2-(Ethoxymethylene)propanedinitrile → 5-amino-1-isopropyl-1H-pyrazole-4-carbonitrile

Participants

Reaction Steps

(Ethoxymethylene)malononitrile (12.83 g, 105 mmol) and isopropylhydrazine hydrochloride (11.06 g, 100 mmol) were combined in EtOH (250 mL). Diisopropylethylamine (36.6 mL, 210 mmol) was added drop-wise, resulting in some warming of the reaction mixture. The reaction was allowed to stir for about 18 h at room temp. Volatiles were then removed in vacuo, and the resulting viscous yellow oil was dissolved in dichloromethane and loaded onto a short column of silica gel. The column was eluted with dichloromethane (about 300 mL), followed by a 1:1 mixture of EtOAc and hexanes (about 750 mL), and the EtOAc:hexanes eluant was concentrated under reduced pressure to provide C20 as a pale yellow solid. Yield: 12.1 g, 80.6 mmol, 81%. LCMS m/z 151.1 (M+1). 1H NMR (400 MHz, DMSO-d6) δ 1.26 (d, J=6.6 Hz, 6H), 4.41 (septet, J=6.5 Hz, 1H), 6.52 (br s, 2H), 7.53 (s, 1H).

Provenance & Evidence