Studies on the reaction of 2-aminoacetophenone with thiophosgene |
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Authors: | Olaf Morgenstern Peter Richter Juha Rouvinen Pentti J Mlknen Pirjo Vainiotalo Kari Hnninen Markku Ahlgrn Jouko Vepslinen |
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Institution: | Olaf Morgenstern,Peter Richter,Juha Rouvinen,Pentti J. Mälkönen,Pirjo Vainiotalo,Kari Hänninen,Markku Ahlgrén,Jouko Vepsäläinen |
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Abstract: | 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. |
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