D. S. Bhakuni

Aporphine alkaloids of annona squamosa

Abstract The aporphine alkaloids anonaine, roemerine, norcorydine, corydine, norisocorydine, isocorydine and glaucine have been isolated from Annona squamosa .

Roseoside-A C13 glycoside from Vinca Rosea

Abstract Roseoside, a C13 glycoside isolated from Vinca rosea has been assigned the structure and stereochemistry (1).

An antiviral sphingosine derivative from the green alga Ulva fasciata

A fraction showing in vitro and in vivo antiviral activity was isolated from the green alga Ulva fasciata found in the Indian Ocean off the West coast of India. The structure of its major component was established to be N-palmitoyl-2-amino-1,3,4,5-tetrahydroxyoctadecane on the basis of spectral studies.

Naphthaquinones of Arnebia nobilis

Abstract Silica gel chromatography of the fraction from Arnebia nobilis possessing antibiotic and anticancer activities has yielded three new naphthaquinones, 5,8-dihydroxy-2-(1′-β,β-dimethylacryloxy-4′-methylpentyl)-1,4-naphthaquinone, 5,8-dihydroxy-2-(4′-hydroxy-4′-methylpentyl)-1,4-naphthaquinone and 2-(1′-acetoxy-4′-hydroxy-4′-methylpentyl)-5,8-dihydroxy-1,4-naphthaquinone, along with alkannin [5,8-dihydroxy-2-(1′-hydroxy-4′-methylpent-3′-enyl)-1,4-naphthaquinone], 5,8-dihydroxy-2-(1′-β,β-dimethylacryloxy-4′-methylpent-3′-enyl)-1,4-naphthaquinone and 2-(1′-acetoxy-4′-methylpent-3′-enyl)-5,8-dihydroxy-1,4-naphthaquinone, which were reported earlier.

The Reaction of Acyloxysulfonium Salt with Cyclic Enol Ethers: Novel Synthesis of Vinyl Sulfides

Abstract The reaction of 2,3-dihydrofuran (1), dihydropyran (2) and indole (8) with acyloxysulfonium salt (3) and Methyl amine furnished vinyl sulfides 6, 7 and 10 respectively in very good yields.

Diels-Alder reaction of in-situ generated 2-methoxycarbonyl-p-quinone with D-glucose based dienes: a new approach to forskolin

Abstract Diels-Alder reaction of 2-methoxycarbonyl- p -quinone 3 with D -glucose based dienes 4 ( a – h ) furnished cis -adducts 10 ( a – h ) in a stereo- and regiospecific manner. Chemical transformation of 10 afforded 11 – 15 . Compounds 12 , 13 and 15 are key intermediates in the proposed synthesis of forskolin.

The aporphine alkaloids of Litsea glutenosa

Abstract The aporphine alkaloids, norboldine, boldine, laurotetanine, N-methyllaurotetanine, actinodaphnine and N-methylactinodaphnine have been isolated from Litsea glutenosa var. glabraria Hook.

Synthesis of tylophorine

Abstract A biogenetic type of synthesis of tylorphorine 12 (3.8% yield, established by a radio-dilution method) was achieved by ferricyanide oxidation of 6,7-di(3-hydroxy-4-methoxyphenyl)-6,7-dehydroindolizidine 10 .

The alkaloids of croton sparsiflorus

Abstract Three proaporphine bases provisionally designated crotsparine (I), m.p. 193–194°, N -methyl-crotsparine (III), m.p. 223–225°, and N,O -dimethylcrotsparine (IV), m.p. 125–127°; two dihydroproaporphines, crotsparinine (II), m.p. 184–185°, and N -methylcrotsparinine (V), m.p. 160–161°, and the known aporphine alkaloid, sparsiflorine (X), m.p. 229–231°, have been isolated from Croton sparsiflorus Morong and their structures and stereochemistry assigned. N -Methylcrotsparine is of biological interest as a hypotensive agent.

Ursane triterpenoids from Nepeta eriostachia

Abstract From the aerial parts of Nepeta eriostachiya two rare ursane triterpenoids, 2α,3α-dihydroxyurs-12-en-28-oic acid and 2α,3β-dihydroxyurs-12-en-28-oic acid, together with a new triterpene, nepetoic acid identified as 2α-methoxy-3β-hydroxyurs-12-en-28-oic acid were isolated as their methyl esters. Their structures were established by chemical and spectroscopic means.