The synthesis of 1H-benzimidazole derivatives containing a 9H-xanthene or 9H-thioxanthene ring |
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Authors: | Ichizo Okabayashi Hidetoshi Fujiwara |
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Affiliation: | Niigata College of Pharmacy, 5829 Kamishin'ei-cho, Niigata, 950–21, Japan |
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Abstract: | 2-(9H-Xanthen-9-ylmethyl)-1H-benzimidazole ( 2a ) was prepared by condensing 9H-xanthene-9-acetic acid ( 1a ) with 1,2-benzenediamine. Similarly, 2-(9H-thioxanthen-9-ylmethyl)-1H-benzimidazole ( 2b ) and its S,S-dioxide ( 2d ) were obtained. Compound 2d was also prepared by oxidizing 2b with hydrogen peroxide in acetic acid. Heating of 9H-thioxanthene-9-acetic acid 10-oxide ( 1c ) with 1,2-benzenediamine gave 9-methylene-9H-thioxanthene ( 3 ). 2-(9H-Thioxanthen-9-ylmethyl)-1H-benzimidazole S-oxide ( 2c ) was obtained by oxidizing 2b with m-chloroperbenzoic acid in acetone. |
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