Venkatachalam S. Giri

Versatile Reagent for Reduction of Azides to Amines

Abstract Triphenylphosphine (TPP) in refluxing methanol effectively reduces a variety of azides 1a–k to amines 2a–k in very good yields.

Microwave Assisted Pictet–Spengler and Bischler–Napieralski Reactions

Abstract Pictet–Spengler and Bischler–Napieralski reaction products have been prepared–using microwave irradiation on silicagel support under solvent free condition. Microwave assisted reactions have resulted in better yields of the desired products than prepared under conventional conditions.

Fe-HCl: An Efficient Reagent for Deprotection of Oximes as well as Selective Oxidative Hydrolysis of Nitroalkenes and Nitroalkanes to Ketones

Abstract Fe‐HCl mixture was found to selectively perform oxidative hydrolysis of the nitroalkenes 1a–j and nitroalkanes 2a–j to the ketones 3a–j. Also, the reagent was observed to deprotect the oximes 7a–j to carbonyl compounds 8a–j in excellent yields.

Anti-leukemic activity of Wattakaka volubilis leaf extract against human myeloid leukemia cell lines.

ETHNOPHARMACOLOGICAL RELEVANCE Wattakaka volubilis has been traditionally used in Ayurvedic medicine in India for treatment of several ailments such as bronchial asthma, inflammations, tumors, piles, leucoderma, application to boils, rat bite etc. AIM OF THE STUDY The present study was designed to investigate anti-leukemic activity of the crude aqueous methanolic extract and to identify active compounds from the leaves of Wattakaka volubilis. MATERIALS AND METHODS The leaves of Wattakaka volubilis were extracted with aqueous methanol. Liquid-liquid fractionation of the crude methanolic extract with different organic solvents was done and the fractions were screened for in vitro anti-leukemic activity using different leukemic cell lines. The active fractions were then subjected to chromatographic separation for isolation of bioactive compounds. Structure of isolated compound was elucidated by spectroscopic methods. The in vitro anti-leukemic activities of different extracts of the leaves and isolated compound WVP were studied in U-937, HL-60 and K-562 cell-lines by using cell count, MTT [(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide] and DNA laddering assays, flow-cytometric and confocal microscopic techniques. RESULTS Kaempferol-3-O-[α-l-rhamnopyranosyl-(1→4)-O-α-l-rhamnopyranosyl-(1→6)-O]-β-d-glucopyranoside (WVP) was isolated from crude leaves extract of Wattakaka volubilis. Both the n-butanolic extract (WVB) of Wattakaka volubilis and its isolate WVP were found to be responsible for in vitro anti-leukemic activity. The IC(50) values of WVB were found be 120, 100 and 50(μg/ml) in U937, K562, and HL-60 cell lines, respectively. Whereas, the pure isolate WVP exhibited anti-leukemic activity with IC(50) values of 13.5, 10.8, and 13.2(μg/ml) in U937, K562, and HL-60 cell lines, respectively. The flow-cytometric analysis confirms that the cell cycle arrest occurs at G1 phase in case of U937 and K562 cell lines and G2/M phase in case of HL60 cell lines. Similarly both confocal microsocopic analysis and DNA laddering assay confirm the apoptosis and cell cycle arrests of leukemic cells. CONCLUSION The overall results provide evidence for the ethnopharmacological relevance for use of the plant Wattakaka volubilis in developing novel agents for the treatment of leukemia.

Antioxidant and antibacterial activities of bark extracts from Commiphora berryi and Commiphora caudata

This study investigates the in vitro antioxidant and antimicrobial activities of eight extracts obtained from the dried barks of Commiphora berryi and Commiphora caudata (Burseraceae). The radical scavenging activity was assessed by 1,1-diphenyl-2-picryl hydrazyl (DPPH) and nitric oxide assays. The methanolic extracts of C. berryi and C. caudata showed significant DPPH radical scavenging activity, with IC50 values of 26.92 and 21.16 µg mL−1, respectively, and low radical scavenging activity against the nitric oxide assay. The antimicrobial activity of the plants was tested against the Gram-positive and Gram-negative bacteria. The ethyl acetate, chloroform and petroleum ether extracts of C. berryi showed good antibacterial activity against Pseudomonas aeruginosa, with a minimum inhibitory concentration (MIC) of 0.26 mg mL−1, whereas the ethyl acetate and methanol extracts of C. caudata showed moderate antimicrobial activity with an MIC of more than 2.0 mg mL−1 against P. aeruginosa compared to the petroleum ether and chloroform extracts, which showed an MIC of 1.1 mg mL−1. The methanolic extracts of C. berryi and C. caudata also showed moderate cytotoxic activity against a human mammary carcinoma cell line (MCF-7), with values IC50 of 82.6 and 88.4 µg mL−1, respectively.

MICROWAVE ASSISTED McFADYEN–STEVENS AND HUANG–MINLON REACTIONS

ABSTRACT Microwave irradiation has been employed in McFadyen–Stevens reaction to convert p-toluenesulfonyl hydrazides 1 to the aldehydes 2. Also, microwave has been applied in Huang–Minlon reduction of carbonyl compounds 3 to the corresponding hydrocarbons 4.

Synthesis of the alkaloids (±)-normalindine and (±)-norisomalindine

The alkaloids normalindine (3) and norisomalindine (4) have been synthesised via the β-carbolinium salt (7) by pivaloyl chloride induced cyclization and subsequent reduction with sodium cyanoborohydrite

Synthesis of the Alkaloid Nauclefidin

Abstract Synthesis of the alkaloid nauclefidine (1) through the intermediacy of the quinolizine 4 is described. McFadyen-Stevens reaction of the corresponding tosyl hydrazide (6) of 4 afforded 1.

Convenient Procedure for Dethioketalisation in Nitrogen Heterocycles

Abstract Regeneration of Carbonyl compounds from the corresponding thioketals in nitrogen heterocycles have been effected using Dowex 50W acidic catalyst in reasonable yields.

The oxindole alkaloids ofVinca elegantissima Hort

AusVinca elegantissima Hort. var.V. major wurden zwei neue Oxindolalkaloide, Elegantissin (3) und Isoelegantissin (4) isoliert und ihre Konstitution aus den spektralen Eigenschaften und der Isomerisierung zu den bekannten Alkaloiden Majdin (2) und Isomajdin (1) abgeleitet.