SU397004A1 - Method of obtaining 5-fluor-6-acetoxidihydrouracil - Google Patents

Description

(54) METHOD FOR OBTAINING 5-FLUOR-6 OF CETOXIDIHYDROURAZIL

one

The invention relates to a new method for the preparation of 5-4) Thor - 6-acetoxydihydiarouracil, which in its first form was obtained for the first time and may have potential physiological activity, being

the same time, the starting product for the synthesis of 5-fluorouracil.

An attempt has been described to synthesize b-fluoro-6-acetoxy and dihydrouradyl by catalytic hydrogenation of 5-bromo-5-fluoro-6-acetoxy dihydrouracil. However, under the conditions of hydrogenation, a mixture of 5ii TOp-6-ue- is formed. toksidigitrizuradila and B toruracil.

In order to increase yield and purity

target product uracil in ice

Acetic acid (4-8 g of uracil in 100 ml of acetic acid) at 15-25 C is treated with elemental fluorine diluted in a ratio of 1: 2-3 with an inert gas. The method of obtaining 5-4tor-6-acetoxy-dihydrouracil was implemented in an isothermal reactor with a circulation pipe made of stainless steel 1X18H9T with a capacity of 0.5 l under the hydrodynamic regime T e 40,000.

PRI me R. 300 ml of glacial acetic acid and 21.6 g of uracil are loaded into the reactor. In the intensive hydrodynamic mode (TR e 4OOOO) and the suspension is fed a gas mixture of fluorine mixture (1: 2.14) at a rate of 27.5 l / h until fluorine appears in the exhaust gases, then at a rate of 3.4 l / h until it disappears uracil in the reaction mixture. Temperature mode of reaction is 20-25 C. The method of controlling uracil in the reaction mixture is paper chromatography (system: ethyl acetate - 90% formic acid water in ratios 65: 5: 5, paper TiPtnakTM -11, for uracil 1. 0.300, 33) .

The total reaction time is no more than 1.5 hours. The resulting 5-fluoro-6-acetoxydihydrourales are isolated by filtration of the suspension of the reaction mixture, washed with ether, dried under a vacuum of 20 ° C. 28.6 g of the expected product are obtained, which constitutes 78% of the theoretical value. T. pl. 172-175 C with thermal decomposition to 5-fluorouracil. IR spectrum (nujols.cm): 3275.3230 (flat), 3150 (width NN) 1758, 1728 (C-0 ether and cycle), 1475, 137O (.), 1248, 1235 (C-0-C ether “Pa), 1136, 1080, 1032, 944. Paper chromatography: for uracil V 0.82-0.85; from utema: ethyl acetate 90% formic acid – water in a ratio x 65: 5: 5, paper Ti ft ha k TN 11. Elementary analysis. Found,% C 38.6 H 3.9; N 15.0, ". , 7. . . 37.9; H 3.7; N 14; 7 Calculated, G. The formula is in 1. Method of preparing 5..or - b-acetoles "digitsrouracil, characterized in that, in order to increase the yield and purity of the target product, uracil in glacial acetic acid is treated with el; with fluorine in an inert gas atmosphere followed by separation of the target product by known methods, 2. Method according to claim 1, about tl and h and with the fact that the process is carried out under the hydrodynamic regime of He 400OO and the concentration of uracil 4th in 100 tons of acetic acid.