Acetonitrile → 3-Methylureido-1-(gamma-sulfopropyl)-5-pyrazolone

Into 30 ml of acetonitrile was dissolved 15.9 g of ethylβ-amino-β-ethoxy acrylate, and 6 g of methyl isocyanate was added thereto. The resulting mixture was allowed to stand at room temperature for two days. Into a mixed solution of 40 ml of glacial acetic acid and 20 ml of triethylamine there was dispersed 15.4 g of γ-hydrazinopropane sulfonic acid, and the above ester reaction solution was then added thereto and stirred while heating (95°-100° C.) on a water bath. In a short time, the solution became uniform and it was stirred as it was while heating (95°-100° C.) for 5 hours. The reaction solution was then concentrated under reduced pressure, and 50 ml of ethanol containing 35% by wt hydrogen chloride was then added to the resulting concentrated residue to thereby produce a uniform solution. This solution was allowed to stand in a refrigerator overnight and the crystals which precipitated were collected and recrystallized from methanol; thus, 14.8 g of crystals of the objective compound of a decomposition point of 186° C. was obtained.

1. additionwas added
2. additionwas then added
3. temperaturewhile heating (95°-100° C.) on a water bath
4. stirringwas stirred as it
5. temperaturewhile heating (95°-100° C.) for 5 hours
6. concentrationThe reaction solution was then concentrated under reduced pressure, and 50 ml of ethanol containing 35% by wt hydrogen chloride
7. additionwas then added to the resulting concentrated residue
8. customto thereby produce a uniform solution
9. customto stand in a refrigerator overnight
10. customthe crystals which precipitated
11. customwere collected
12. customrecrystallized from methanol

ORD record

ord-5ae147f62de241d8b01590ddb16f5901

Source dataset

uspto-grants-1980_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04188489