Cyclopropanemethanamine → N-cyclopropylmethyl-4-methyl-3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-benzamide

Participants

Reaction Steps

4-Methyl-3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-benzoic acid (Intermediate 17) (2.0 g, 7.63 mmol), DIPEA (4 ml, 22.89 mmol) and HATU (3.05 g, 8.02 mmol) were dissolved in DMF (20 ml) and stirred at room temperature for 15 mins. Cyclopropylmethylamine (568 mg, 8.01 mmol) was added and the reaction stirred at room temperature for 18 hours. The solvent was evaporated under vacuum and the reaction partitioned between ethyl acetate (250 ml) and water (50 ml). The organic phase was washed with hydrochloric acid (2N, 50 ml) and aqueous sodium bicarbonate (1M, 50 ml), then dried (magnesium sulphate) and the solvent evaporated under vacuum. The residue was absorbed onto silica and purified by flash column chromatography eluting with cyclohexane/ethyl acetate (4:1). The solvent was evaporated from the product fractions under vacuum to give N-cyclopropylmethyl-4-methyl-3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-benzamide (1.73 g). LCMS: retention time 3.47 min, MH− 316. NMR: δH [2H6]-DMSO 8.54, (1H, t), 8.11, (1H, d), 7.82, (1H, dd), 7.26, (1H, d), 3.12, (2H, t), 1.32, (12H, s), 1.03, (1H, m), 0.42, (2H, m), 0.22, (2H, m).

Provenance & Evidence