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A New and Convenient Synthesis of 1,2‐Diamino‐3‐hetarylpyrrole Derivatives
Author(s) -
Volovenko Yulian M.,
Tverdokhlebov Anton V.,
Gorulya Alexandr P.,
Shishkina Svetlana V.,
Zubatyuk Roman I.,
Shishkin Oleg V.
Publication year - 2002
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200202)2002:4<663::aid-ejoc663>3.0.co;2-a
Subject(s) - chemistry , steric effects , alkylation , nitrogen atom , reagent , triethylamine , medicinal chemistry , intramolecular force , ring (chemistry) , stereochemistry , organic chemistry , catalysis
A number of 1‐acylamino‐2‐amino‐3‐hetaryl‐4‐oxo‐2‐pyrrolines 13 − 50 were prepared by treatment of 4‐chloro‐2‐hetaryl‐3‐oxobutanenitriles 11a − h with substituted benzoic and 2‐furanoic acid hydrazides in DMF at 110−120 °C. When the same reagents were coupled in the presence of triethylamine, a definite dependence of the course of the reaction on the nature of the chloronitriles 11a − h was observed. The steric arrangement of the heterocyclic nitrogen atom in chloronitriles 11 seemed to have a critical influence on the nature of the products obtained. Thus, compounds 11d − h with sterically hindered nitrogen atoms gave the pyrrolines 25 − 50 mentioned above, while unhindered derivatives 11a − c afforded products of intramolecular alkylation, namely the 3‐cyano‐2‐oxo‐1,2‐dihydropyrrolo[1,2‐ a ]benzazoles 51 − 53 . An X‐ray diffraction study of 2‐amino‐3‐(2‐benzothiazolyl)‐1‐( p ‐nitrobenzoylamino)‐4‐oxo‐2‐pyrroline ( 24 ) was carried out to confirm the structures of compounds 13 − 50 unambiguously. An attempt to extend this reaction to p ‐tolylsulfonylhydrazine resulted in the simple alkylation products 12a , 12c , and 12e , without subsequent ring closure.