Reaction equation
[NH:1]([C:5]1[CH:6]=[C:7]([CH:12]=[CH:13][CH:14]=1)[C:8]([O:10][CH3:11])=[O:9])[C:2]([NH2:4])=[S:3].BrBr.C(OCC)C>ClC1C=CC=CC=1>[NH2:4][C:2]1[S:3][C:6]2[C:7]([C:8]([O:10][CH3:11])=[O:9])=[CH:12][CH:13]=[CH:14][C:5]=2[N:1]=1Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Procedure
8.4 g of methyl 3-thioureido-benzoate are suspended in 120 ml of chlorobenzene, 2.2 ml of bromine in 30 ml of chlorobenzene are added at 0° C. in the course of 1 hour, while stirring as thoroughly as possible, and the mixture is then stirred to room temperature. It is then kept at 70° C. for 4 hours and subsequently cooled, a little diethyl ether is added and the precipitate is filtered off, mixed thoroughly with 70 ml of aqueous sodium bicarbonate solution, filtered off again and washed with water. 7.7 g (88%) of crude product of melting point 231-2320° C. result. HPLC analysis shows a content of more than 83% of the pure title compound, in addition to 8-18% of isomeric methyl 2-amino-benzothiazole-5-carboxylate. Suspension in and brief heating at 70° C. with ethyl acetate, cooling to 30° C. and filtration give the pure title compound of melting point >250° C. If the reaction is carried out in acetic acid (instead of in chlorobenzene), the content of the undesired isomeric methyl 2-amino-benzothiazole-5-carboxylate is only about 5%.
Workup
- stirringis then stirred to room temperature
- temperaturesubsequently cooled
- filtrationthe precipitate is filtered off
- additionmixed thoroughly with 70 ml of aqueous sodium bicarbonate solution
- filtrationfiltered off again
- washwashed with water
- custom7.7 g (88%) of crude product of melting point 231-2320° C. result
Sources & evidence
- ORD record
- ord-eab5d479fd4f41c38e6aa7cc89486770
- Source dataset
- uspto-grants-2002_04
- Patent number
- US06380422B1
Linked notes
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