Sulfuric Acid → HCID 59854714, compound

Participants

Reaction Steps

Compound 03-6 (3.64 g, 10.9 mmol) was suspended in a mixture of MeOH (450 mL) and MeCN (100 mL). H2SO4 (1.5 mL) was added and the mixture was stirred under a N2-atmosphere, while monitoring the reaction by HPLC. After 7 days the conversion was complete and the mixture was concentrated to half of the original volume. Water was added and the pH was cautiously adjusted to 8 with conc. NH4OH. The aqueous layer was extracted with EtOAc (3×100 mL). The combined organic layers were washed with H2O (100 mL), brine (100 mL) and dried over Na2SO4. The solvent was removed in vacuo to give the crude product as a green sticky oil, which was purified by column chromatography (SiO2, EtOAc/Hept=1/4+1% Et3N). The product fractions were pooled and the solvent was removed in vacuo. The residue was dissolved in Et2O (50 mL) and the solution was washed with conc. aq. NH4Cl (2×50 mL) and brine (50 mL) to remove residual NEt3. After drying over Na2SO4, the solvent was removed in vacuo to give a-3 (2.6 g, 8.9 mmol, 82%) as a greenish grey solid.

Provenance & Evidence