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The reaction of isothiocyanates with 2‐cyanoethanoic acid hydrazide. A novel synthesis of 1,3,4‐thiadiazoles
Author(s) -
Elmoghayar Mohamed Rifaat Hamza,
Abdalla Sanaa Osman,
Nasr Mohamed Yousry AbdelSamad
Publication year - 1984
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.5570210329
Subject(s) - chemistry , hydrazide , thiadiazoles , potassium hydroxide , yield (engineering) , acetic acid , medicinal chemistry , derivative (finance) , diazomethane , organic chemistry , triazine , ethyl acetoacetate , malononitrile , catalysis , materials science , economics , financial economics , metallurgy
Benzoyl and ethoxycarbonyl isothiocyanates reacted with 2‐cyanoethanoic acid hydrazide 2 to afford 1‐cyanoacetyl‐4‐substituted thiosemicarbazide ( 5a,b ). Compound 5a afforded the pyrazolo[1,5‐ a ]‐ s ‐triazine derivative 6 on treatment with 5% potassium hydroxide, and cyclised to 2‐benzoylamino‐5‐cyanomethyl‐1,3,4‐thiadiazole ( 8 ) when boiled under reflux in glacial acetic acid. Compound 8 condensed with aromatic aldehydes to yield the corresponding arylidene derivatives 9a‐c . It undergoes coupling with aromatic diazonium salts to afford the hydrazones 11a‐c . Similarly, it coupled with diazotised aminopyrazole to afford the cyclic product 12 .