Allylamine → 6-Chloro-3,4-dihydro-N-2-propen-1-yl-2H-1-benzopyran-2-carboxamide

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Reaction Steps

A solution of 3.1 g of 6-chloro-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid (1A) (Witiak et al. (1971), supra) in 15 ml of thionyl chloride was refluxed for 45 minutes. The excess thionyl chloride then was stripped off and the residual liquid taken up in 50 ml of methylene chloride. To this stirred solution was added dropwise a solution of 2.5 g of 2-propenamine in 10 ml of methylene chloride. The resulting mixture was stirred at room temperature overnight, then was washed with water, dried (MgSO4) and stripped of solvent. Dry column chromatography of the solid product through silica gel, using Solvent No. 3 (a 4:30:66 by volume mixture of tetrahydrofuran, ethyl acetate and hexane) as eluent, followed by recrystallization of the product from ethylene chloride and hexane gave 1, as a pale yellow solid, mp: 112.5°-114° C. Example 2

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