Sulfuric Acid → HCID 20692715, compound

Participants

Reaction Conditions

Reaction Steps

The product of example 12, 4-(4-Fluorophenyl)-5-(4-pyridyl) 2-(4-hydroxy-1-methylpiperidin-4-yl)imidazole (22.2 g; 63 mmol) is dissolved in 1-butanol (1 l) upon warming to 40° C. H2SO4 conc (27.8 g; 283 mmol) is added dropwise and the initially resulting suspension is refluxed for 3.5 h, while distilling off ˜200 ml of 1-butanol. The reaction mixture is cooled to room temperature and poured on a saturated solution of Na2CO3 (500 ml). The aqueous phase is extracted with ethyl acetate and the combined organic phases dried over Na2SO4, filtered and evaporated to dryness. Purification by chromatography (SiO2; TBME/MeOH/NH3conc. 96/4/0.4 to 70/30/1) yields the title compound as yellow crystals (15.5 g; 60.3%). A sample is recrystallized from CH2Cl2/TBME to render colorless crystals: m.p. 177° C.

Provenance & Evidence