T.R. Govindachari

Alkaloids of Mappia foetida

Two alkaloids have been isolated from Mappia foetida Miers. The major alkaloid is camptothecin (Ia) and the minor alkaloid has been shown by spectral studies to be the hitherto unknown 9-methoxycamptothecin (Ic).

Structure of parthenolide

Abstract New degradation experiments and NMR data on the sesquiterpene lactone isolated from the roots of Michelia champaca and identified as parthenolide have led to revision of the structure I originally proposed by Sorm et al. to that depicted by IV.

Triterpenes of calophyllum inophyllum linn

Friedelin (Ia) and three new triterpenes of the friedelin group have been isolated from the leaves of Calophyllum inophyllum. The three new compounds, canophyllal (Ib), canophyllol (Ic) and canophyllic acid (IVa) have been inter-related and their structures established by a direct correlation with oleanenic lactone (XI).

Chemical constituents of Cleistanthus collinus (Roxb.)

Ellagic acid, diphyllin (IIIa) and two new lignan lactones, cleistanthin and collinusin, have been isolated from Cleistanthus collinus (Roxb.). Cleistanthin and collinusin have been shown to have structures IIIc and VI respectively.

Isolation and structure of two new dihydroisocoumarins from Kigelia pinnata

Two new dihydroisocoumarins (IIIa and IVa) have been isolated from Kigelia pinnata and their structures established. Stigmasterol, β-sitosterol, lapachol and 6-methoxymellein were also identified in the roots and bark.

Ishwarane and aristolochene, two new sesquiterpene hydrocarbons from Aristolochia indica☆

From the roots of Aristolochia indica, two new sesquiterpene hydrocarbons, named ishwarane and aristolochene, have been isolated and assigned strutures II and III respectively.

Chemical constituents of glochidion hohenackeri

From the bark and roots of Glochidion hohenackeri (Euphordiaceae), in addition to the known 3-epi-lupeol, two new triterpenes glochidone and glochidiol have been isolated and assigned structures I and VIIIa respectively. The stereochemistry of the hydroxyl groups in glochidiol has been determined by the partial synthesis of three of the four possible stereoisomers of the dihydrodiol diacetate (Vd, VId and VIId) which all differ from dihydroglochidiol diacetate (VIIId).

Ancistrocladine, a new type of isoquinoline alkaloid from Ancistrocladus heyneanus☆

A new alkaloid, ancistrocladine, isolated from Ancistrocladus heyneanus wall., has been assigned the structure 1 based on spectral and synthetic evidence of the degradation products.

Chemical examination of Tylophora asthmatica—II

Abstract Tylophorine has been degraded to a compound, identified as 2:3:6:7-tetramethoxy-9-methylphenanthrene. In conjunction with other degradation results and biogenetic considerations, tylophorine is now formulated as 2:3:6:7-tetramethoxyphenanthro(9:10:6′:7′)indolizidine. A synthesis of the basic ring system, phenanthro-(9:10:6′:7′)indolizidine, present in tylophorine has been achieved.

Minor alkaloids of Tylophora asthmatica : Revised structure of tylophorinidine☆

Abstract The structure of the phenolic alkaloid tylophorinidine, isolated from Tylophora asthmatica , has been shown to be 2 . Two other minor alkaloids isolated from the plant have been shown to be d -septicine ( 11 ) and d -isotylocrebrine ( 14 ).