Simple and effective method for high-selectivity removal of alpha-monomethyl of 2,6-dimethyl-4-pyridone derivative

Abstract

The invention discloses a simple and effective method for high-selectivity removal of an alpha-monomethyl of a 2,6-dimethyl-4-pyridone derivative. The simple and effective method comprises that an alpha-monomethyl of a 2,6-dimethyl-4-pyridone derivative is removed by oxygen as an oxidizing agent in the presence of anhydrous ferric chloride as a catalyst with heating; and after the reaction, cooling, extraction and separation processes are carried out so that a 6-methyl pyridone derivative is obtained simply and has a high yield. The simple and effective method has the advantages that there is only a reaction step; a flow is simple; the raw materials and the catalyst are cheap and easily available chemical materials; and a reaction organic solvent can be recovered easily and be recycled so that a reaction process is clean and efficient and large-scale industrial production can be realized.

Description

technical field [0001] The invention relates to a method for removing α-monomethyl of 2,6-dimethyl-4-pyridone derivatives, specifically using oxygen as an oxidant and anhydrous ferric chloride as a catalyst, and using DMSO as a solvent A method for removing a methyl group at the α-position of a 2,6-dimethyl-4-pyridone derivative. The method has the advantages of environmental friendliness, good compatibility of important functional groups, and good regioselectivity. Background technique [0002] 4-Pyridone derivatives have diverse biological activities and are widely used in chemical and chemical fields such as medicine and pesticides. In the pharmaceutical industry, it can be used to produce the anti-atherosclerotic drug Xuemaining. It can also be used to produce the broad-spectrum anthelmintic drug Qupinujing which is effective against roundworms, fasciola brucei, whipworms and pinworms. As well as cortisone acetate, hydrocortisone, niacin, ashbelin, and more. 2,6-luti...

AI Technical Summary

Problems solved by technology

At present, there are a large number of references to report the synthesis methods of pyridine and its derivatives, but some methods inevitably introduce groups such as methyl groups at the α-position of pyridine

There are literature reports on the method of removing the α-methyl group of pyridine in one step: such as: Suvorov, B.V.; Glubokovskikh, L.K.; Kan, I.I.; 11), 2451-2454, 2293-2295; Suvorov, B.V.; Glubokovskikh, L.K.; Kan, I.I., J.Appl.Chem.USSR (Engl.Transl.); 1980, 53(11), 2519-2521, 1866- In 1867, at a high temperature of 380 ° C, under the catalysis of vanadium pentoxide, titanium dioxide and tin dioxide, pyridine α-methyl was oxidized and removed, but the yield was less than 5%

[0004] In summary, the existing one-step and step-by-step removal of pyridyl α-methyl literature methods have some shortcomings, such as the need for high reaction temperature and the use of excessive strong base and strong acid, etc.

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