2-Benzothiazolamine,7-chloro-(9CI) synthesis

9synthesis methods

Product Name:2-Benzothiazolamine,7-chloro-(9CI)
CAS Number:20358-01-4
Molecular formula:C7H5ClN2S
Molecular Weight:184.65

4947-89-1

20358-00-3

20358-01-4

General procedure for the synthesis of 2-amino-5-chlorobenzothiazole and 7-chlorobenzo[d]thiazol-2-amine from 3-chlorobenzothiourea: 3-chlorobenzothiourea (105 mg, 0.56 mmol) was dissolved in 10 mL of acetic acid. Benzyltrimethylammonium tribromide (329 mg, 0.84 mmol) was added and the reaction mixture was stirred at room temperature for 14 hours. After completion of the reaction, the acetic acid was removed by distillation under reduced pressure. The residue was redissolved in 15 mL of dichloromethane (DCM) and 10 mL of 0.5 N aqueous sodium hydroxide was added. The aqueous phase was extracted with dichloromethane (2 x 15 mL). The organic layers were combined, filtered through a phase separator and concentrated under reduced pressure to remove the solvent. The crude product was purified by fast column chromatography using pentane-ethyl acetate (12:5) as eluent to afford the target product 2-amino-5-chlorobenzothiazole (61 mg, 59% yield) as a white solid. The structure of the product was analyzed by 1H NMR (500 MHz, CD3OD) δ 7.05 (dd, J = 8.4, 2.0 Hz, 1H), 7.35 (d, J = 2.0 Hz, 1H), 7.53 (d, J = 8.4 Hz, 1H); 13C NMR (125 MHz, CD3OD) δ 117.41, 121.45, 121.60 129.37, 131.55, 153.24, 170.04; Mass Spectrometry (ESI): m/z 185 [M + H]+ confirmed.

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20358-00-3 Synthesis

20358-00-3
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20358-01-4
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Yield: 59% ， 12%

Reaction Conditions:

with benzyltrimethylazanium tribroman-2-uide in acetic acid at 20; for 14 h;

Steps:

5-Chlorobenzothiazol-2-amine (15)
Thiourea 14 (105 mg, 0.56 mmol) was dissolved in 10 ml acetic acid. Benzyltrimethylammonium tribromide (329 mg, 0.84 mmol) was added and the reaction was stirred at rt for 14h. Acetic acid was removed in vacuo and the residue redissolved in 15 ml DCM. 10 ml 0.5 n aqueous NaOH was added and the aqueous phase was extracted with DCM (2 x 15 ml). The combined organic layers were filtered through a phase separator and the solvent was removed in vacuo. The crude product was purified by flash column chromatography with pentane-ethyl acetate (12:5) as eluent to yield 15 (61 mg, 59%) as a white solid: ¹H NMR (500 MHz, CD₃OD) 7.05 (dd, J=8.4, 2.0 Hz, 1H), 7.35 (d, 2.0 Hz, 1H), 7.53 (d, J=8.4 Hz, 1H); ¹³C NMR (125 MHz, CD₃OD) 117.41, 121.45, 121.60, 129.37, 131.55, 153.24, 170.04MS (ESI): m/z 185 [M+H]⁺.

References:

Karle, Michael;Knecht, Wolfgang;Xue, Yafeng [Bioorganic and Medicinal Chemistry Letters,2012,vol. 22,# 14,p. 4839 - 4843] Location in patent:supporting information; experimental part

4947-89-1
94 suppliers
$8.00/1g

20358-01-4
63 suppliers
$58.00/100mg

References