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A Facile and Chemoselective Synthesis of Novel Pyrimido[5,4‐ b ][1,4]thiazines by exo ‐dig Iodocyclization Reactions
Author(s) -
Sharma Rashmi,
Mohan Chander
Publication year - 2017
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.2773
Subject(s) - chemistry , ketene , sulfanyl , dig , ring (chemistry) , cycloaddition , yield (engineering) , bicyclic molecule , pyrimidinones , closure (psychology) , combinatorial chemistry , stereochemistry , medicinal chemistry , organic chemistry , catalysis , computer science , law , materials science , computer security , political science , metallurgy
The present manuscript involves the synthesis of 5‐prop‐2‐ynylsulfanyl‐pyrimidin‐4‐ones 3a–i by [4 + 2] cycloaddition reactions of 1,3‐diazabuta‐1,3‐dienes 1a–i with prop‐2‐ynyl‐sulfanyl ketene 2 . These 5‐prop‐2‐ynylsulfanyl‐pyrimidin‐4‐ones 3a–i were explored in iodocyclization for the synthesis of novel pyrimido[5,4‐ b ][1,4]thiazines 4a–i in excellent yields. The iodocyclizations followed exo‐ dig ring‐closure cyclizations to yield 6–6 bicyclic fused pyrimidinones, while corresponding endo ‐dig ring‐closure iodoamination was not observed.