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Synthesis of pyrazolo[4′,3′:5,6]pyrazino[2,3‐c]pyrazoles and pyrazolo[4′,3′:5,6]pyrazino[2,3‐d]pyrimidines and their application to polyester fibres
Author(s) -
Rangnekar Dinesh W.
Publication year - 1990
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.280490403
Subject(s) - acetic anhydride , malononitrile , thiourea , chemistry , phenylhydrazine , formamide , polyester , hydrate , yield (engineering) , pyrimidine , hydrazine (antidepressant) , medicinal chemistry , organic chemistry , nuclear chemistry , stereochemistry , materials science , chromatography , catalysis , metallurgy
4‐Nitroso‐1‐phenyl‐3‐methyl‐5‐aminopyrazole ( 1 ) was condensed with ethylcyanoacetate ( 2 ), malononitrile ( 4a ) and 2‐cyanomethylbenzimidazole ( 4b ) to yield 6‐hydroxy‐5‐cyano, 6‐amino‐5‐cyano and 6‐amino‐5‐(benzimidazol‐2‐yl)‐3‐methylpyrazolo [3,4‐b]pyrazines 3, 5a and 5b , respectively. 5‐Cyano‐6‐chloro derivative 6 obtained from 3 was converted to 3‐aminopyrazolo[4′,3′:5,6]pyrazino[2,3‐c]pyrazoles 8a and 8b by the treatment with hydrazin hydrate ( 7a ) and phenylhydrazine ( 7b ), respectively. Compound 5a was treated with formamide ( 9a ), urea ( 9b ) and thiourea ( 9c ) to give 4‐aminopyrazolo[4′,3′:5,6]pyrazino[2′3′‐d]pyrimidines 10a–10c. With refluxing acetic anhydride compounds 8a, 8b and 10a gave corresponding acetamido derivatives 8c, 8d and 10d. Compound 5a was treated with ethylorthoformate ( 11 ), acetic anhydride ( 12 ) or benzoylchloride ( 13 ) to give fused benzimidazopyrazolo[4′,3′:5,6]pyrazino[2′,3′‐d]pyrimidines, viz., benzimidazol[1,2‐c]pyrazolo[4,3‐g]pteridines ( 14a–14c ). Some of the compounds 8, 10 and 14 were applied to polyester as disperse dyes and their fastness properties were studied.