitrogen-assisted opening of the cycloadduct oxido bridge, with a modification that has permitted release of useful functionality at the cleavage termini.

Synthesis of two unnatural alkaloids while attempting to initiate a plausibly biomimetic cyclization approaching to (-)-lycojapodine A, are reported. The obtained alkaloids are one of the newest Lycopodium alkaloids.

The first total synthesis of (-)-fructigenine A, and a novel approach to (-)-5-N-acetylardeemin through a common imine intermediate are described. The key steps in the reaction include highly enantioselective preparation imine intermediate, reductive cyclization (RC), and regioselective oxidation and a novel assembly of the pyrazino ring of obtained alkaloids via Ugi three-component reaction/cyclization of imine with the corresponding amino acid and isonitrile.

The cyclization of nitrogen-centered radicals onto silyl enol ethers is a good method for preparing polyhydroxylated alkaloids as the 2-hydroxymethylpyrrolidine core is accessed from a linear precursor. The studies have shown that cyclization diastereoselectivities of substrates with alkyl or aryl substitution are excellent regardless of olefin geometry or substitution pattern.

A flexible method is described for the diastereoselective total synthesis of the pyrrolizidine alkaloids uniflorine A, casuarine, australine, and 3-epi-australine and the unnatural epimer 3,7-di-epi-australine from a common chiral 2,5-dihydropyrrole precursors.

The various processes and approaches involved in the total synthesis of the N,C-coupled naphthylisoquinoline alkaloids ancistrocladinium A and B and related analogues are explained. The various properties and applications of these compounds are also discussed.

The asymmetric dihydroxylation of amino-functionalized vinyl sulfone is utilized for the 3-step synthesis of 3-hydroxylpiperidine in 86% enantiomeric excess. The obtained enantiomerically enriched building block is further utilized to prepare the naturally occurring antimalarial alkaloid febrifugine and its antiangiogenic analogue, halofuginone.

An appropriate unsaturated phenylglycinol-derived oxazolopiperidone lactam is used for preparing of (-)-episilicine, where the key steps are a stereoselective conjugated addition, a stereoselective alkylation and a ring-closing metathesis reaction. This is the first enantioselective total synthesis of an alkaloid of the silicone group.

The article presents a new approach, which can be used for the development of highly enantioselective [alpha]-amination of oxindoles that are normally characterized by the cinchona alkaloid. The synthesis reaction is shown to be extremely general and simple, hence giving high yields of the desired product.

The total syntheses of cyclic nitrone-containing phlegmarine-type Lycopodium alkaloids, lycoposerramines-X and -Z is described. The reaction used starting materials from (R)-3-methylcyclohexanone via Pd-catalyzed Suzuki-Miyaura coupling, Johnson-Claisen rearrangement, stereoselective hydroboration-oxidation reaction, and Mitsunobu reaction to establish absolute configuration of alkaliod structures.

An indole-templated ring-closing metathesis or a 2-indolylacyl radical cyclization has represented the major steps of two alternative approaches developed to assemble the tricyclic ABC substructure of the indole alkaloid apparicine. An intramolecular vinyl halide Heck reaction has accomplished the closure of the strained 1-azabicyclo[4.2.2] decane framework of the alkaloid with concomitant incorporation of the exocyclic alkylidene substituents.

The synthesis of all four members of the louisianin family is described from 1,2,4-triazine and via a common tetrasubstituted pyridine intermediate. The analysis has included the preparation of louisianin B in both racemic form and as the (-)-enantiomer.

The [Rh.sub.2][(MPPIM).sub.4]-catalyzed intramolecular C-H insertion reaction of (S)- and (R)-1-benzyl-5-([alpha]-diazoacetoxy)piperidin-2-one and (S)-1-benzyl-4-([alpha]-diazoacetoxy)pyrrolidin-2-one has proceeded with high regioselectivity and cis-diastereoselectivity to produce chiral nonracemic bicyclic lactam lactones (BLLs). The utility of the BLLs as chiral building blocks in alkaloid synthesis is exemplified by the preparation of (8S,8aS)-octahydroindolizidin-8-ol and (1S,8aS)-octahydroindolizidin-1-ol.

Asymmetric total synthesis and revised structure of cephalezomine H, cephalotaxus alkaloids, is presented. The originally assigned and revised structure of cephalezomine H is synthesized from the key intermediate for the synthesis of (-)-cephalotaxine.

The first total synthesis of (+)-villatamines A and B achieved in six and five steps, respectively is reported. The results revealed the presence of the stereogenic center for the two naturally occurring alkaloid which have an (S)-configuration.

The protective-group-free total synthesis of ([plusmn])-subincanadine F from the commercially available tryptamine in 33% overall yield is presented. The 7 step reaction involved chemoselective Dieckmann condensation as the key step.

An approach that involved construction of the fully substituted asymmetric center at an early stage is used to describe the total synthesis of the marine alkaloid halichlorine. A formal synthesis of (+)-halichlorine based on the development of a general method for preparation of optically pure piperidines which involved Claisen rearrangement of a 4-vinyloxy-3,4-dihydro-2H-pyridine-1-carboxylic acid benzyl ester as key step is also reported.

An intramolecular 1,4-dipolar cycloaddition of a cross-conjugated heteroaromatic betaine was used to develop an efficient stereocontrolled route to the isoschizozygane alkaloid core. The modified version of the method could also be used for synthesis of the hexacyclic framework of the shizozygane alkaloid ([plusmn])-strempeliopine.

An enantioselective total synthesis of the Strychnos alkaloid (+)-minfiensine is described. The preparation has included a new enantioselective organocatalytic Diels-Alder/amine cyclization sequence to build the central tetracyclic pyrroloidoline framework from commercial materials and a 6-exo-dig radical cyclization to forge the final piperidinyl ring system.

Several quantum chemical calculations are conducted to explain the selective organocatalytic activity of the various cinchona alkaloids. The mechanisms employed in the reaction of these alkaloids with quinuclidine ring of the benzyl bromide are also explained.

Several density functional theory analyses are conducted to examine the mechanisms involved in the [1,3]- of allylic trichloroacetimidates, which are catalyzed by cinchona alkaloids. The different pseudopericyclic transition states that lead to the rearranged products are also studied.

The application of the various ring-expansion reactions of [gamma]-silyloxy-[gamma]-lactams for the synthesis of different medium-sized nitrogen heterocycles is demonstrated. The lactams used in the discussed process is shown to be formed by the annulations reactions of the allylic silanes.

Charge neutral TpMo[(CO).sub.2](5-acyloxy-[[eta].sup.3]-pyranyl) and TpMo[(CO).sub.2](5-acyloxy-[[eta].sup.3]-pyridinyl) scaffolds have undergone a novel intermolecular 'homo-[S.sub.N]2'-like' reaction with a variety of carbon nucleophiles. An enantiocontrolled total synthesis of the antimalarial alkaloid (+)-isofebrifugine is achieved by using the reaction cascade.