Benzaldehyde → 1-[5-(Benzylidene-amino)-6-chloro-1-(2-methoxy-ethoxymethyl)-1H-benzoimidazol-2-yl]-1H-pyrazole-4-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

Benzaldehyde (93.0 mg, 0.876 mmol), 1-[5-amino-6-chloro-1-(2-methoxy-ethoxymethyl)-1H-benzoimidazol-2-yl]-1H-pyrazole-4-carboxylic acid ethyl ester (Intermediate from Example 41, product from Step A) (0.300 g, 0.762 mmol), THF (3 mL), and 4 Å molecular sieves (0.910 g) were combined and stirred for 18 h at 23° C. Sodium triacetoxyborohydride (0.242 g, 1.14 mmol) was added and stirring was continued for 4 days. The reaction was quenched with saturated aqueous sodium bicarbonate (15 mL) and stirred with dichloromethane (25 mL). This mixture was filtered and the layers were separated. The aqueous layer was extracted with dichlormethane (2×25 mL) and the combined organic layers were washed with brine (20 mL), dried, filtered, and concentrated under reduced pressure. The residue was purified (FCC) (10-45% EtOAc/hexanes) to yield the titled compound (0.288 g, 78% yield) as a 4:3 mixture of regioisomers. The titled compound was not stable enough to obtain a mass spectrum. 1H NMR (400 MHz, CDCl3): 8.87 (s, 1H), 8.48 (s, 1H), 8.19 (s, 1H), 8.03-7.94 (m, 2H), 7.73 (s, 1H), 7.58-7.48 (m, 3H), 7.39 (s, 1H), 6.12 (s, 2H), 4.36 (q, J=7.1 Hz, 2H), 3.7-3.6 (m, 2H), 3.5-3.4 (m, 2H), 3.32 (s, 3H), 1.39 (t, J=7.1 Hz, 3H).

Provenance & Evidence