2-Aminoadamantane hydrochloride → 1-tert-butyl-5-chloro-1H-pyrazole-4-carboxylic acid adamantan-2-ylamide

Participants

Reaction Steps

tert-Butyl-5-chloro-1H-pyrazole-4-carboxylic acid (Intermediate 9, 0.5 g, 2.47 mmol) was dissolved in a mixture of dry dichloromethane (12 mL) and dry DMF (3 mL). DIPEA (2.6 mL, 14.9 mmol) and TSTU (0.9 g, 2.7 mmol) were added to the above mixture. After the mixture was stirred for 1 h, the appearance of active ester was detected by LC-MS. Then 2-aminoadamantane hydrochloride (0.44 g, 2.34 mmol) was added. After another 2 hours water was added and the organic layer was separated. The aqueous layer was extracted twice with dichloromethane. The combined organic phases were dried under vacuum and purified by C-18 reverse phase preparative-HPLC with a gradient of 10-100% acetonitrile/water to give 1-tert-butyl-5-chloro-1H-pyrazole-4-carboxylic acid adamantan-2-ylamide (650 mg, 83%). Mass spectrum: m/z: 336.2 (M+1).

Provenance & Evidence