CS265783B1 - Preparation of 1-methyl-5-methylamino-6-aminouracil - Google Patents

Abstract

The present invention provides a process for the preparation of 1-methyl-5-methylamino-6-aminouracil by reaction of liquid anhydrous methylamine with 1-methyl-5-bromo-6-aminouracil at temperatures of -6 ° C to 80 ° C and methylamine molar ratios of: uracil = 4: 1 to 50: 1. The compound in question serves as an intermediate in the preparation of the bromo bromine.

Description

265783 2

The present invention relates to a process for the preparation of 1-methyl-5-methylamino-6-aminouracil of formula X 0/1, I-CH, NH, CH, which is an intermediate for theobromine production.

Preparations of a precursor compound of formula I from 1-methyl-5-bromo-6-aminouracil sample II have been described.

Br Ό I ‘NH 2 CH 3/11) by treatment with methylamine in pyridine (Jap. Pat. 7 411 389) or in aqueous methylamine (Polish Pat. No. 42,976).

According to the present invention, the subject compound of formula (I) is obtained from a bromo derivative of formula (II) by causing an excess of liquid anhydrous methylamine which acts both as a reagent and as a solvent. The reaction proceeds at temperatures from -6 ° C to 80 ° C in closed pressure vessels, an excess of methylamine to the bromo derivative of formula II is needed in a ratio of 4: 1 to 50: 1. The advantage of such a reaction is the high selectivity of the reaction caused by the anhydrous conversion of the process, as well as the excess of methylamine, which can be easily recycled after completion of the distillation reaction. Methylamine from the reaction mixture is distilled and liquefied with brine to allow the industrial reaction to proceed. In the following, the subject matter of the invention is illustrated by the following examples, without being limited thereto. EXAMPLE 1 4.4 g of 1-methyl-6-amino-5-bromouracil (0.02 M) are mixed with 25 ml of anhydrous methylamine and heated to 40 DEG C. in a closed pressure tube for 4 hours.

After heating, the reaction mixture was stirred for 6 hours. After completion of the reaction, the excess methylamine is evaporated by loosening the cap and 45 to 50 ml of ethanol are added to the residue and boiling for 10 minutes. After cooling, white crystalline 1-methyl-6-amino-5-methylaminouracil (2.8 g, 79.4%), mp 225-230 ° C, is suctioned off. Example 2

A mixture of 4.4 g of 1-methyl-6-amino-5-bromouracil (0.02 M) and 20 mL of anhydrous methylamine was stirred under a sealed apparatus at 20 ° C for 24 hours. Excess methylamine is evaporated, the solid residue is dissolved in 15 ml of water by addition of 1.5 to 2 ml of acetic acid. Charcoal is added, filtered and the clear solution is precipitated with aqueous ammonia. The precipitated 1-methyl-6-amino-5-methylamino-uracil is filtered off with suction and dried. Yield 2.91 g.

Claims (1)

EXAMPLE 3 10 g of 1-methyl-6-amino-5-bromouracil (0.045 M) and 30 ml of anhydrous methylamine were heated to 70 DEG C. for 4 hours in a sealed tube with stirring. After working up the crude reaction mixture after distilling off the methylamine with ethanol, 6.5 g of a white crystalline product (84%) were obtained, m.p. 225-230 ° C. Example 4 Analogously to Example 1, 0.4 g of potassium iodide was added to the reaction mixture to yield 2.8 g. Example 5 5 g of 1-methyl-6-amino-5-bromouracil and 15 ml anhydrous methylamine and 0.1 g CuCl 2 are heated at 40 ° C for 4 hours. Excess methylamine is evaporated, 50 ml of ethanol is added and filtered. 3.7 g of product are obtained. OBJECT OF THE INVENTION Preparation of 1-methyl-5-methylamino-6-aminouracil of Formula IO ch3 / 1/1-methyl-5-bromo-6-aminouracil of formula II And / or methylamine, characterized in that the reaction is carried out in an excess of liquid anhydrous methylamine with a methylamine molar ratio of the formula II = 4: 1 to 50: 1.