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Studies on the reaction of 2‐aminoacetophenone with thiophosgene
Author(s) -
Morgenstern Olaf,
Richter Peter,
Rouvinen Juha,
Mälkönen Pentti J.,
Vainiotalo Pirjo,
Hänninen Kari,
Ahlgrén Markku,
Vepsäläinen Jouko
Publication year - 1991
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.5570280443
Subject(s) - chemistry , chloroform , methylene , monomer , reaction conditions , rearrangement reaction , organic chemistry , catalysis , polymer
The reaction of 3‐ and 4‐aminoacetophenone with thiophosgene in a chloroform‐water‐calcium carbonate mixture at room temperature results in good yields of the related, known isothiocyanates. At first, however, we failed in all our attempts to produce 2‐isothiocyanatoacetophenones with this reaction. Closer inspection of the reaction showed, that the product distribution depends upon the concentration of hydrogen ions pro‐ducted and on the reaction time. When the reaction was followed with thin‐layer chromatography, it was observed that the isothiocyanates formed first. In the further course of the reaction, they were converted to the 4‐methylene‐2‐oxo‐3,1‐benzothiazines by the action of protons. The final products of the reaction were the 4‐(3,1‐benzothiazin‐4‐yl)‐methylene‐3,1‐benzothiazines, formed from the monomer in a dimerization process. Depending upon the time the protons were removed from the reaction mixture, different products could be isolated.