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An improved procedure for the preparation of 1‐benzyl‐1 H ‐1,2,3‐triazoles from benzyl azides
Author(s) -
Cottrell Ian F.,
Hands David,
Houghton Peter G.,
Humphrey Guy R.,
Wright Stanley H. B.
Publication year - 1991
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.5570280216
Subject(s) - chemistry , acetophenone , methylene , ethyl acetoacetate , organic chemistry , ketone , potassium carbonate , medicinal chemistry , acetone , diethyl malonate , yield (engineering) , acetonitrile , catalysis , materials science , metallurgy
A procedure for the preparation of substituted 1‐benzyl‐1 H ‐1,2,3‐triazoles from benzyl azides under very mild conditions is described. The method provides improved yields and extends the scope of the Dimroth Reaction to other types of active methylene compound to those previously used. Benzyl azides react with active methylene compounds in dimethyl sulphoxide catalysed by potassium carbonate at 35–40° to give 1 H ‐1,2,3‐triazoles usually in good yield. Acetonitrile derivatives gave 5‐amino‐1 H ‐1,2,3‐triazoles whereas diethyl malonate gave 5‐hydroxy‐1 H ‐1,2,3‐triazoles. 1 H ‐1,2,3‐Triazole‐4‐carboxylate esters and 1 H ‐1,2,3‐triazole‐4‐ketones were obtained from ethyl acetoacetate and β‐diketones respectively. Benzyl methyl ketone reacted to give a 5‐methyl‐4‐phenyl‐1 H ‐1,2,3‐triazole, but acetone and acetophenone failed to react. Other active methylene compounds which did not react under these reaction conditions included ethyl cyanoacetate, ethyl fluoroacetate and ethyl nitroacetate.