2-(Ethoxymethylene)propanedinitrile → 5-amino-1-(3-chloro-2-methylphenyl)-1H-pyrazole-4-carbonitrile
Reaction equation
Cl.[Cl:2][C:3]1[C:4]([CH3:11])=[C:5]([NH:9][NH2:10])[CH:6]=[CH:7][CH:8]=1.C(O[CH:15]=[C:16]([C:19]#[N:20])[C:17]#[N:18])C>>[NH2:20][C:19]1[N:9]([C:5]2[CH:6]=[CH:7][CH:8]=[C:3]([Cl:2])[C:4]=2[CH3:11])[N:10]=[CH:15][C:16]=1[C:17]#[N:18]Participants
3
Conditions
- Temperature
- 0 °C
Procedure
(3-Chloro-2-methylphenyl)hydrazine hydrochloride (CAS no. 65208-12-0) (9 g, 46.61 mmol) was partitioned between EtOAc (100 mL) and NaOH (2M, aq) (60 mL). The organic layer separated and washed with water (50 mL), brine (50 mL), dried (MgSO4), filtered and concentrated. The resultant oil was suspended in MeOH (100 mL) under nitrogen at −5° C. 2-(Ethoxymethylene)malononitrile (5.69 g, 46.61 mmol) was added portionwise over 5 mins and the mixture stirred at ˜0° C. for 30 mins. The reaction mixture was allowed to warm to room temperature and then heated at reflux under nitrogen for 2 hours. The reaction mixture was allowed to cool and evaporated to dryness. The crude product was purified by flash silica chromatography, elution gradient 0 to 50% EtOAc in isohexane to afford the product(6.33 g, 58.4%). 1H NMR (400 MHz, DMSO) δ 2.02 (3H, s), 6.57 (2H, s), 7.25-7.32 (1H, m), 7.37 (1H, t), 7.58-7.64 (1H, m), 7.77 (1H); m/z (ES+) (M+H)+=233.28; HPLC tR=1.89 min.