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The three novel 19(10→9)abeo-8α,9β,10α-euphane (reissantane) triterpenoids isolated from Reissantia indica(Celastraceae) and related to reissantioloxide (reissantenol oxide)(1) have been shown to be 24-oxoreissant-5-ene-3β,25-diol (2), 3-oxoreissant-5-ene-24β,25-diol (3), and reissant-5-ene-3β,24β,25-triol (4). A possible biosynthetic relationship for reissantane, D : B-friedo-oleanane, D : A-friedo-oleanane, and quinone-methide triterpenoids which occur in R. indica is presented.

The benzene extract of the inner stem bark of Kokoona zeylanica Thwaites (Celastraceae) contains twelve D : A-friedo-oleananes of which nine are new. The new triterpenes have been classified under three series; kokoonol (3,27-dioxy and 3,21,27-trioxy), zeylanol (3,6-dioxy and 3,6,21-trioxy), and kokzeylanol (3,6,27-trioxy and 3,6,21,27-tetraoxy). Six of these triterpenes belonging to the kokoonol and zeylanol series have been identified as 27-hydroxy-D : A-friedo-oleanan-3-one (4)(kokoonol), 27-hydroxy-D : A-friedo-oleanane-3,21-dione (5)(kokoononol), 21α,27-dihydroxy-D : A-friedo-oleanan-3-one (6)(kokoondiol), 6β-hydroxy-D : A-friedo-oleanan-3-one (21)(zeylanol), 6β-hydroxy-D : A-friedo-oleanane-3,21-dione (22)(zeylanonol) and 6β,21β-dihydroxy-D : A-friedo-oleanan-3-one (23)(zeylandiol), by spectroscopic methods and chemical interconversions. The biosynthetic significance of 6-hydroxy-D : A-friedo-oleananes is discussed.

Formation of the photoproducts (10) and (12) and chemical and spectroscopic evidence suggest that kokoononol obtained from Kokoona zeylanica is 27-hydroxyfriedelane-3,21-dione (1); kokoondiol and kokoonol have been identified as 21α,27-dihydroxyfriedelan-3-one (2) and 27-hydroxyfriedelan-3-one (3), respectively, by chemical conversions.

Protection of the ring B diene system of ergosterol by (i) a two-step addition of the elements of water across the 5,6-double bond, (ii) formation of the 4-phenyl-1,2,4-triazoline-3,5-dione adduct, or (iii) formation of the iron tricarbonyl adduct by treatment with p-methoxybenzylideneacetonetricarbonyliron, allowed selective reduction of the 22,23-double bond by catalytic or, as appropriate, ionic hydrogenation. Regeneration of the 5,7-diene system in each case gave a high yield of 22,23-dihydroergosterol.

The isolation of chitranone (3), zeylanone (4), maritinone (5), 2-methylnaphthazarin (6), plumbazeylanone, and a new naphthoquinone, methylene-3,3′-diplumbagin (7) from the phenolic fraction of the light petroleum extract of the roots of Plumbago zeylanica(Plumbaginaceae) is reported. The dimethyl ether of the new quinone has been synthesized from plumbagin methyl ether.

Two efficient routes to bis-(2-arylethyl)amines have been developed by using regiospecific alkylation of dialkylnitrosamine anions and homologation of aromatic aldehydes with methoxyacetonitrile anion as the respective key steps. The hitherto uncharacterised 1,3-diaryl-2-azonia-allene ions have been prepared in isolable form. Attempted insertion of C1 fragments into these systems as a third route to the title compounds failed.

The structure and stereochemistry of reissantioloxide, a triterpene epoxide with a novel (24S)-24,25-epoxy-19(10 → 9)abeo-8α,9β,10α-euph-5-en-3β-ol skeleton isolated from Reissantia indica, have been established from spectral data and single-crystal X-ray analysis.

Testosterone and 19-norethisterone are smoothly esterified by some hindered carboxylic acids in pyridine containing benzenesulphonyl chloride.

Zeylasterone, the first of a novel series of natural phenolic nortriterpenes from Kokoona zeylanica(Celastraceae) and ‘ kokum soap ’ has been shown to be 29-methyl hydrogen 2,3-dihydroxy-6-oxo-D:A-friedo-24-noroleana-1,3,5(10),7-tetraene-23,29-dioate (3) on the basis of spectroscopic and chemical evidence. Trimethylzeylasterone (8) has been synthesized from pristimerin, a quinone methide present in K. zeylanica and ‘ kokum soap ’. The biosynthetic importance of some triterpenoids of K. zeylanica is discussed.

The three new phenolic nortriterpenes, demethylzeylasteral, zeylasteral, and demethylzeylasterone, isolated from Kokoona zeylanica(Celastraceae), have been shown to be 2,3-dihydroxy-6,23-dioxo-D:A-friedo-24-noroleana-1,3,5(10),7-tetraen-29-oic acid (5), its methyl ester (6), and 2,3-dihydroxy-6-oxo-D:A-friedo-24-noroleana-1,3,5(10),7-tetraene-23,29-dioic acid (7), respectively. The structure of the new phenolic (9 → 8)-D:A-friedo-24-noroleanane triterpene obtained from ‘kokum soap’ has been established as 23-oxoisopristimerin III (11) on the basis of spectroscopic evidence. The biosynthetic significance of 23-oxoisopristimerin III is discussed.