Triphenylphosphine → Diethyl1-(2-((tert-butoxycarbonyl)amino)-2-cyclopropylethyl)-3-iodo-1H-pyrazole-4,5-dicarboxylate

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of PPh3 (15.52 g, 59.2 mmol) in THF (40.0 mL) cooled to −10° C. was added DIAD (11.50 mL, 59.2 mmol) and the resulting solution stirred at 0° C. for 0.5 h. Intermediate 104C (10 g, 29.6 mmol) was added as a solution in THF (10 mL) at 0° C. and stirred at RT for 45 min. A solution of Intermediate 348A (7.74 g, 38.5 mmol) in THF (10 mL) at was added at 0° C. and the reaction mixture was allowed to stir at RT for 16 h. The reaction mixture was diluted with EtOAc (50 mL) washed with water and brine. The organic layer was dried over Na2SO4 and concentrated under reduced pressure. The crude compound was purified by silica gel chromatography (120 g REDISEP® column, eluting with 15% EtOAc in hexanes). Fractions containing the product were combined and evaporated to afford Intermediate 348B along with impurities arising from the coupling reagents (8.01 g, 84%); the crude material was taken to the next step without further purification. MS(ES): m/z=522 [M+H]+.

Provenance & Evidence