Triethylamine → 1,1-Dimethylethyl 4-[4-[[methyl[(1R)-1-phenylpropyl]amino]carbonyl]-2-thiazolyl]-1-piperidinecarboxylate

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Reaction Steps

1-(1,1-Dimethylethyl) 4-(4-carboxy-2-thiazolyl)-1-piperidinecarboxylate (i.e. the product of Example 1, Step B) (3.1 g, 9.9 mmol) was suspended in 10 mL of dry acetonitrile and treated with triethylamine (3.0 mL, 21 mmol) to give a homogeneous solution. To this was added O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium hexafluorophosphate (3.98 g, 10.5 mmol) followed by (α,R)-α-ethyl-N-methylbenzenemethanamine (i.e. the product of Example 1, Step C) (10 mmol, 1.50 g). The mixture was stirred at ambient temperature for 4 days, concentrated under reduced pressure, diluted with ethyl acetate, washed with 1 N aqueous hydrochloric acid, saturated aqueous sodium bicarbonate solution and brine, dried over MgSO4 and concentrated under reduced pressure to give 5.1 g of a dark oil. Purification by silica gel chromatography using 25% ethyl acetate in hexanes gave 3.6 g of the title compound as a yellow oil.

Provenance & Evidence