Synthesis of 3‐Alkoxybenzo[c]thiophen‐1(3H)‐ones by Hydrolysis of N‐Substituted 3‐Alkoxybenzo[c]thiophen‐1(3H)‐imines Derived from 1‐Bromo‐2‐(dialkoxymethyl)benzenes and Isothiocyanates |
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| Authors: | Kazuhiro Kobayashi Minami Kuroda Yuuki Kanbe |
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| Institution: | Division of Applied Chemistry, Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4‐101 Koyama‐minami, Tottori 680‐8552, Japan, (phone/fax: +81‐857‐315263) |
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| Abstract: | A convenient procedure for the preparation of a new type of thiophthalides, 3‐alkoxybenzoc]thiophen‐1(3H)‐ones 4 and 9 has been developed. Thus, 1‐(dialkoxymethyl)‐2‐lithiobenzenes, generated by Br/Li exchange between 2‐bromo‐1‐(dialkoxymethyl)benzenes 1 and 6 , and BuLi, react with isothiocyanates to afford N‐substituted 2‐(dialkoxymethyl)benzothioamides 2 and 7 , which, on treatment with a catalytic amount of TsOH?H2O, give N‐substituted 3‐alkoxybenzoc]thiophen‐1(3H)‐imines 3 and 8 . The latter are hydrolyzed under acidic conditions to the desired products 4 and 9 , respectively. |
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| Keywords: | Benzo[c]thiophen‐1(3H)‐ones Thiophthalides Benzothioamides Benzenes (dialkoxymethyl)‐2‐lithio‐ |
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