Water → 6-(3-Chloro-4-hydroxyphenyl)-4,5-dihydro-5-methyl-1,2,4-triazin-3(2H)-one

32.64 g of ethyl N-[2-(3-chloro-4-hydroxyphenyl)-1-methyl-2-oxoethyl]carbamate [prepared as described in Example 1(b)] and 75.20 g of 80% hydrazine hydrate (i.e. a grade of hydrazine hydrate containing 20% w/w water) were added to 240 ml of butanol, and the mixture was heated under reflux for 18 hours. The butanol used as the solvent was distilled off under reduced pressure, and then 10% w/v aqueous hydrochloric acid was added, and the mixture was extracted with ethyl acetate. The ethyl acetate layer was washed with a saturated aqueous solution of sodium chloride, dried and concentrated by evaporation under reduced pressure. The residue was collected by filtration, washed with ethyl acetate and dried, to give 14.71 g of the title compound as a yellow powder melting at 218°-222° C. (with decomposition). The filtrate was purified by column chromatography through silica gel eluted with a 10:1 by volume mixture of chloroform and methanol, to give a further 5.64 g of the title compound as a pale yellow powder.

1. temperaturethe mixture was heated
2. temperatureunder reflux for 18 hours
3. distillationwas distilled off under reduced pressure
4. additionwas added
5. extractionthe mixture was extracted with ethyl acetate
6. washThe ethyl acetate layer was washed with a saturated aqueous solution of sodium chloride
7. customdried
8. concentrationconcentrated by evaporation under reduced pressure
9. filtrationThe residue was collected by filtration
10. washwashed with ethyl acetate
11. customdried

ORD record

ord-48905f2dc5b5401dbd93d8af8bfeb535

Source dataset

uspto-grants-1990_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04898862