Ethyl Acetate → Methyl 2-aminobenzo[d]thiazole-7-carboxylate

HRID 964766Notes

Reaction equation

HRID 964766 reaction equation
[NH2:1][C:2]1[S:3][C:4]2[CH:10]=[CH:9][C:8](C(OC)=O)=[CH:7][C:5]=2[N:6]=1.[C:15]([O:18][CH2:19]C)(=[O:17])C>>[NH2:1][C:2]1[S:3][C:4]2[C:10]([C:15]([O:18][CH3:19])=[O:17])=[CH:9][CH:8]=[CH:7][C:5]=2[N:6]=1

Participants

3

Reactant 2

HCID 8857Ethyl AcetateHCID 17609388Methyl 2-amino-1,3-benzothiazole-5-carboxylate

Product 1

HCID 10910742Methyl 2-aminobenzo[d]thiazole-7-carboxylate

Conditions

Temperature
30 °C

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°-232° 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

  1. filtrationfiltration

Sources & evidence

ORD record
ord-ff475011cb784bce9c6cb87ac67a6c3f
Source dataset
uspto-grants-1998_06
Patent number
US05770758

Reaction notes

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