Premium
On triazoles. VIII The reaction of 5‐amino‐1,2,4‐triazoles with ethyl 2‐cyano‐3‐ethoxyacrylate and 2‐cyano‐3‐ethoxyacrylonitrile
Author(s) -
Reiter József,
Pongó László,
Dvortsák Péter
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.5570240443
Subject(s) - chemistry , pyrimidine , yield (engineering) , ring (chemistry) , stereochemistry , proton , reaction conditions , spectral line , molecule , medicinal chemistry , organic chemistry , catalysis , materials science , astronomy , metallurgy , physics , quantum mechanics
The reaction of different 5‐amino‐3‐Q‐1 H ‐1,2,4‐triazoles 1 with ethyl 2‐cyano‐3‐ethoxyacrylate ( 5a ) and 2‐cyano‐3‐ethoxyacrylonitrile ( 5b ) to yield either the a type 5‐amino‐, or the b type 7‐amino‐1,2,4‐triazolo[1,5‐ a ]‐pyrimidine derivatives 6–10 was studied. The structure of compounds 6 and 9 was proved by their degradation to the corresponding derivatives 17a and 18a , respectively, through intermediates 11a, 12a, 13a, 14a, 15a and 16a , respectively. The structure of derivatives 7, 8 and 10 was proved on the basis of the analogy of their uv spectra with those of 6a and 9a , respectively. The isolation of the intermediates 19 and 20 helped to prove the mechanism of the reactions leading to the formation of 6a and 9a , respectively. In the reaction of the N ‐substituted 5‐amino‐1,2,4‐triazoles with 5a the expected condensed ring products were not formed. Instead the aminoacrylates 22 and 24 were obtained. The “ Z ”‐“ E ” isomeric structure of derivatives 19, 20, 22 and 24 was proved with the help of their pmr spectra. The “ Z ” isomeric structure of the thermodynamically stabile 22 was corroborated with the help of its proton coupled cmr spectra, too.