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Structure and synthesis of the metribuzin blue dye. Synthesis and reactions of 2,5‐dihydrazino‐1,3,4‐thiadiazole and its derivatives
Author(s) -
Jackman Dennis Earl
Publication year - 1990
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570270445
Subject(s) - chemistry , derivative (finance) , metribuzin , formazan , oxidative decarboxylation , decarboxylation , organic chemistry , pigment , impurity , combinatorial chemistry , catalysis , biochemistry , weed control , financial economics , agronomy , economics , biology
A blue pigment which sometimes accompanies the manufacture of the triazine herbicide metribuzin ( 5 ) was identified as the novel thiadiazole formazan 10 which arises from the reaction of two impurities 3 and 7 . The latter compound is a keto acid derivative of 2,4‐dihydrazinothiadiazole which in turn is an impurity in carbonothioic dihydrazide. Compound 7 has the interesting property of undergoing a facile oxidative decarboxylation in the presence of alcohols to form hydrazonate esters and in the presence of aliphatic amines to form red amidrazone dyes 9 . The N ‐substituted dyes can be oxidized to ditriazolothiadiazoles 12 .