Methyl isothiocyanate → 4-Methyl-2-(methylamino)-1,3-benzothiazole-5-carboxylic acid
Reaction equation
[NH2:1][C:2]1[C:3]([CH3:11])=[C:4]([CH:8]=[CH:9][CH:10]=1)[C:5]([OH:7])=[O:6].[CH3:12][N:13]=[C:14]=[S:15].BrBr>C(O)(=O)C>[CH3:12][NH:13][C:14]1[S:15][C:10]2[CH:9]=[CH:8][C:4]([C:5]([OH:7])=[O:6])=[C:3]([CH3:11])[C:2]=2[N:1]=1Participants
5
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 100 °C
Procedure
99 g of 3-amino-2-methylbenzoic acid (0.655 mol) were initially charged in 500 ml of acetic acid and, at 80° C,. admixed with 51 g of methyl isothiocyanate (7 mol) in 100 ml of acetic acid. After 2 h, 106 g of bromine (0.66 mol) in 20 ml of acetic acid were added dropwise at 50° C. The mixture was subsequently heated at about 100° C. for 2 h and, after the reaction had ended, allowed to cool. The precipitate was filtered off, the filtrate was concentrated to about 50 ml and the remaining filtrate and the precipitate were added to water. The aqueous phase was adjusted to pH 5 and the precipitate was filtered off at 8° C. It was subsequently washed with water and dried. Yield: 66 g (42%).
Workup
- temperatureto cool
- filtrationThe precipitate was filtered off
- concentrationthe filtrate was concentrated to about 50 ml
- additionthe remaining filtrate and the precipitate were added to water
- filtrationthe precipitate was filtered off at 8° C
- washIt was subsequently washed with water
- customdried
Sources & evidence
- ORD record
- ord-01832ae01f6b43ccbfa4faece788c228
- Source dataset
- uspto-grants-2003_04
- Patent number
- US06541423B1
Reaction notes
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