tert-butyl N-[2-(pyridin-2-ylamino)ethyl]carbamate → 5-[2-(Pyridin-2-ylamino)-ethylcarbamoyl]-thiophene-2-carboxylic acid methyl ester

Participants

Reaction Steps

To a solution of [2-(Pyridin-2-ylamino)-ethyl]-carbamic acid tert-butyl ester (44 mg, 0.14 mmol) was mixed with a mixture of (1:1)TFA/CH2Cl2 (30 mL) and the reaction mixture was stirred at room temperature overnight. The solvent was evaporated and the residue was tritured with dry ether (2×30 mL). This gave 35 mg (95%) of pure trifluoroacetate salt. The salt was neutralized with DIEA and treated with mono methylthiophene dicarboxylic acid (32 mg, 0.17 mmol), hydroxybenzotriazole (24 mg, 0.17 mmol) in DMF (20 mL). To this mixture was added 1-(3-dimethylamino) propyl)-3-ethylcarbodiimide hydrochloride (33 mg, 0.17 mmol). The reaction was stirred overnight at room temperature. Insolubles were removed by filtration and the solvent was evaporated. Purification of the residue on silica gel (5% MeOH/EtOAc) gave 38 mg (88%) of pure 5-[2-(Pyridin-2-ylamino)-ethylcarbamoyl]-thiophene-2-carboxylic acid methyl ester. 1HNMR (300 MHz, CDCl3) δ: 3.43 (m, 2H), 3.51 (m, 2H), 3.92 (s, 3H), 6.45(d, 1H) 6.80(t, 1H), 7.42(t, 1H), 7.45 (s, 1H), 7.55 (s, 1H), 8.10 (s, 1H).

Provenance & Evidence