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A convenient synthesis of 1,2‐diazepino[3,4‐ b ]‐quinoxalines via a 1,3‐dipolar cycloaddition reaction and their tautomeric structure in a solution
Author(s) -
Kim Ho Sik,
Kurasawa Yoshihisa,
Yoshii Chiemi,
Masuyama Minako,
Takada Atsushi,
Okamoto Yoshihisa
Publication year - 1990
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.5570270760
Subject(s) - chemistry , tautomer , quinoxaline , cycloaddition , 1,3 dipolar cycloaddition , stereochemistry , organic chemistry , catalysis
The reaction of the quinoxaline 4‐oxides 7a,b with 2‐chloroacrylonitrile resulted in the 1,3‐dipolar cycloaddition reaction and further alteration to give the 4‐hydroxy‐2,3‐dihydro‐1 H ‐1,2‐diazepino[3,4‐ b ]quinoxalines 8a,b and 9a,b , respectively, which were converted into the 4‐oxo‐2,3,4,6‐tetrahydro‐1 H ‐1,2‐diazepino[3,4‐ b ]‐quinoxalines 10a,b‐12a,b , respectively. The 2,3‐dihydro‐4‐hydroxy form of 9a,b and the 2,3,4,6‐tetrahydro‐4‐oxo form of 10a,b‐12a,b were assigned by means of the NOE and 13 C‐nmr spectral data.