Maleic Anhydride → HCID 178498080, compound

Participants

Reaction Steps

To a suspension of L-proline methyl ester hydrochloride (200 mg, 1.21 mmole) in 8 mL of ethylene glycol dimethyl ether was added triethylamine (244 mg, 2.4 mmole). The white cloudy mixture was stirred at ambient temperature for 20 min, and was then treated with maleic anhydride in 1 mL of diethyl ether. After 1 hour, the reaction mixture was filtered. The filtrate was mixed with a solution of N-hydroxysuccinimide (172 mg, 1.5 mmole) in ethylene glycol dimethyl ether, and then DCC (412 mg, 2 mmole) was added. The reaction mixture was stirred at ambient temperature overnight. After filtration, the solution of the NHS ester was added in 4 mL portions to a solution of 5-(aminomethyl)-4-(3-fluorophenylhydrazono)-3-amino-4H-pyrazole (60 mg, 0.25 mmole) and triethylamine (0.51 mmole, 52 mg) in 4 mL of DMF at 45° C. After stirring at ambient temperature for 45 minutes, the reaction was quenched by the addition of saline and ethyl acetate. The ethyl acetate extracts were concentrated and the resulting crude material was purified by preparative TLC (CH2Cl2:CH3OH=12:1) to yield 44 mg (38%) of the title compound as a yellow powder. MS (m/z, ES+): 444 (M+1, 56%), 445 (M+2, 13%); 1H NMR (ppm, 300 MHz, DMSO-d6) δ 11.92 (br s, 1H), 8.80 (br s, 1H), 7.35-7.62 (m, 3H), 7.10 (d, J=14.8 Hz, 1H), 7.09 (br s, NH2), 6.90 (d, J=14.8 Hz, 1H), 4.56 (dd, J=8.5 Hz, 1H), 4.36 (dd, J=8.5, 4.0 Hz, 1H), 3.66 (m, 1H), 3.60 (s, OCH3), 3.45 (m, 1H), 3.34 (m, 1H), 2.17 (m, 1H), 1.75-2.00 (m, 3H).

Provenance & Evidence