Method for synthesizing famciclovir intermediate

Abstract

The invention discloses a method for synthesizing a famciclovir intermediate. The famciclovir intermediate is prepared by using a novel synthesis route, the amount of a reducing agent can be reduced,reaction selectivity can be improved, and expensive reagents are avoided. By adopting the novel synthesis method, the yield of the famciclovir intermediate can be increased, and the production cost ofthe famciclovir intermediate can be lowered.

Description

technical field [0001] The invention relates to a synthetic method of a famciclovir intermediate. Background technique [0002] Famciclovir (Famciclovir) is an oral nucleoside broad-spectrum antiviral drug developed by British Smith Kline Company. It was first launched in the UK in 1993 for the treatment of herpes zoster and primary genital herpes. After oral administration, famciclovir is rapidly converted into penciclovir with antiviral activity, which has inhibitory effects on herpes simplex virus type I and type II and varicella zoster virus. [0003] There are many synthetic routes of famciclovir, among which the patent WO2007106561 and the literature Tetrahedron Letters, Vol26, No.35, pp4265-4268, 1985, and the literature Synthetic Communications, Vol34, No.4, pp.689-704, 2004 have reported synthesis route, as follows: [0004] . [0005] This route mainly has the following disadvantages: [0006] 1) Compound 1 has three ester bonds, and the reducing agent lithiu...

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Problems solved by technology

[0009] Since the two have similar structures and are liquids with high boiling points, they are not easy to separate by distillation

Patent EP141927 and the synthetic routes reported in the above-mentioned documents all need to be purified by column chromatography, which is cumbersome to operate, consumes a large amount of organic solvents, and has a low yield; therefore, the cost of producing famciclovir according to this route is relatively high

[0010] 3) The preparation of compound 4 from compound 3 requires the use of the reagent carbon tetrabromide, which is expensive and uneconomical in industrial production.

[0013] The yield of this route is improved when compound 2 is prepared from compound 6, but there is also the problem of selective ring opening when compound 6 is prepared from compound 7, which will produce isomers, which require column chromatography separation, complicated operation, and partial yield. Low

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