Hydrochloric Acid → 1-methyl-1,3,5-triazine-2,4(1h,3h)-dione

Temperature

60 °C

A reaction mixture consisting of 70.2 gm. (0.6 mole) of the 1-methylbiuret prepared in Part A above, 3.5 l. absolute ethanol, and 200 ml. benzene is heated to the reflux temperature with stirring in a 5-l., three-necked flask fitted with a reflux condenser, a stirrer, and thermometer. A top of the condenser is fitted with a nitrogen outlet, but no water is run through the condenser. After removing the nitrogen outlet, 200 ml. of the medium is allowed to distill through the condenser. The reaction mixture is then cooled to 60° C., before 28 gm. (1.2 mole) of sodium metal is added slowly over an interval of five (5) minutes. A white solid precipitates, but stirring is continued until all the sodium is dissolved. At this point, 104 gm. (1.4 mole) of ethyl formate is added in one portion and the reaction mixture is again heated to the reflux temperature (about 75° C.) and refluxed for three (3) hours. The reaction mixture is cooled to about 30° C. and hydrogen chloride gas is blown over the surface until an acid pH is attained. The reaction mixture is again heated at the reflux temperature for 15 minutes. The hot mixture is filtered through a diatomaceous earth filter and the filter is washed with hot ethanol. The filtrate and washings are concentrated to a volume of 200 to 300 ml. by removing medium by evaporation under reduced pressure. The concentrate is cooled to 5° C. and set aside at that temperature for several hours for crystallization. The crystals are collected on a filter and washed with cold ethanol. After, drying the crystals under reduced pressure there is obtained 69 gm. (90% yield) of 1-methyl-5-azauracil having a melting range from 200° to 205° C. A sample recrystallized three times from ethanol has a melting point of 213° to 214° C.

1. custom, three-necked flask fitted with a reflux condenser, a stirrer
2. customA top of the condenser is fitted with a nitrogen outlet
3. customAfter removing the nitrogen outlet, 200 ml
4. distillationto distill through the condenser
5. customA white solid precipitates
6. dissolutionis dissolved
7. temperaturethe reaction mixture is again heated to the reflux temperature (about 75° C.)
8. temperatureThe reaction mixture is cooled to about 30° C.
9. temperatureThe reaction mixture is again heated at the reflux temperature for 15 minutes
10. filtrationThe hot mixture is filtered through a diatomaceous earth
11. filtrationfilter
12. washthe filter is washed with hot ethanol
13. concentrationThe filtrate and washings are concentrated to a volume of 200 to 300 ml
14. customby removing medium
15. customby evaporation under reduced pressure
16. temperatureThe concentrate is cooled to 5° C.
17. customset aside at that temperature for several hours for crystallization
18. customThe crystals are collected on
19. filtrationa filter
20. washwashed with cold ethanol
21. customAfter, drying the crystals under reduced pressure
22. customthere is obtained 69 gm

ORD record

ord-eb48180c1b0f4dc88d90516849169873

Source dataset

uspto-grants-1980_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04239753