Sulfuric Acid → 1-Methyl-3-(4-carbamoyl-3-(dimethylamino)-5-isothiazolyl)urea
Reaction equation
[CH3:1][NH:2][C:3]([NH:5][C:6]1[S:10][N:9]=[C:8]([N:11]([CH3:13])[CH3:12])[C:7]=1[C:14]#[N:15])=[O:4].S(=O)(=O)(O)[OH:17]>>[CH3:1][NH:2][C:3]([NH:5][C:6]1[S:10][N:9]=[C:8]([N:11]([CH3:12])[CH3:13])[C:7]=1[C:14](=[O:17])[NH2:15])=[O:4]Participants
Procedure
A mixture of 11.2 g of 1-methyl-3-(4-cyano-3-(dimethylamino)-5-isothiazolyl)urea and 20 ml of concentrated sulfuric acid was heated at 85°-90° for 11/2 hours. The reaction mixture was poured into 300 ml of ice-water and the solid precipitate was collected by filtration. The solid was washed with water and a small amount of cold ethanol. The nmr spectrum of this solid (m.p. 243°, decomposes) indicated it to be the bisulfate salt of 1-methyl-3-(4-carbamoyl-3-(dimethylamino)-5-isothiazolyl)urea. The water-sulfuric acid filtrate was concentrated under reduced pressure, the concentrate was cooled and a solid precipitate was collected by filtration. This solid was combined with the bisulfate salt described above and was stirred with a saturated solution of sodium bicarbonate. A new solid was collected by filtration and purified by recrystallization from ethanol to give 9.2 g of 1-methyl-3-(4-carbamoyl-3-(dimethylamino)-5-isothiazolyl)urea; m.p. 221°. The nmr spectrum was consistent with the assigned structure.
Workup
- temperaturewas heated at 85°-90° for 11/2 hours
- filtrationthe solid precipitate was collected by filtration
- washThe solid was washed with water
- concentrationThe water-sulfuric acid filtrate was concentrated under reduced pressure
- temperaturethe concentrate was cooled
- filtrationa solid precipitate was collected by filtration
- filtrationA new solid was collected by filtration
- custompurified by recrystallization from ethanol
Sources & evidence
- ORD record
- ord-b3e717ec869b447386992252c00bcf63
- Source dataset
- uspto-grants-1978_02
- Patent number
- US04075001
Reaction notes
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