Sodium hydride → 4-(4,4-Dimethoxybutyl)-5-oxo-[1,4]diazepane-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

To a suspension of 60% sodium hydride in mineral oil (0.2 g, 5 mmole) in N,N-dimethylformamide (6 mL) was added 5-oxo-[1,4]diazepane-1-carboxylic acid tert-butyl ester (1.0 g, 4.67 mmole). The reaction mixture was warmed at 50° C. for 5 minutes, and then at room temperature for 15 minutes. To the resulting solution was added 4-bromobutyraldehyde dimethyl acetal (0.99 g, 5 mmole). After the reaction mixture was stirred at room temperature for 16 hours, the solvent was removed, and the residue was partitioned between water and ethyl acetate. The organic phase was washed with water, dried (magnesium sulfate), and concentrated. The residue was dissolved in diethyl ether, and the suspension was filtered, and the filtrate was concentrated. Purification by silica gel chromatography, eluting with 2% methanol in chloroform, gave 4-(4,4-dimethoxybutyl)-5-oxo-[1,4]diazepane-1-carboxylic acid tert-butyl ester (0.8 g,) as a heavy syrup. Nmr: (chloroform-d) δ (ppm) 1.49, s, (9H); 2.64, m, 3H; 3.32, s (3H); 4.37, m, (1H).

Provenance & Evidence