Tert-Butylamine → Tert.butyl 2-benzyloxycarbonyl-1,2,3,4-tetrahydropyrido[3,4-b]indole-1-carboxamide

Participants

Reaction Steps

A solution of 4.54 g of 2-benzyloxycarbonyl-1,2,3,4-tetrahydropyrido[3,4-b]indole-1-carboxylic acid in 45 ml of anhydrous tetrahydrofuran was cooled, while protecting with a drying tube, in an ice/acetone bath. 1.82 ml of N-ethylmorpholine and 1.82 ml of isobutyl chloroformate were added, the mixture was stirred for 10 minutes and then 2.1 ml of tert.butylamine were added. The mixture was then stirred at 0° C. for 40 minutes and at room temperature for 45 minutes, diluted with ethyl acetate and washed twice with water, twice with 0.5M sodium hydroxide solution and again with water. The solution was dried over magnesium sulphate and evaporated to dryness. Recrystallization from ethyl acetate and n-hexane gave 1.21 g of tert.butyl 2-benzyloxycarbonyl-1,2,3,4-tetrahydropyrido-[3,4-b]indole-1-carboxamide; MS: m/e 406 [M+H]+. A further 0.76 g of identical material was obtained by subjecting the mother liquors to chromatography on silica gel using ethyl acetate/n-hexane (1:1) for the elution.

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