Cesium carbonate → 3-{3-[2-[Tert-butoxycarbonylimino]-3-(3-{4-[2-(4-chloro-phenyl)-5,5-dimethyl-cyclohex-1-enylmethyl]-piperazin-1-yl}-benzyl)-2,3-dihydro-benzoimidazol-1-yl]-propoxy)-benzoic acid

Participants

Reaction Conditions

Reaction Steps

To a degassed solution of 3-(3-{3-(3-bromo-benzyl)-2-[tert-butoxycarbonylimino]-2,3-dihydro-benzoimidazol-1-yl}-propoxy)-benzoic acid (0.15 g, 0.25 mmol) in toluene (2 ml) at rt under nitrogen was added Pd(OAc)2 (5 mg, 0.12 mmol) and BINAP (30 mg, 0.048 mmol). Nitrogen was bubbled through the mixture for 10 min before a degassed solution of 1-[2-(4-chloro-phenyl)-5,5-dimethyl-cyclohex-1-enylmethyl]-piperazine (90 mg, 0.28 mmol) in toluene (1 ml) was introduced. After 5 min Cs2CO3 (0.84 g, 2.58 mmol) was added. During all additions nitrogen was continuously bubbled through the reaction. Once the additions were completed the reaction vessel was sealed and then heated to 95° C. where it was maintained for 3 h. After this time, the reaction was cooled to rt and additional Pd(OAc)2 (5 mg, 0.12 mmol) and BINAP (30 mg, 0.048 mmol) were introduced. The reaction was then heated to 95° C. where it was maintained for a further 2 h. After this time, the reaction was cooled to rt and filtered through Celite®. The collected solids were washed with dichloromethane and the combined filtrate and washings were concentrated under reduced pressure. The crude product 3-{3-[2-[tert-butoxycarbonylimino]-3-(3-{4-[2-(4-chloro-phenyl)-5,5-dimethyl-cyclohex-1-enylmethyl]-piperazin-1-yl}-benzyl)-2,3-dihydro-benzoimidazol-1-yl]-propoxy}-benzoic acid (290 mg) was used in the next step without further purification. HPLC-MS 818, 820 [M+1]+.

Provenance & Evidence