Method for preparing (2E,4E)-2-methyl-6-oxo-2,4-heptadienal

Abstract

The invention discloses a synthetic method of (2E, 4E)-2-methyl-6-oxo-2 and 4- heptadiene aldehyde. The method of the invention comprises the processes: 2-methacrylate and alkyl methacrylate ester is transformed to 3-iodine-2-methacrylate and alkyl methacrylate esters through bromine addition, elimination and iodine exchanging; then a coupling reaction is carried out between the 3-iodine-2-methacrylate and alkyl methacrylate esters and methyl vinyl ketone to generate the (2E, 4E)-2-methyl-6-oxo-2 and the 4- heptadiene aldehyde; the (2E, 4E)-2-methyl-6-oxo-2 and the 4-heptadiene aldehyde are transformed to (2E, 4E)-2-methyl-2, 4-heptadiene-1 and 6-menthandiol through a reduction reaction; the (2E, 4E)-2-methyl-2, the 4-heptadiene-1 and the 6- menthandiol are oxidized to obtain the (2E, 4E)-2-methyl-6-oxo-2 and the 4- heptadiene aldehyde.

Description

technical field [0001] The invention relates to a preparation method of an organic compound, in particular to a preparation method of (2E,4E)-2-methyl-6-oxo-2,4-heptadienal. Background technique [0002] US Pat. No. 7,132,458 discloses that (2E,4E)-2-methyl-6-oxo-2,4-heptadienal is a product of oxidative degradation of vitamin A and carotene, which has medicinal activity. US7132458 discloses that it has the functions of cell recognition, cell growth inhibition, and anticancer; WO2003034570 discloses that it can promote growth and improve food conversion; WO2005079143 discloses that it is used for improving skin; WO2007112587 discloses that it is effective as a nutritional supplement Composition, used to treat or alleviate weight loss caused by illness, childbirth and other reasons. [0003] Synthesizing (2E, 4E)-2-methyl-6-oxo-2,4-heptadienal in the prior art has the following methods: [0004] It is prepared by oxidation of carotene or vitamin A. This method has a low yie...

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Problems solved by technology

[0008] But the deficiency of this method is: 1) its starting material 2, the commercial chemical raw material of 2-dimethoxyacetaldehyde and easy and easy to get, its synthesis is comparatively cumbersome; 2) the first step of synthetic process is a Aldol condensation reaction, because the raw material propionaldehyde is easy to condense itself, and it is also easy to condense with the product to produce by-products, which makes the reaction very strict on the reaction temperature, sample addition speed, reaction concentration, reaction time, etc., resulting in inconvenient operation

[0012] This method obtains the desired product by allylic oxidation, although only one-step reaction is needed, and the route is relatively short, but it still has great deficiencies: (1) the raw materials of this method need to be synthesized by multiple reactions; 2) There is no good method for the oxidation of the allylic position of the carbonyl compound of this polyene so far

This method uses enzyme-catalyzed oxidation, the yield of the target compound is only 17%, and it is difficult to separate from the main product epoxy compound

Existing chemical methods for allylic oxidation can only obtain very low yields or even fail to obtain the desired product for this substrate

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