Diisopropylethylamine → HCID 131724035, compound

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Reaction Steps

A solution of [3-methoxy-4-(3-o-tolyl-ureido)-phenyl]-acetic acid (2.9 g) and O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (3.7 g) in dimethylformamide (about 40 ml) was treated with diisopropylethylamine (10 ml), followed after about 30 seconds by a solution of (R/S) ethyl 3-(2,3-dihydro-1H-indol-5-yl)butyrate [about 2.5 g, Reference Example 5(a)] in dimethylformamide (about 10 ml). The resulting clear, dark brown solution was kept at room temperature for about one hour then evaporated to low bulk. The residue was partitioned between water and ethyl acetate and the organic layer was washed with dilute hydrochloric acid, then with aqueous sodium bicarbonate solution, then with brine, then dried and then evaporated. The residual brown gum was subjected to flash chromatography on silica eluting with a mixture of ethyl acetate and petrol (3:2 to 3:1, v/v) to give the title compound (2.8 g) as a light yellow, amorphous foam. MS (ES+) 552 (M−Na+).

Provenance & Evidence