Sodium hydride → 4-[3-(4-Formyl-3-methyl-phenoxy)-propyl]-5-oxo-[1,4]diazepane-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

4-{3-[4-(6-Chloro-4-methyl-1H-benzoimidazol-2-yl)-3-methyl-phenoxy]-propyl}-[1,4]diazepan-5-one. To a stirred solution of 5-oxo-[1,4]diazepane-1-carboxylic acid tert-butyl ester (3.0 g, 14.0 mmol, 1.0 equiv) in DMF (45 mL) at rt was added 60% sodium hydride (560 mg, 14.0 mmol, 1.0 equiv). After stirring for 30 min, 4-(3-iodo-propoxy)-2-methyl-benzaldehyde (4.26 g, 14.0 mmol, 1.0 equiv) was added as a solution in DMF (5 mL). The mixture was stirred for 16 h and then poured into water and extracted with ethyl acetate. The combined extracts were dried (Na2SO4), filtered, and concentrated. The residue was partially purified by column chromatography (silica gel, 5-50% ethyl acetate in hexanes) to afford 4-[3-(4-formyl-3-methyl-phenoxy)-propyl]-5-oxo-[1,4]diazepane-1-carboxylic acid tert-butyl ester as a mixture with several unidentified products. This impure mixture (200 mg), 5-chloro-3-methyl-benzene-1,2-diamine (80.1 mg), and Na2S2O5 (97 mg) were stirred in DMF (1.0 mL) at 90° C. for 3 h. After cooling to rt, the reaction mixture was loaded on silica gel and was purified by Method 2 to afford 4-{3-[4-(6-chloro-4-methyl-1H-benzoimidazol-2-yl)-3-methyl-phenoxy]-propyl}-5-oxo-[1,4]diazepane-1-carboxylic acid tert-butyl ester as a mixture with several unidentified products. This mixture was dissolved in dichloromethane (1.0 mL) and TFA (1.0 mL) and stirred at rt for 1 h. The reaction mixture was loaded on silica gel and purified by Method 2 to afford 91.0 mg (42%) of the title compound. MS (electrospray): mass calculated for C23H27ClN4O2, 426.18; m/z found, 427.4 [M+H]+. 1H NMR (400 MHz, CD3OD): 7.55 (d, J=8.5 Hz, 1H), 7.42 (br s, 1H), 7.09-7.06 (m, 1H), 6.97 (d, J=2.4 Hz, 1H), 6.93 (dd, J=8.5, 2.5 Hz, 1H), 4.10 (t, J=6.1 Hz, 2H), 3.67-3.56 (m, 4H), 2.98-2.89 (m, 4H), 2.72-2.66 (m, 2H), 2.59 (s, 3H), 2.50 (s, 3H), 2.12-2.01 (m, 2H).

Provenance & Evidence