Method for preparing 5-bromoacetylsalicylic acid methyl ester
A technology of methyl bromoacetylsalicylate and methyl salicylate, which is applied in the field of preparation of methyl 5-bromoacetylsalicylate, can solve the problems of high corrosion of equipment, complicated operation process, and low synthesis efficiency. Achieve the effect of low cost, high synthesis yield and mild reaction conditions
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Embodiment 1
[0026] In 100ml of anhydrous dichloromethane, add 17.4g (0.086mol) of 2-bromoacetyl bromide and 26.4g (0.198mol) of aluminum trichloride, heat up to reflux, slowly drop in 10g (0.066mol) of methyl salicylate , The dropwise addition was completed, and the reaction was continued for 14h. Cool down to room temperature, slowly pour the reaction solution into a mixture containing equal volumes of water, ice and dichloromethane, adjust the pH to 1-2 with 12M hydrochloric acid, and continue stirring for 30 minutes. Extract three times with an equal volume of dichloromethane, combine the organic phases, and concentrate to obtain a brownish-yellow viscous solid crude product, add 2 times the volume of petroleum ether to wash, filter with suction, and dry the filter cake to obtain 16.7 g of a light yellow solid. 92.7%.
[0027] Its structural identification data are as follows:
[0028] mp: 88.5-90.0°C;
[0029] MS (ESI - ):272(M*-H);
[0030] 1 H-NMR (400MHz, CDCl 3 )δ11.3 (1H, ...
Embodiment 2
[0032] In 100ml of anhydrous dichloromethane, add 26.6g (0.132mol) 2-bromoacetyl bromide and 35.2g (0.264mol) aluminum trichloride, at 25 ℃, slowly drop into 10g (0.066mol) methyl salicylate , The dropwise addition was completed, and the reaction was continued for 24h. The reaction solution was slowly poured into a mixed solution containing an equal volume of water, ice and dichloromethane, and the pH was adjusted to 1-2 with 12M hydrochloric acid, and the stirring was continued for 30 minutes. Extract three times with an equal volume of dichloromethane, combine the organic phases, and concentrate to obtain a brown-yellow viscous solid crude product, add 2 times the volume of petroleum ether to wash, filter with suction, and dry the filter cake to obtain 14.8 g of a light yellow solid. 82.1%.
Embodiment 3
[0034] In 100ml of anhydrous dichloromethane, add 17.4g (0.086mol) of 2-bromoacetyl bromide and 26.4g (0.198mol) of aluminum trichloride, heat up to reflux, slowly drop in 10g (0.066mol) of methyl salicylate , The dropwise addition was completed, and the reaction was continued for 24h. Cool down to room temperature, slowly pour the reaction solution into a mixture containing equal volumes of water, ice and dichloromethane, adjust the pH to 1-2 with 12M hydrochloric acid, and continue stirring for 30 minutes. Extract three times with an equal volume of dichloromethane, combine the organic phases, and concentrate to obtain a brown-yellow viscous solid crude product, add 2 times the volume of petroleum ether to wash, filter with suction, and dry the filter cake to obtain 15.4 g of a light yellow solid. 85.5%.
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