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Condensed Pyridazines. Part I. Synthesis of 2‐Oxo‐2 H ‐pyrano[2,3‐ D ]‐pyridazine and 2‐Oxo‐2 H ‐pyrano[2,3‐ c ] pyridazine
Author(s) -
Maeba Isamu,
Ando Masahiko,
Yoshina Shigetaka,
Castle Raymond N.
Publication year - 1979
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.5570160210
Subject(s) - pyridazine , chemistry , ring (chemistry) , potassium cyanide , medicinal chemistry , stereochemistry , cyanide , organic chemistry
The reaction of 4,7‐diehlorofuro[2,3‐ d ]pyridazine (1) with potassium cyanide in DMSO gave two products, ( E )‐3,6‐diehloro‐5‐(2‐cyanovinyl)‐4‐hydroxypyridazine (II) and 5,8‐dichloro‐2‐oxo‐2 H ‐pyrano[2,3‐ d ]pyridazine (III) as a result of ring opening or ring expansion. A new ring system, 2‐oxo‐2 H ‐pyrano[2,3‐ c ]pyridazines (IX, XII, XIII) was obtained from 5,8‐dichloro‐3‐methyl‐2‐oxo‐2 H ‐pyrano[2,3‐ d ]pyridazine (VI).