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Iminium carbonic acid derivative salts. X . Synthesis of N,S ‐containing heterobicycles from N ‐protected 2‐methylthio‐1,3‐thiazinium and 2‐methylthiothiazolium salts. Part 2 . Reaction of N ‐protected 2‐methylthio‐1,3‐thiazinium and 2‐methylthiothiazolium salts with vinylogous CH‐acidic compounds
Author(s) -
Hanefeld Wolfgang,
Naeeni Mahmoud,
Schlitzer Martin
Publication year - 1996
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.5570330640
Subject(s) - chemistry , iminium , tetrafluoroborate , trifluoroacetic acid , methyl iodide , medicinal chemistry , derivative (finance) , thiazolidine , salt (chemistry) , iodide , ketene , stereochemistry , organic chemistry , ion , ionic liquid , financial economics , economics , catalysis
Abstract N ‐Boc‐protected 2‐methylthio‐1,3‐thiazinium 3 and 2‐methylthiothiazolium salts 4,7 obtained from the corresponding 1,3‐thiazine‐2‐thiones and thiazolidine‐2‐thiones by the action of methyl iodide or trimethyloxonium tetrafluoroborate were reacted with vinylogous CH‐acidic compounds forming ketene N,S ‐acetals 5,6,8,9 . The protection group was removed with trifluoroacetic acid whereupon the desired cyclisation to pyrido[2,1‐ b ]‐1,3‐thiazines 10 and thiazolo[3,2‐ b ]pyridines 11,12 took place.