Réaction #91635

Équation de réaction

p-tolylhydrazine hydrochloride

4,4-dimethyl-3-oxopentanenitrile

HCl

→

3-tert-butyl-1-p-tolyl-1H-pyrazol-5-amine

Rendement 53.0%

Solvants

EtOH

iso-hexane

Conditions de réaction

Traitement

1. 1
   Températureat reflux overnight
2. 2
   Concentrationconcentrated in vacuo to c.a
3. 3
   TempératureThe reaction mixture was then cooled in an ice-bath
4. 4
   ExtractionThe reaction mixture was extracted with diethyl ether (500 mL)
5. 5
   Lavagethe organic phase washed with water (2×300 mL)
6. 6
   Séchagebefore being dried over magnesium sulphate
7. 7
   Concentrationconcentrated in vacuo
8. 8
   Autreto afford an orange solid
9. 9
   workup.STIRRINGstirred
10. 10
    Températureat reflux for 2.5 h
11. 11
    Températurebefore being cooled
12. 12
    Filtrationfiltered whilst still hot

Mode opératoire

To a stirred solution of p-tolylhydrazine hydrochloride (100 g, 630 mmol) in EtOH (1251 mL) was added 4,4-dimethyl-3-oxopentanenitrile (88 g, 699 mmol) and HCl (62.5 mL, 750 mmol). The resulting mixture was stirred at reflux overnight. The reaction mixture was cooled to room temperature and concentrated in vacuo to c.a. ⅓ of the original volume. The reaction mixture was then cooled in an ice-bath and taken to c.a. pH 8-9 with 6M aq NaOH. The reaction mixture was extracted with diethyl ether (500 mL) and the organic phase washed with water (2×300 mL) before being dried over magnesium sulphate and concentrated in vacuo to afford an orange solid. The solid was suspended in iso-hexane and stirred at reflux for 2.5 h before being cooled and filtered whilst still hot to yield the subtitle product 3-tert-butyl-1-p-tolyl-1H-pyrazol-5-amine as a pale brown solid (76.5 g, 52%); Rt 1.31 min (Method 1); m/z 230 (M+H)+ (ES+); 1H NMR δ: 1.20 (9H, s), 2.32 (3H, s), 5.10 (2H, br s), 5.35 (1H, s), 7.24 (2H, d), 7.42 (2H, m).

Source