تفاعل #4981

معادلة التفاعل

2,4-dihydroxy-3-methylbenzaldehyde

Phosphoric acid

→

solid

المردود 72.0%

2,4-dimethylresorcinol

المردود 72.0%

المذيبات

isopropanol

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةcooled in a 5 L 3-neck flask
2. 2
   أخرىfitted with a magnetic stirrer
3. 3
   أخرىthe solution was sparged with nitrogen
4. 4
   أخرى(c. 1.5 hour)
5. 5
   أخرىwas again sparged with nitrogen
6. 6
   ترشيحfiltered through Celite®
7. 7
   غسيلthe resulting solution washed with water (4×100 mL)
8. 8
   استخلاصThe water washes were back-extracted with ethyl acetate
9. 9
   تجفيفthe combined organic layers dried over sodium sulfate

الإجراء التجريبي

A solution of 2,4-dihydroxy-3-methylbenzaldehyde (30.0 g, 197 mmol) with isopropanol (3 L) was ice-cooled in a 5 L 3-neck flask fitted with a magnetic stirrer. Phosphoric acid (4 mL) and d10% palladium on carbon were added and the solution was sparged with nitrogen, then hydrogen. When uptake was judged to be complete (c. 1.5 hour) the solution was again sparged with nitrogen and then filtered through Celite®. The solvent was stripped off, the residue taken up in ethyl acetate, and the resulting solution washed with water (4×100 mL). The water washes were back-extracted with ethyl acetate and the combined organic layers dried over sodium sulfate and stripped down. Sublimation (95°, 0.05 torr) afforded a colorless solid (19.6 g, 72%). M.p. 107°-8° C. (Lit. 108°-109° C. [W. Baker et al., J. Chem. Soc., 2834-5 (1949).]). NMR (DMSO-d6): δ 1.969 (s, 3H), 2.037 (s, 3H), 6.220 (d, J=8.1 hz, 1H), 6.637 (d, J=8.1 hz, 1H), 7.929 (s, 1H), and 8.785 (s, 1H).

المصدر