✦ LIBER ✦

Synthesis of tritium labelled precocenes

✍ Scribed by A. Banerji; N. C. Goomer

Publisher: John Wiley and Sons
Year: 1981
Tongue: French
Weight: 200 KB
Volume: 18
Category: Article
ISSN: 0022-2135
DOI: 10.1002/jlcr.2580181205

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✦ Synopsis

Abstract

Regiospecific syntheses of tritium labelled precocene I (5a) and precocene II (5b), the antijuvenile hormones, have been accomplished. The syntheses involved condensations between 2‐hydroxyacetophenones (1) with acetone‐T to give cross condensation products 2 which on cyclodehydration furnished 2,2‐dimethyl‐4‐chromanones‐(2‐gem dimethyl‐T) (3). Reduction of 3 with lithium aluminium hydride gave chroman‐4‐ols (2‐gem dimethyl‐T) (4). Dehydration of 4 furnished 2,2‐dimethyl‐ chromenes‐ (2‐gem dimethyl‐T) (5). Starting with appropriate acetophenones and acetone‐T, precocene I (7‐methoxy‐2,2‐dimethylchromene) and precocene II (6, 7‐dimethoxy‐2, 2‐dimethylchromene) labelled with tritium in the 2‐gem dimethyl positions, have been synthesised in high chemical as well as radiochemical yields.

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