• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.135-137
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• 1999

For the synthesis of new anti-inflammatory agents as indol derivatives, we have synthesized ${\alpha}$-benzoyl-1-ethyl-1,3,4,9-tetrahydro-8-ethyl-9-(N-benzoyl)pyrano[3,4-b]indole-1-acetic acid methyl ester. It was a new method for ${\alpha}$-substituted etodolac carboxylic acid. The synthetic process was composed of four steps, and 7-ethylindole and oxalyl chloride were used as starting materials. The third step, cyclization was carried out by addition of borontrifluoride diethyl etherate in 66% yield. The step of reduction and cyclization were simplified successfully. The final product, ${\alpha}$-benzoyl-1-ethyl-1,3,4,9-tetrahydro-8-ethyl-9-(N-benzoyl)pyrano[3,4-b]indole-1-acetic acid methyl ester was obtained in 66% yield by the reaction of methyl 1,8-dimethyl-1,3,4,9-tetrahydropyrano[3,4-b]indole-1-acetate (etodollic acid methyl ester) and benzoyl chloride.