2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 1-(2,4,5-trimethoxyphenyl)propan-1-one

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Reaction Steps

In order to further increase the yield of α-asarone, an alternative route appears to prepare intermediate 1-(2,4,5-trimethoxy)phenyl-1-propanone (isoacroramone) by treating 2,4,5-trimethoxyphenylpropane with DDQ in aqueous organic solvent which upon treatment with sodium borohydride into 1-(2,4,5-trimethoxyphenyl-1-hydroxypropane followed by acidic dehydration towards formation of α-asarone. The structure of 1-(2,4,5-trimethoxy)phenyl-1-propanone, a crystalline solid (mp 109-110° C.), was confirmed on the basis of spectral data (Example IV) which is later on discovered as a naturally occurring rarer phenylpropanoid, isolated from Acorus tatarinowii as a light yellowish viscous gum, however, our method afforded isoacoramone as a crystalline solid with the similar spectral data as natural isoacoramone (Jinfeng, Hu and Xiaozhang, Feng, Planta Medica, 66, 662-664 (2000)). It is also worthwhile to mention that the formation of 1-(2,4,5-trimethoxyphenyl)-1-propanone in a single step from phenylalkane i.e. 2,4,5-trimethoxypropane opens new route for the synthesis of phenylpropanone derivatives which is, in fact, a mild, simple and free from drawbacks generally exist with reported synthetic methods and some of reported methods are:

Provenance & Evidence