Diethyl Ether → Methyl 2-aminobenzo[d]thiazole-7-carboxylate

HRID 2301016Notes

Reaction equation

HRID 2301016 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]=1

Participants

5

Reactant 3

HCID 3283Diethyl EtherHCID 24408BromineHCID 726316Methyl 3-thioureidobenzoate

Product 1

HCID 10910742Methyl 2-aminobenzo[d]thiazole-7-carboxylateYield 83%

Reagents, catalysts & solvents 1

HCID 7964ChlorobenzeneSolvent2×

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.

Workup

  1. stirringis then stirred to room temperature
  2. temperaturesubsequently cooled
  3. filtrationthe precipitate is filtered off
  4. additionmixed thoroughly with 70 ml of aqueous sodium bicarbonate solution
  5. filtrationfiltered off again
  6. washwashed with water
  7. custom7.7 g (88%) of crude product of melting point 231-232° C. result

Sources & evidence

ORD record
ord-e2016b5352bf46d481f3f9639189fd7f
Source dataset
uspto-grants-2002_12
Patent number
US06498265B2

Reaction notes

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