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Access to the 2,3‐dihydropyridazin‐3‐one and as ‐triazino[3,4‐ a ]phthalazine ring systems from 4‐aryl‐2‐oxo‐butanoic acids
Author(s) -
ElAshry ElSayed H.,
Amer Adel,
Labib George H.,
Abdel Rahman Mohamed M.,
ElMassry Abdel Monem
Publication year - 1987
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.5570240114
Subject(s) - chemistry , phthalazine , acetic anhydride , aryl , medicinal chemistry , acetic acid , hydrochloric acid , condensation reaction , phenacyl , organic chemistry , mass spectrum , condensation , alkyl , catalysis , ion , physics , thermodynamics
A novel series of 2,3‐dihydropyridazin‐3‐ones 15 were synthesized via condensation between hydrazines and 4‐( p ‐chlorophenyl)‐2‐hydroxy‐2‐(2‐oxo‐2‐substituted ethyl)butanoic acids 8 which in turn were prepared by the reaction of substituted benzylpyruvic acids 6 with methyl alkyl(aryl) ketones 7. Dehydration of 8b‐d by a mixture of glacial acetic acid and hydrochloric acid afforded 4‐( p ‐chorophenyl)‐2‐(substituted phenacyl)‐2‐butenoic acids 10. Condensation reaction of 10 with hydrazines gave type 15 compounds in good yields. Also, a new series of as ‐triazino[3,4‐ a ]phthalazines 20 was obtained from the reaction of substituted benzylpyruvic acids 6 with hydralazine to give the hydralazones 19 which underwent dehydrative cyclization reaction with PPA to afford 20. Structure assignments are based on 1 H, 13 C nmr and ir spectra.