تفاعل #6437

معادلة التفاعل

1-[4-(1,1-dimethylethyl)-2 methyl-5-oxazolyl]-2,2-dimethyl-1 propanone

ammonium hydroxide

→

4,6-bis(1,1-dimethylethyl)-5-hydroxy-2-methylpyrimidine

المردود 75.0%

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةThe reaction mixture is cooled
2. 2
   أخرىthe excess ammonia is evaporated on the rotovap
3. 3
   أخرىThe pH of the resulting mixture is adjusted to pH 6 with concentrated HCl with ice bath
4. 4
   درجة الحرارةcooling
5. 5
   استخلاصThe product is extracted into ether (3×250 mL)
6. 6
   تجفيفthe organic layer is dried (MgSO4)
7. 7
   أخرىevaporated
8. 8
   أخرىThe residue is purified by flash chromatography (silica, 7% EtOAc/hexane)

الإجراء التجريبي

A mixture of 1-[4-(1,1-dimethylethyl)-2 methyl-5-oxazolyl]-2,2-dimethyl-1 propanone (8.5 g, 38 mmol) and concentrated ammonium hydroxide (100 mL) is heated at 180° C. for 36 hours in a steel bomb. The reaction mixture is cooled and the excess ammonia is evaporated on the rotovap. The pH of the resulting mixture is adjusted to pH 6 with concentrated HCl with ice bath cooling. The product is extracted into ether (3×250 mL) and the organic layer is dried (MgSO4) and evaporated. The residue is purified by flash chromatography (silica, 7% EtOAc/hexane) to give pure 4,6-bis(1,1-dimethylethyl)-5-hydroxy-2-methylpyrimidine (6.35 g, 75%) as a partial hydrate; mp 62°-65° C.

المصدر