Imidazole → HCID 68572249, compound

Participants

Reaction Conditions

Reaction Steps

To a sol. of compound C4 (7.68 g, 14.7 mmol) in EtOH (80 mL) was added aq. 1M NaOH (80 mL). The reaction mixture was heated to 80° C. overnight. The mixture was partially concentrated under reduced pressure. The residue was acidified with aq. 3M HCl, and this aq. phase was extracted with EtOAc (5 mL). The organic extracts were dried over MgSO4, filtered, and the solvents were removed under reduced pressure. To a sol. of this crude product (6.5 g) in dry DMF (60 mL) was added imidazole (4.01 g, 58.9 mmol), and the mixture was cooled to 0° C. TBDMS-Cl (5.55 g, 36.8 mmol) was added, and the reaction mixture was stirred at rt for 2 h. Imidazole (1.5 g, 22.1 mmol) and TBDMS-Cl (2.23 g, 14.8 mmol) were added, and the mixture was stirred for 3 h. The reaction mixture was cooled to 0° C. (ice-water bath), and aq. sat. NH4Cl was slowly added. The resulting mixture was extracted with heptane/Et2O and the combined org. extracts were dried over MgSO4, filtered, and concentrated under reduced pressure. The crude product was dissolved in a mixture of THF (60 mL), MeOH (20 mL) and water (20 mL). To this sol. was added K2CO3 (1.017 g). The mixture was stirred for 2 h. The mixture was concentrated under reduced pressure. The residue was dissolved in TBME, and was washed with aq. sat. NH4Cl. The aq. layer was extracted with TBME. The combined org. extracts were dried over MgSO4, filtered, and concentrated under reduced pressure. Drying the residue under high vacuum yielded the title compound (10 g, quantitative) that was used without purification. LC-MS: tR=1.12 and 1.16 min; ES+: 608.32.

Provenance & Evidence