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Cyanoacetic acid hydrazide: An efficient access for the synthesis of multi‐functional azine and azole derivatives
Author(s) -
ElSayed Hassan A.,
Abd Elazim Mohamed H. M.,
Assy M. G.,
Atef Islam
Publication year - 2020
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.3926
Subject(s) - chemistry , malononitrile , derivative (finance) , pyridazine , hydrazide , azine , pyrazole , cyanoacetic acid , isothiocyanate , thiourea , diazomethane , phenyl isothiocyanate , azole , organic chemistry , medicinal chemistry , combinatorial chemistry , catalysis , financial economics , economics , antifungal , medicine , dermatology
Abstract Herein, the synthesis of nitrogen‐containing heterocyclic scaffolds from heterocyclization of cyanoacetic acid hydrazide derivatives is described. Thiosemicarbazide derivative 1a undergoes base‐mediated cyclization producing pyrazole derivative of type 2 . The triazolopyridine 5 was obtained by double cyclization of 1a and benzylidene malononitrile. Compound 1b condensed with ethyl chloroformate to furnish pyrazolooxazine 8 . Compound 1b was added to benzoyl isothiocyanate under thermal condition to form oxadiazine derivative 10 while, keeping the above reactant under room temperature to form acyclic derivative 11 . Using CS 2 as a cyclizing agent for compound 1b yielded pyrazole derivative 13 . Treatment of 1b with I 2 resulted in oxidative cyclization producing pyridazine derivative 14 . Compound 1c cyclized with benzoyl isothiocyanate forming triazolothiazine derivative 18 . While using cinnamoyl isothiocyanate, the acyclic product 22 was obtained. Compound 1c was condensed with formaldehyde leading to oxadiazole derivative 25 .