反応 #4981

反応方程式

2,4-dihydroxy-3-methylbenzaldehyde

Phosphoric acid

→

solid

収率 72.0%

2,4-dimethylresorcinol

収率 72.0%

溶媒

isopropanol

反応条件

後処理

1. 1
   温度cooled in a 5 L 3-neck flask
2. 2
   その他fitted with a magnetic stirrer
3. 3
   その他the solution was sparged with nitrogen
4. 4
   その他(c. 1.5 hour)
5. 5
   その他was again sparged with nitrogen
6. 6
   ろ過filtered through Celite®
7. 7
   洗浄the resulting solution washed with water (4×100 mL)
8. 8
   抽出The water washes were back-extracted with ethyl acetate
9. 9
   乾燥the combined organic layers dried over sodium sulfate

実験手順

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).

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