Reaktion #91635

Reaktionsgleichung

p-tolylhydrazine hydrochloride

4,4-dimethyl-3-oxopentanenitrile

HCl

→

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

Ausbeute 53.0%

Lösungsmittel

EtOH

iso-hexane

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturat reflux overnight
2. 2
   Einengenconcentrated in vacuo to c.a
3. 3
   TemperaturThe reaction mixture was then cooled in an ice-bath
4. 4
   ExtraktionThe reaction mixture was extracted with diethyl ether (500 mL)
5. 5
   Waschenthe organic phase washed with water (2×300 mL)
6. 6
   Trocknenbefore being dried over magnesium sulphate
7. 7
   Einengenconcentrated in vacuo
8. 8
   Sonstigeto afford an orange solid
9. 9
   workup.STIRRINGstirred
10. 10
    Temperaturat reflux for 2.5 h
11. 11
    Temperaturbefore being cooled
12. 12
    Filtrationfiltered whilst still hot

Vorschrift

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).

Quelle