Hydrochloric Acid → 1H-Cyclopropa[4,5]cyclopenta[1,2]pyrazole-3-carboxylic acid, 4,4a,5,5a-tetrahydro-, ethyl ester, (4aR,5aR)-

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Reaction Conditions

Reaction Steps

(1R,5S)-Bicyclo[3.1.0]hexan-2-one (1.000 g, 10.40 mmol) was taken up in ethanol (40 mL) and potassium tert-butoxide (1.0 M in THF) (13.00 mL, 13.00 mmol) was added, followed by diethyl oxalate (1.413 mL, 10.40 mmol). The resulting solution was heated and stirred for 1 h at 70° C. Hydrazine (10.40 mL, 10.40 mmol) was then added, followed by hydrochloric acid (ca 3 M aqueous) (10.40 mL, 31.2 mmol). The solution was stirred at 70° C. for 1 h and purified by HPLC to give the title compound (356 mg, 1.852 mmol, 17.80% yield) as a solid. LCMS m/z=193.3 [M+H]+.

Provenance & Evidence