Triethylamine → HCID 67145028, compound

Participants

Reaction Steps

A catalytic amount of DMF (2 drops) was added to a solution of 4-(5-bromopentyloxy)-5-methoxy-2-nitro-benzoic acid 17 (270 mg, 0.74 mmol) and oxalyl chloride (80 μL, 0.89 mmol) in anhydrous THF (7.5 mL) and the resulting mixture was stirred at rt for an overnight. Excess THF and oxalyl chloride were removed with rotavapor. The acetyl chloride was resuspended in fresh THF (6 mL) and was added dropwise to a solution of 4-methylene-L-proline methyl ester 5 (228 mg, 0.89 mmol), Et3N (0.32 mL, 2.31 mmol), and H2O (0.15 mL) in THF (1.5 mL) at 0° C. under argon atmosphere. The reaction mixture was allowed to warm to rt and stirring was continued for 4 h. After removal of THF, the residue was partitioned between H2O and EtOAc (20/20 mL). The aqueous layer was further extracted with EtOAc (3×10 mL). The combined organic layers were washed with brine (20 mL), dried (MgSO4) and concentrated. Purification of the residue by flash chromatography (silica gel, 6:4 hexanes/EtOAc) yielded 1-[4-(5-bromopentyloxy)-5-methoxy-2-nitro-benzoyl]-4-methylene-L-proline methyl ester 18 as light yellow oil (rotamers): 1HNMR (300 MHz, CDCl3, rotamers) δ 1.62-1.68 (m, 2H), 1.86-1.98 (m, 4H), 2.64-2.75 (m, 1H), 2.99-3.08 (m, 1H), 3.43 (t, J=5.1 Hz, 2H), 3.59-3.96 (m, 7H), 4.05-4.21 (m, 3H), 4.57-4.61 and 4.90-5.12 (m, 3H), 6.80 and 6.83 (2 s, 1H), 7.64 and 7.67 (2 s, 1H); EIMS m/z 507 and 509 ([M]++Na).

Provenance & Evidence