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Preparation method for cytosine

A technique of cytosine and dropwise addition, applied in the direction of organic chemistry and the like, can solve problems such as difficult operation and severe reaction, and achieve the effects of low cost, high yield, and cheap and easy-to-obtain raw materials.

Active Publication Date: 2012-12-12
SHANGYU HUALUN CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method uses thiourea as a raw material and requires the use of hydrogen peroxide, which has a violent reaction and is not easy to operate.

Method used

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  • Preparation method for cytosine
  • Preparation method for cytosine
  • Preparation method for cytosine

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Experimental program
Comparison scheme
Effect test

Embodiment 13

[0037] The preparation of embodiment 13,3-diethoxypropionitrile

[0038] (1) Add 550g (5.97mol) of toluene, 300g (4.05mol) of ethyl formate, 53g (1.29mol) of acetonitrile and 85g (1.25mol) of sodium ethylate into the condensation kettle. After nitrogen replacement, heat to 50°C for condensation reaction for 40h. After the reaction, the temperature was lowered to (31±3)°C to obtain the condensation reaction product.

[0039] (2) Add 500 g of toluene and 200 g of methanol hydrochloride to the acidification kettle in advance (the mass ratio of hydrochloric acid to methanol is 25:75), press the condensation reaction product into the acidification kettle, and the acidification temperature is 18°C. After the acidification was completed, 85 g of sodium hydroxide was added and stirred for 0.5 h to obtain an acidified solution. Suction filter the acidified solution into the concentration kettle. Control the temperature of the concentration tank to rise slowly to a temperature of 65°...

Embodiment 2

[0040] The preparation of embodiment 2 cytosine

[0041] Add 85 g (1.25 mol) of sodium ethylate, 500 g (4.71 mol) of xylene and 111 g (1.85 mol) of urea into the reaction kettle. The reaction kettle was heated to 95°C and stirred for 0.5h. 147.3 g (1.03 mol) of 3,3-diethoxypropionitrile prepared in Example 1 was added dropwise, the temperature was controlled at 100° C., the dropwise addition was completed, and the reaction was refluxed for 8 h. After the reaction was completed and concentrated to dryness, 1200 g of distilled water was added to dissolve the concentrate, and the mixture was allowed to stand to separate layers. The aqueous layer was added dropwise with 5 mol / L hydrochloric acid aqueous solution (0.62 mol hydrochloric acid), stirred for 30 min, and then adjusted to pH=7.0 with aqueous sodium hydroxide solution. Cooled to 0 ° C crystallization 8h. Centrifugation yielded 118 g of crude product.

[0042]Add 1500g of water and 20g of activated carbon into the refi...

Embodiment 3

[0046] The preparation of embodiment 3 cytosine

[0047] Add 85 g (1.25 mol) of sodium ethylate, 550 g (5.18 mol) of xylene and 96 g (1.50 mol) of urea into the reaction kettle. The reaction kettle was heated to 90°C and stirred for 0.3h. 143 g (1.00 mol) of 3,3-diethoxypropionitrile was added dropwise, the temperature was controlled at 105° C., and the reaction was refluxed for 10 h after the dropwise addition was completed. After the reaction was completed and concentrated to dryness, 1200 g of distilled water was added to dissolve the concentrate, and the mixture was allowed to stand to separate layers. Concentrated 5 mol / L hydrochloric acid aqueous solution (0.8 mol hydrochloric acid) was added dropwise to the aqueous layer, stirred for 30 min, and then adjusted to pH=7.5 with aqueous sodium hydroxide solution. Cooled to -5 ° C crystallization 8h. Centrifugation yielded 115 g of crude product.

[0048] Add 1500g of water and 10g of activated carbon into the refining ke...

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Abstract

The invention discloses a preparation method for cytosine. The preparation method comprises the following steps of: (1) mixing sodium ethoxide, dimethylbenzene, and carbamide, stirring the mixture at a temperature of 85 DEG C to 95 DEG C for 0.3-0.5 hours, dropping 3,3-diethoxy propionitrile, controlling the temperature between 100 DEG C and 105 DEG C, after finishing dropping, back-flow reacting for 8-10 hours, concentrating the mixture to be dried after finishing the reaction, adding distilled water to dissolve condensate, standing for stratification, dropping hydrochloric acid on a water layer and uniformly mixing, adjusting a pH value to equal to 7.0-7.5, cooling, crystallizing and centrifuging to obtain a crude product; and (2) adding the crude product in water and activated carbon, decoloring at the temperature of 70 DEG C to 80 DEG C, filtering and removing the activated carbon, cooling and crystallizing filter liquid, centrifuging to obtain a wet end product, and drying to obtain the cytosine. According to the preparation method, a catalyst difficult to obtain is prevented from using, the adopted raw materials are basic raw materials, the raw materials are cheap and easy to obtain, a subsequent treatment is simple, the cost is low, the yield is high, and the preparation method is suitable for the industrial production.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a preparation method of cytosine. Background technique [0002] Cytosine, also known as: 2-carbonyl-4-aminopyrimidine, CAS: 71-30-7, molecular formula: C 4 h 5 N 3 O, molecular mass: 111.10, melting point: 320-325°C. Cytosine is one of the four basic bases that make up DNA. It is also an important intermediate in fine chemicals, pesticides and medicine. Especially in the field of medicine, it is mainly used to synthesize anti-AIDS drugs, anti-hepatitis B drug lamivudine, and anti-cancer drugs. Gemcitabine, Enoxitabine, and 5-fluorocytosine are widely used. Cytosine has the following structural formula: [0003] [0004] The traditional preparation method of cytosine is: synthesized from dimercaptouracil, concentrated ammonia water and chloroacetic acid as raw materials. Among them, chloroacetic acid is a highly toxic compound, concentrated ammonia water is a strong corr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D239/47
Inventor 葛永明周艳波陈大祥唐伟银
Owner SHANGYU HUALUN CHEM
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