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Reaction of sulfene and dichloroketene with open‐chain N,N ‐disubstituted α‐aminomethyleneketones. Synthesis of 4‐dialkylamino‐3,4‐dihydro‐6‐methyl‐5‐phenyl‐1,2‐oxathiin 2,2‐dioxides and of N,N ‐disubstituted 4‐amino‐3‐chloro‐(6‐methyl‐5‐phenyl)(6‐benzyl)‐2 H ‐pyran‐2‐ones
Author(s) -
Bargagna Alberto,
Evangelisti Filippo,
Sche Pietro
Publication year - 1981
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.5570180123
Subject(s) - chemistry , cycloaddition , yield (engineering) , pyran , medicinal chemistry , stereochemistry , derivative (finance) , organic chemistry , catalysis , materials science , metallurgy , economics , financial economics
Cycloaddition of sulfene to N,N ‐disubstituted 4‐amino‐3‐phenyl‐3‐buten‐2‐ones (III) occurred in good yield only in the case of aliphatic N ‐substitution to give 4‐dialkylamino‐3,4‐dihydro‐6‐methyl‐5‐phenyl‐1,2‐oxathiin 2,2‐dioxides, whereas N,N ‐disubstituted 4‐amino‐1‐phenyl‐3‐buten‐2‐ones (IV) did not react at all. Polar 1,4‐cycloaddition of dichloroketene to III and IV occurred partly in the case of aromatic N ‐substitution, with the exception of the morpholino derivative IVd, giving in low yield N,N ‐disubstituted 4‐amino‐3,3‐dichloro‐3,4‐dihydro‐(6‐methyl‐5‐phenyl)(6‐benzyl)‐2 H ‐pyran‐2‐ones, which were dehydrochlorinated with DBN to the corresponding 4‐amino‐3‐chloro‐(6‐methyl‐5‐phenyl)(6‐benzyl)‐2 H ‐pyran‐2‐ones (VII) in good yield. In some cases of aliphatic N,N ‐disubstitution of III and IV, cycloaddition led directly to N,N ‐dialkyl derivatives VII in low yield.