Ashit K. Ganguly

Solution- and solid-phase synthesis of enantiomerically pure spiro oxindoles

A convenient synthesis of enantiomerically pure oxindoles using a three component reaction involving 1:3 dipolar cycloaddition reaction has been achieved using solution and solid phase chemistry.

Design, Synthesis, and X-ray Crystallographic Analysis of a Novel Class of HIV-1 Protease Inhibitors

In the present paper, design, synthesis, X-ray crystallographic analysis, and HIV-1 protease inhibitory activities of a novel class of compounds are disclosed. Compounds 28-30, 32, 35, and 40 were synthesized and found to be inhibitors of the HIV-1 protease. The crucial step in their synthesis involved an unusual endo radical cyclization process. Absolute stereochemistry of the three asymmetric centers in the above compounds have been established to be (4S,2R,3S) for optimal potency. X-ray crystallographic analysis has been used to determine the binding mode of the inhibitors to the HIV-1 protease.

Synthesis of heterocyclic compounds using radical reactions

A generalised radical reaction has been used to synthesise heterocyclic compounds which could serve as ligands for drug discovery. Attempt also have been made to rationalise the formation of oxidation products formed during TBTH reaction.

Highly stereoselective access to novel 2,2,4-trisubstituted tetrahydrofurans by halocyclization: Practical chemoenzymatic synthesis of Sch 51048, a broad-spectrum orally active antifungal agent

A convenient synthesis of (−)-(2R)-cis-tosylate 2 is reported via stereoselective 5-exo iodocyclization of the optically active 2,2-disubstituted olefin 9a. Enzymatic desymmetrization of the homoallylic diol 4 with Novo SP435 allowed optimal pro-(S) selectivity to provide the desired (−)-(S)-monoacetate 9a. Under the irreversible reaction conditions, the presence of a bulky aryl substituent on the 2,2-disubstituted olefin seems to determine stereochemical outcome of these halocyclizations.

Enantioselective syntheses of carbocyclic ribavirin and its analogs: linear versus convergent approaches

Abstract The first enantioselective syntheses of carbocyclic ribavirin by both convergent and linear approaches are described. The linear approach from chiral nonracemic 2-azabicyclo[2.2.1]hept-5-en-3-one proves to be a highly efficient route to carbocyclic analogs of ribavirin.

Synthesis of 14-α-aminomethyl substituted lanosterol derivatives; inhibitors of fungal ergosterol biosynthesis

Several 14-α-aminomethyl-substituted lanosterol derivatives have been synthesized involving a complete Δ7,8to Δ8,9isomerization; these compounds are inhibitors of fungal ergosterol biosynthesis and are active against intact Candida and dermatophyte strains.

Stereochemistry at C-3 of evernitrose: a fallacy in the determination of stereochemistry at quaternary centres using nuclear magnetic resonance spectroscopy. X-Ray crystal structure of methyl 3-acetamido-2,3,6-trideoxy-3-c,4-O-dimethyl-L-xylo-hexopyranoside

Single crystal X-ray analysis of the title compound (8) is reported which establishes the stereochemistry at C-3 of evernitrose.

Structure of halomicin B

The antibiotic halomicin B has been shown by spectroscopic and chemical means to have the structure (1).

Hydrolysis products of everninomicin B

Hydrolysis of everninomicin B yields a mixture from which a heptasaccharide, everheptose B, has been isolated; everheptose B contains a new sugar, D-evalose, the structure and absolute stereochemistry of which has been established.

Structure and absolute stereochemistry of evermicose

Evermicose, an hydrolysis product of everninomicin B and D, has been shown to be 3-C-methyl-2,6-dideoxy-D-arabinohexose, or D-3-epimycarose.