Diisopropylethylamine → [4-(4-Tert-butylamino-quinazolin-2-ylamino)-cyclohexyl]-carbamic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

To a suspension of cis-(4-amino-cyclohexyl)-carbamic acid tert-butyl ester (122 mg, 0.57 mmol) in 2-propanol (2 mL) were added tert-butyl-(2-chloro-quinazolin-4-yl)-amine (100 mg, 0.42 mmol) and diisopropylethylamine (180 μL, 1 mmol) and the mixture was heated at 170° C. for 1 hr using a Smith Microwave Synthesizer. The resulting solution was concentrated and purified by column chromatography (silica gel, 3% MeOH in CH2Cl2) to give [4-(4-tert-butylamino-quinazolin-2-ylamino)-cyclohexyl]-carbamic acid tert-butyl ester (112 mg, 65%) as a yellow solid. To a suspension of cis-[4-(4-tert-butylamino-quinazolin-2-ylamino)-cyclohexyl]-carbamic acid tert-butyl ester (95 mg, 0.23 mmol) in CH2Cl2 (3 mL) was added trifluoroacetic acid (2 mL) dropwise. The reaction mixture was stirred at ambient temperature for 2 hr. The solution was concentrated, alkalized with saturated aqueous NaHCO3 and 1 M aqueous sodium hydroxide (pH=9), and the aqueous layer was extracted with CH2Cl2 (three times). The combined organic layer was dried over MgSO4, filtered, and concentrated. The solid was collected by filtration to give cis-N2-(4-amino-cyclohexyl)-N-tert-butyl-quinazoline-2,4-diamine (44.6 mg, 53%) as a yellow solid.

Provenance & Evidence