Single acylation method of dihydroxybenzene alkyl ketone
A technology of dihydroxyphenyl alkyl ketone and hydroxy phenyl alkyl ketone, which is applied in the field of preparation of organic intermediates, can solve the problem of low yield of monoacylation, and achieve the effect of high selectivity and high yield
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Embodiment 1
[0019] Monoacylation of 2,4-Dihydroxyacetophenone
[0020] Place 3.5g (0.056mol) of boric acid in 50ml of glacial acetic acid and stir at 60°C for 2h. Then it is cooled to room temperature, and the active boronic acid derivative is prepared like this, and the next step reaction is directly carried out without processing. Add 2 g (0.013 mol) of 2,4-dihydroxyacetophenone to the solution of the active boronic acid derivative, stir at room temperature for 30 min, and filter. The filtrate was spin-dried under a vacuum pump to obtain the 4-position monoacylated product of 2,4-dihydroxyacetophenone, 2.2 g, with a yield of 99%. 1 H NMR (300MHz, CDCl 3 ): δ2.28(s, 3H, CH 3 ), 2.58 (s, 3H, CH 3 ), 6.70 (s, 2H, Ph), 7.72 (s, 1H, Ph), 12.41 (s, 1H, OH); melting point: 72.3°C, literature value 74-76°C.
Embodiment 2
[0022] Monoacylation of 3,5-Dihydroxyacetophenone
[0023] To 2.0 g (0.013 mol) of 3,5-dihydroxyacetophenone was added 0.104 g (0.026 mol) of NaOH and 20 mL of water. Cool in an ice bath to 0°C, and add 1.4 g (0.013 mol) of acetic anhydride. The solution was stirred for 40 min, and 10% H was added 2 SO 4 The solution was acidified and an ice-water bath was maintained throughout. The product was obtained by filtration and washed with ice water. After recrystallization from water, 1.5 g of compound 6 was obtained with a yield of 60%. 1 H NMR (300MHz, CDCl 3 ): δ2.28(s, 3H, CH 3 ), 2.58 (s, 3H, CH 3 ), 7.03, 7.26, 7.35 (s, 1H, Ph), 9.20 (s, 1H, OH); melting point: 78°C.
Embodiment 3
[0025] Monoacylation of 2,4-Dihydroxyacetophenone
[0026] Place 0.02mol boric acid in 30ml propionic acid and stir at 60°C for 2h. Then it is cooled to room temperature, and the active boronic acid derivative is prepared like this, and the next step reaction is directly carried out without processing. Add 0.01 mol of 2,4-dihydroxyacetophenone to the solution of active boric acid derivatives, stir at room temperature for 30 min, and filter. The filtrate was spin-dried under a vacuum pump to obtain the 4-position monoacylated product of 2,4-dihydroxyacetophenone. The reaction formula is as follows:
[0027]
[0028] Among them, R 1 is C 3 the alkyl group, R 2 is C 3 of alkyl.
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