Three syntheses of 3,8-dimethyl-1H-pyrano[4,3-b][1]benzopyran-10-one, a model for the synthesis of the fungal metabolite, fulvic acid
作者:Francis M. Dean、Mohammad Al-Sattar、Dennis A. Smith
DOI:10.1039/c39830000535
日期:——
Compouds with the 1H-pyrano[4,3-b][1]benzopyran-10-one nucleus characteristic of fulvic acid have been prepared by three methods from chromone precursors; the characteristic steps are (i) the acetylation of the 2-methyl group of 3-methoxymethyl-2,6-dimethylchromone by acetyl chloride and lithium di-isopropylamide at –70 °C, (ii) the acetylation of the 2-methyl group of 3-chloromethyl-2,6-dimethylchromone
由色酮前体通过三种方法制备了具有黄腐酸特征的1 H-吡喃并[4,3- b ] [1]苯并吡喃-10-酮核。特征步骤是(i)在–70°C下通过乙酰氯和二异丙基氨基锂将3-甲氧基甲基-2,6-二甲基色酮的2-甲基乙酰化,(ii)将2-甲基乙酰化N,N-二甲基乙酰胺在磷酰氯中进行3-氯甲基-2,6-二甲基色酮的酸水解,然后进行酸水解;(iii)(最佳途径)将2-甲氧基丙烯反向Diels-Alder加成至3-甲酰基-6-甲基色酮和产物的铑催化异构化,以重新获得色酮核。