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Studies with enamines: Reactivity of N,N ‐dimethyl‐ N ‐[( E )‐2‐(4‐nitrophenyl)‐1‐ethenyl]amine towards nitrilimine and aromatic diazonium salts
Author(s) -
AlMatar Hamad M.,
Riyadh Sayed M.,
Elnagdi Mohamed H.
Publication year - 2007
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.5570440315
Subject(s) - chemistry , triethylamine , enamine , medicinal chemistry , dimethylamine , oxime , acetic acid , hydrazone , acetophenone , organic chemistry , hydrochloride , amine gas treating , pyrazole , catalysis
In the presence of triethylamine, cycloaddition reaction of enamine 1 with hydrazonoyl halides 2 followed by dimethylamine elimination was achieved, yielding the corresponding 1,3,4‐trisubstituted pyrazoles 4 . Coupling of enamine 1 with aromatic diazonium salts afforded 2‐(arylhydrazono)‐2‐(4‐nitrophenyl)acetaldehyde 9 in good yield. Refluxing the phenyl hydrazone 9a with chloroacetone in ethanol in the presence of triethylamine afforded 1,3,5‐trisubstituted pyrazole 12a , formed via intermediate 11a. Reaction of 9a with hydroxylamine hydrochloride in ethanol in the presence of anhydrous sodium acetate yielded oxime 13a which was irradiated in a microwave oven in the presence of acetic acid to afford a mixture of 15a and 16a.