Sulfuric Acid → HCID 20721231, compound

Participants

Reaction Conditions

Reaction Steps

(2R)-Amino-2-methyl-4-[5-(5-phenylpent-1-ynyl)thiophen-2-yl]butan-1-ol (387 mg, 1.18 mmol) obtained in Example 49 was dissolved in methanol (4 ml), and 6N sulfuric acid (4 ml) was added thereto followed by heating under reflux for 4 hours. The reaction solution was cooled to 0° C. and made alkaline (pH 14) with a 1N aqueous sodium hydroxide solution, and the resulting solution was extracted with dichloromethane. The dichloromethane layer was dried over anhydrous sodium sulfate, and the solvent was evaporated in vacuo. The residue was purified by chromatography on a silica gel column (Chromatorex NH (100-200 mesh)) (elution solvent; dichloromethane:methanol=1:0−50:1) to afford (2R)-amino-2-methyl-4-[5-(5-phenylpentanoyl)thiophen-2-yl]butan-1-ol (336 mg, 82% yield). This compound was dissolved in methanol, and oxalic acid (88 mg, 0.97 mmol) was added thereto to precipitate crystals. The crystals were recrystallized from methanol to afford-the title compound (332 mg, 78% yield) as white crystals.

Provenance & Evidence