Methylamine → N-methyl-4-(1,4-dihydroindeno[1,2-c]pyrazol-3-yl)benzamide

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Reaction Steps

A mixture of 4-(1,4-dihydroindeno[1,2-c]pyrazol-3-yl)benzoic acid (0.8 g), methylamine in ethanol (0.27 ml of a 33% w/w solution), 4-pyrrolidinopyridine (0.47 g), diisopropylcarbodiimide (0.5 ml) and dichloromethane (30 ml) was stirred at ambient temperature for 20 hours. More methylamine in ethanol (0.3 ml of a 33% w/w solution), 4-pyrrolidinopyridine (0.5 g) and diisopropylcarbodiimide (1 ml) were added and the mixture was stirred for 3 hours at ambient temperature. The solvent was removed under reduced pressure at 50° C. The mixture was kept under vacuum for 2 hours and then dichloromethane (50 ml) was added. The mixture was stirred at ambient temperature for 20 hours and then allowed to stand for 72 hours. A solid was removed by filtration and purified by flash column chromatography on silica using toluene/acetic acid (10:1) and then ethyl acetate as the mobile phase to give N-methyl-4-(1,4-dihydroindeno[1,2-c]pyrazol-3-yl)benzamide, m.p. 182-188° C.

Provenance & Evidence