Photocatalytic synthesis method of C2 substituted 2H-benzothiazole benzylated derivative

A technology of benzothiazole benzyl and synthesis method is applied in the field of photocatalytic synthesis of C2-substituted 2H-benzothiazole benzyl derivatives, and can solve the problems of oxidant organic peroxides, such as inflammability and explosion, high reaction temperature and the like , to achieve the effect of low price, good reaction repeatability and simple catalytic system

Inactive Publication Date: 2020-11-27
ZHEJIANG UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this method has certain limitations, such as relatively high reaction

Method used

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  • Photocatalytic synthesis method of C2 substituted 2H-benzothiazole benzylated derivative
  • Photocatalytic synthesis method of C2 substituted 2H-benzothiazole benzylated derivative
  • Photocatalytic synthesis method of C2 substituted 2H-benzothiazole benzylated derivative

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Example 1 Synthesis of Derivative Ia (n=0)

[0022] Weigh 2 H -Benzothiazole (0.3 mmol, 40.6 mg), toluene 6.0 mmol, 552.8 mg), Selectfluor (0.9 mmol, 318.9 mg) and trifluoroacetic acid (0.30 mmol, 34.2 mg) in a 25 mL reaction tube, then added acetonitrile ( 58 mmol, 2.4 g), placed under the irradiation of 30 W LED blue light to react, stirred at room temperature, monitored by TLC, after about 16 h, the reaction was completed, the reaction solution was concentrated to remove the solvent, and the concentrated solution was separated by column chromatography (washing The solvent removal is petroleum ether-ethyl acetate mixed solvent with a volume ratio of 1:10) to obtain a white solid, i.e. derivative Ia. Yield 78%.

[0023] of the compound 1 H NMR and 13 C NMR analysis data are described below,

[0024] 1 H NMR (500 MHz, CDCl 3 ) δ 7.95 (d, J = 8.0 Hz, 1H), 7.71 (d, J = 8.0 Hz,1H), 7.46 (t, J = 7.5Hz, 1H), 7.29 – 7.21 (m, 6H), 4.39 (s, 2H). 13 C NMR (125MHz...

Embodiment 2

[0026] Example 2 Synthesis of derivative Ib (n=1, (R)n=p-methyl)

[0027] Weigh 2 H- Benzothiazole (0.3 mmol, 40.6 mg), p-xylene (6.0 mmol, 636.3 mg), Selectfluor (0.9 mmol, 318.9 mg) and trifluoroacetic acid (0.30 mmol, 34.2 mg) in a 25 mL reaction tube, and then Add acetonitrile (65 mmol, 2.7 g), react under the irradiation of 20 W LED blue light, stir the reaction at room temperature, monitor by TLC, the reaction ends after about 16 h, the reaction solution is concentrated to remove the solvent, and the concentrated solution is subjected to column chromatography Separation (eluent is a mixed solvent of petroleum ether-ethyl acetate with a volume ratio of 1:10) to obtain a white solid, namely derivative Ib. Yield 86%.

[0028] of the compound 1 H NMR and 13 C NMR analysis data are described below,

[0029] 1 H NMR (500 MHz, CDCl 3 ) δ 7.98 (d, J = 8.5 Hz, 1H), 7.74 (d, J = 8.0 Hz,1H), 7.42 (t, J = 7.5 Hz, 1H), 7.28 (t, J = 7.5 Hz, 1H), 7.23 (d, J = 7.5 Hz,2H...

Embodiment 3

[0031] Example 3 Synthesis of derivative Ic (n=2, (R)n=3, 5-dimethyl)

[0032] Weigh 2 H - Benzothiazole (0.3 mmol, 40.6 mg), mesitylene (4.5 mmol, 540.4 mg), Selectfluor (0.6 mmol, 212.6 mg) and trifluoroacetic acid (0.24 mmol, 27.4 mg) in a 25 mL reaction tube, and then Add acetonitrile (45 mmol, 1.9 g), place it under a 20 W LED blue light to react, stir the reaction at room temperature, monitor with TLC, after about 16 h, the reaction ends, the reaction solution is concentrated to remove the solvent, and the concentrated solution is separated by column chromatography (washing The solvent removal is petroleum ether-ethyl acetate mixed solvent with a volume ratio of 1:10) to obtain a white solid, namely the derivative Ic. The yield is 83%.

[0033] of the compound 1 H NMR and 13 C NMR analysis data are described below,

[0034] 1 H NMR (500 MHz, CDCl 3 ) δ 8.05 (d, J = 8.2 Hz, 1H), 7.83 (d, J = 8.0 Hz,1H), 7.39 (t, J = 8.0 Hz, 1H), 7.25 (t, J = 7.5 Hz, 1H), 6...

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Abstract

The invention discloses a photocatalytic synthesis method of a C2 substituted 2H-benzothiazole benzylated derivative. The photocatalytic synthesis method comprises the following steps of: mixing 2H-benzothiazole with substituted methyl benzene; adding an oxidizing agent Selectfluor, an additive trifluoroacetic acid and a solvent acetonitrile, carrying out a normal temperature stirring reaction under the protection of nitrogen and the irradiation of an LED blue light lamp, carrying out TLC monitoring until the reaction is finished, and carrying out separation and purification on the reaction liquid to obtain the C2 substituted 2H-benzothiazole benzylated derivative. The new method for synthesizing the C2 substituted 2H-benzothiazole benzylated derivative through visible light induction by taking Selectfluor as an oxidizing agent, trifluoroacetic acid as an additive and acetonitrile as a solvent is high in atom economy, simple in catalytic system, good in product yield, wide in substraterange and suitable for popularization and application.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, in particular to a C2-substituted 2 H - Photocatalytic synthesis of benzylated derivatives of benzothiazole. Background technique [0002] 2 replaced by C2 H -Benzothiazole derivatives are an important class of heterocyclic compounds, which widely exist in natural products and pharmaceutical molecules, because of their good anti-tumor (Eur. J. Med. Chem. 2013, 63, 702), anti- Cancer (Mini-Rev. Med. Chem. 2020, 1, 12), anti-inflammatory (J. Chem. Sci. 2012, 124, 609), insecticidal (J.Pharm. Res. 2013, 7, 439), bactericidal (Molecules, 1997, 2, 36), herbicidal (Bioorg. Med. Chem. Lett., 2016, 26, 1854), antiviral (Chin. J. Org. Chem., 2007, 27, 279) and other biological activities much attention. Part of C2 replaced by 2 H - Benzothiazole derivatives have been successfully developed as clinical drugs and commercial pesticides, clinical drugs such as pramipexole hydrochloride drug for...

Claims

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Application Information

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IPC IPC(8): C07D277/64
CPCC07D277/64
Inventor 翁建全孔瑶蕾葛存
Owner ZHEJIANG UNIV OF TECH
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