Reaction #63700

Reaction equation

water

1-[2,4-dichloro-5-(1-methylethoxy)phenyl]-3,3-dimethyl-1,2,4-triazolidin-5-one

pyruvic acid

pyruvic acid

→

2-[2,4-dichloro-5-(1-methylethoxy)phenyl]-6-methyl-1,2,4-triazine-3,5(2H,4H)-dione

Yield 58.6%

Solvents

p-dioxane

Conditions

Workup

1. 1
   TemperatureThe mixture was heated at 90° C. for three hours
2. 2
   ExtractionThe mixture was extracted with ethyl acetate
3. 3
   Otherthe solvent was evaporated from the
4. 4
   Extractionextract under reduced pressure
5. 5
   Otherto give an oil
6. 6
   OtherThe oil was purified by thin-layer preparative chromatography on silica gel
7. 7
   Washeluting with ethyl acetate:heptane (1:1)
8. 8
   ExtractionExtraction of the appropriate bands

Procedure

To a stirred mixture of 1.0 g (0.0031 mole) of 1-[2,4-dichloro-5-(1-methylethoxy)phenyl]-3,3-dimethyl-1,2,4-triazolidin-5-one in 10 mL of p-dioxane was added 0.29 g (0.0031 mole) of pyruvic acid and one drop of concentrated sulfuric acid. The mixture was stirred at room temperature for one hour, then an additional 0.25 g (0.0029 mole) of pyruvic acid was added. The mixture was heated at 90° C. for three hours, then poured into water. The mixture was extracted with ethyl acetate, and the solvent was evaporated from the extract under reduced pressure to give an oil. The oil was purified by thin-layer preparative chromatography on silica gel, eluting with ethyl acetate:heptane (1:1). Extraction of the appropriate bands gave 0.6 g of 2-[2,4-dichloro-5-(1-methylethoxy)phenyl]-6-methyl-1,2,4-triazine-3,5(2H,4H)-dione as a solid (mp 163°-164° C.), Compound 10 in the tables.

Source