Lithium hydroxide, monohydrate → 6-(Tert-butoxycarbonyl)-5-(2,4-dichlorophenyl)-7-methylimidazo[1,2-a]pyrimidine-2-carboxylic acid

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Reaction Steps

To a stirred solution of 6-tert-butyl 2-ethyl 5-(2,4-dichlorophenyl)-7-methylimidazo[1,2-a]pyrimidine-2,6-dicarboxylate (Example 54, Step 4, 3 g, 6.66 mmol) in THF (6 mL) and MeOH (2 mL) was added LiOH.H2O (0.42 g, 9.99 mmol) in H2O (2 mL). After 1 h, the reaction was quenched by 1N HCl till pH to 2. The organic volatiles were removed under reduced pressure and the residue was dissolved in EtOAc. The organic layer was washed with satd aq NH4Cl and brine prior to drying over MgSO4. Filtration, concentration under reduced pressure and recrystallization from 1:2 EtOAc/hexanes afforded 6-(tert-butoxycarbonyl)-5-(2,4-dichlorophenyl)-7-methylimidazo[1,2-a]pyrimidine-2-carboxylic acid (2.78 g, 90%) as a cream solid.

Provenance & Evidence