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14 C‐labelling of optically active fenvalerate, (S)‐α‐cyano‐3‐phenoxybenzyl (s)‐2‐(4‐chlorophenyl)‐3‐methylbutyrate (II)
Author(s) -
Kanamaru Hiroshi,
Kamada Takeshi,
Nakatsuka Iwao,
Mohri ZenIchi,
Okamura Taeko,
Yoshitake Akira
Publication year - 1981
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2580180905
Subject(s) - chemistry , fenvalerate , potassium cyanide , bromide , yield (engineering) , cyanide , medicinal chemistry , acetonitrile , sodium methoxide , organic chemistry , methanol , pesticide , materials science , agronomy , metallurgy , biology
(S)‐α‐Cyano‐3‐phenoxybenzyl (S)‐2‐(4‐chlorophenyl)‐3‐methylbutyrate (fenvalerate Aα), an optically active insecticide, was labelled with carbon‐14 individually at the benzyl ring ( 1a ) and the chlorophenyl ring ( 1b ) for use in metabolic studies. Ullmann reaction of 3‐methylphenol‐ 14 C 6 ( 2 ) with bromobenzene followed by oxygen oxidation gave 3‐phenoxybenzoic‐ 14 C 6 acid ( 4 ). Reduction of 4 followed by potassium dichromate oxidation of the alcohol ( 5 ) gave 3‐phenoxybenzaldehyde‐ 14 C 6 ( 6 ). Condensation of 6 with (S)‐2‐(4‐chlorophenyl)‐3‐methylbutanoyl chloride and sodium cyanide afforded fenvalerate A‐(benzyl‐ 14 C 6 ), which on optical resolution gave 1a in 29% yield from 2 . Isopropylation of 4‐chlorophenyl‐ 14 C 6 ‐acetonitrile ( 9 ) followed by hydrolysis gave 2‐(4‐chlorophenyl‐ 14 C 6 )‐3‐methylbutyric acid which on optical resolution gave the (S)‐acid ( 12 ). Esterification of the acid with α‐cyano‐3‐phenoxybenzyl bromide yielded fenvalerate A‐(phenyl‐ 14 C 6 ), which was resolved to give 1b in 9% yield from 9 .