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Reaction of sulfenes with heterocyclic N,N ‐disubstituted α‐aminomethyleneketones. XIII. Synthesis of 1,2‐oxathiino[6,5‐ f ]quinazoline derivatives
Author(s) -
Menozzi Giulia,
Bargagna Alberto,
Mosti Luisa,
Sche Pietro
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.5570240317
Subject(s) - chemistry , quinazoline , cycloaddition , dehydrogenation , medicinal chemistry , benzene , boiling , organic chemistry , catalysis
The 1,4‐cycloaddition of sulfene to N,N ‐disubstituted ( E )‐6‐aminomethylene‐7,8‐dihydro‐(2‐methyl)‐(2‐phenyl)quinazolin‐5(6 H )‐ones I gave N,N ‐disubstituted 4‐amino‐3,4,5,6‐tetrahydro‐(8‐methyl) (8‐phenyl)‐1,2‐oxathiino[6,5‐ f ]quinazoline 2,2‐dioxides II , which are derivatives of the new heterocyclic system 1,2‐oxathiino[6,5‐ f ]quinazoline. With 2‐phenylenaminones Id‐h , the cycloaddition occurred, generally in satisfactory yields, both in the case of aliphatic N,N ‐disubstitution and aromatic N ‐monosubstitution, whereas with 2‐methyl enaminones Ia‐c the reaction took place in low yields only in the case of aliphatic N,N ‐disubstitution. Also the reaction of 2‐phenyl enaminones Id‐g with chlorosulfene occurred as with sulfene, giving a mixture of cycloadducts which were dehydrochlorinated in situ with DBN to afford N,N ‐di‐substituted 4‐amino‐5,6‐dihydro‐8‐phenyl‐1,2‐oxathiino[6,5‐ f ]quinazoline 2,2‐dioxides III generally in satisfactory yields. Compounds III could not be dehydrogenated either by DDQ in boiling benzene or by palladium on carbon in boiling p ‐cymene.