63394-09-2Relevant articles and documents
A trimethoprim intermediate 3, 5 - dibromo - 4 - hydroxybenzaldehyde preparation
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Paragraph 0020; 0021; 0022; 0023; 0024; 0025-0028, (2017/08/25)
The invention provides a preparation method of trimethoprim midbody 3,5-dibromo-4-hydroxy benzaldehyde. The preparation method comprises the following steps of sequentially adding paracresol, ethanoic acid and zinc chloride in a reaction container; uniformly stirring; slowly adding benzyl trimethyl ammonium tribromide after cooling to the temperature of 0 DEG C; reacting for 1-2 hours at the temperature of 10-15 DEG C; heating to the temperature of 90-95 DEG C and reacting for 1.5-3 hours; performing reduced pressure distillation on reaction liquid to recycle acetic acid; adding water in a substrate, stirring, heating and performing backflow hydrolysis for 2-4 hours; cooling to room temperature; and filtering, washing and drying to obtain the 3,5-dibromo-4-hydroxy benzaldehyde. Reaction conditions of the preparation method are gentle, a technology is simple, reaction speed is high, the purity of products is above 98%, yield is above 93%, and BTMABr3 serves as a bromination reagent and replaces bromine with high toxicity. The preparation method has the advantages of safety, zero toxicity and environmental protection.
Synthesis of 3,4,5-Trimethoxybenzaldehyde
Manchand, Percy S.,Belica, Peter S.,Wong, Harry S.
, p. 2659 - 2666 (2007/10/02)
The copper(I)-catalyzed exchange of bromine by methoxide in 5-bromovanillin and in 3,5-dibromo-4-hydroxybenzaldehyde provides an efficient method for preparing 3,5-dimethoxy-4-hydroxybenzaldehyde, from which 3,4,5-trimethoxybenzaldehyde is obtained by methylation with dimethylsulfate.
