Diethyl Ether → Methyl 3-Benzyl-1,2,3,3a,4,5-hexahydro-4-(2,2-dimethyl-3-hydroxypropyl)-7H-pyrrolo (2,3-d) carbazole-6-carboxylate

Participants

Reaction Steps

To a solution of 873 mg (1.56 mmol) of methyl 3-benzyl-1,2,3,3a,4,5-hexahydro-4-[2,2-dimethyl-3-(t-butyldimethylsilyloxy)propyl]-7H-pyrrolo(2,3-d)carbazole-6-carboxylate in 30.5 mL of THF and 15 mL of water was added 5.24 g (20 eq) of p-toluenesulfonic acid. The reaction mixture was stirred for 90 min. At 20° C. and saturated aqueous K2CO3 solution was added until a pH=9-10 was obtained. Ethyl ether (100 mL) was added and the two layers were separated. The aqueous layer was extracted once with 100 mL of ethyl ether and twice with 100 mL of CH2Cl2. The combined organic layers were dried over MgSO4 and the solvents evaporated in vacuo (aspirator). The crude product was purified by column chromatography on silica gel (40 g). Elution with CH2Cl2 followed by ethyl ether gave 0.678 g (97.5%) of the title compound as a white foam. TLC: (Silica) Rf 0.50 (ethyl ether), detection with CAS (blue with developing yellow center), UV (long and short wave length).

Provenance & Evidence