Sodium hydride → HCID 178423918, compound

Participants

Reaction Steps

Sodium hydride (0.35 g, 60% suspension in mineral oil) was added in one portion to a stirred solution of 5-amino-1-(2-hydroxyethyl)-4-(4-methylphenyl)-1-H-pyrazol-3-ol(1.0 g) (Preparation 32) in anhydrous N,N-dimethylacetamide (20 ml) under a nitrogen atmosphere at room temperature. The initial effervescence observed subsided after 2-3 minutes and an orange/brown mixture resulted. After a further 7 minutes, tert-butyldimethylsilyl chloride (0.65 g) was added to the mixture in one portion and the reaction mixture was stirred at room temperature for 2 hours. Saturated aqueous ammonium chloride (50 ml) was added to the reaction mixture and the resulting aqueous medium was extracted with ethyl acetate (2×50 ml). The combined organic extracts were washed with water (40 ml), brine (40 ml) then dried over magnesium sulfate, filtered and concentrated under reduced pressure. The residue was recrystallised from dichloromethane/hexane to give the title compound as a white solid (0.66 g). m.p. 193.5-195° C.

Provenance & Evidence