Ethanol → 8-tert-Butyl-6,7-dihydropyrrolo(3,2-e)-5-methylpyrazolo(1,5-a)pyrimidine-3-carbonitrile

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Reaction Conditions

Reaction Steps

(ii-1) 2.7 g (0.01 mol) of Compound (VI) [R2 =CH3, R3 =CN], 2 ml of triethylamine, 3.2 ml of tert-butylamine, and 15 ml of anhydrous ethanol were placed in a closed tube and heated at 85° C. in a water bath for 8 hours. Then the tube was opened, and 100 ml of methyl ethyl ketone was added to the reaction solution. The mixed solution was warmed and subjected to filtration. The filtrate was purified over a chromatographic column packed with 10 g of silica gel (pH=7, 200 mesh) using methyl ethyl ketone in advance. The eluant was then evaporated to obtain 2.4 g of 8-tert-butyl-3-cyano-6,7-dihydro-2,5-dimethyl-8H-pyrrolo[3,2-e]pyrazolo[1,5-a]pyrimidine [R1 =C(CH3)3, R2 =CH3, R3 =CN in formula (I)] (Compound 2 of this invention) as yellowish orange plate crystals having a melting point of 229°-230° C. at a yield of 80.0%.

Provenance & Evidence