Triphenylphosphine → 4-(9-Benzenesulfonyl-3-bromo-6-cyano-9H-dipyrido[2,3-b;4',3'-d]pyrrol-5-yloxy)piperidine-1-carboxylic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 9-benzenesulfonyl-3-bromo-5-hydroxy-9H-dipyrido[2,3-b;4′,3′-d]pyrrole-6-carbonitrile (15.8 g, 36.8 mmol), 4-hydroxypiperidine-1-carboxylic acid tert-butyl ester (18.5 g, 92.0 mmol) and triphenylphosphine (24.1 g, 92.0 mmol) in anhydrous THF (100 mL) was treated dropwise with diethyl azodicarboxylate (18.1 mL, 92.0 mmol) and the mixture heated to 50° C. for 40 minutes. After this time, the reaction mixture was concentrated in-vacuo and the resultant residue purified by flash chromatography (silica, 2×330 g column, ISCO, 0-10% ethyl acetate in dichloromethane). The resultant product was further purified by trituration with diethyl ether to afford the title compound as an off-white solid (17.6 g, 78%). 1H NMR (300 MHz, CDCl3): 9.57 (s, 1H), 8.76 (d, J=2.3 Hz, 1H), 8.57 (d, J=2.3 Hz, 1H), 8.23-8.22 (m, 2H), 7.64-7.63 (m, 1H), 7.53-7.51 (m, 2H), 5.20-5.20 (m, 1H), 4.07 (d, J=13.6 Hz, 2H), 3.06 (t, J=12.1 Hz, 2H), 2.20-2.19 (m, 2H), 1.85-1.85 (m, 2H), 1.47 (s, 9H).

Provenance & Evidence