O-(Benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate → (S)-4-[2-(3-Fluoro-2-methyl-benzyl)-1-phenyl-indolizine-3-carbonyl]-2-{[(tetrahydropyran-4-ylmethyl)-carbamoyl]-methyl}-piperazine-1-carboxylic acid tert-butyl ester

Participants

Reaction Steps

To a stirred, ice-cold solution of 4-aminomethyl-tetrahydropyran (0.047 g, 0.40 mmol), EDIA (0.19 ml, 1.08 mmol) and the compound of step 2 (0.190 g, 0.27 mmol) was added TBTU (0.259 g, 0.81 mmol) in small portions. The solution was stirred at room temperature for 18 h. Then water (8 ml) was added and the mixture was extracted 3 times with EA. The combined organic phases were washed with 1 N hydrochloric acid, water, a saturated solution of sodium hydrogencarbonate and brine, dried over sodium sulfate, filtered and evaporated to dryness under reduced pressure. The residue was purified by chromatography on silica gel (cyclohexane/EA, 100:0, then 50:50) to give 0.117 g of the title compound as an orange gum.

Provenance & Evidence