Mild photocatalytic synthesis method of C2 ether substituted 2H-benzothiazole derivative

A benzothiazole and synthesis method technology, applied in the field of photocatalytic synthesis of C2 ether substituted 2H-benzothiazole derivatives, can solve the problems of complex reaction catalytic system, low substrate applicability, long reaction time, etc.

Inactive Publication Date: 2020-06-09
ZHEJIANG UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This type of reaction effectively synthesizes C2 ether-substituted benzothiazole derivatives, but the former takes too long to rea

Method used

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  • Mild photocatalytic synthesis method of C2 ether substituted 2H-benzothiazole derivative
  • Mild photocatalytic synthesis method of C2 ether substituted 2H-benzothiazole derivative
  • Mild photocatalytic synthesis method of C2 ether substituted 2H-benzothiazole derivative

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Example 1 derivative Ia (R 1 = Ethyl, R 2 = ethyl) synthesis

[0020] Weigh 2H-benzothiazole (0.3mmol, 40.6mg), diethyl ether (6.0mmol, 444.72mg), Selectfluor (0.9mmol, 318.9mg) and trifluoroacetic acid (0.30mmol, 34.2mg) in a 25mL reaction tube, and then Add acetonitrile (58mmol, 2.4g), place it under the irradiation of a 30W LED blue light to react, stir the reaction at room temperature, and monitor it by TLC. After about 16h, the reaction ends, the reaction solution is concentrated to remove the solvent, and the concentrate is separated by column chromatography (washing The solvent removal is petroleum ether-ethyl acetate mixed solvent with a volume ratio of 1:1) to obtain a yellow solid, namely the derivative Ia. Yield 70%.

[0021] of the compound 1 H NMR and HRMS (ESI) analysis data are as follows,

[0022] 1 H NMR (500MHz, CDCl 3 )δ8.00(d,J=8.5Hz,1H),7.91(d,J=8.0Hz,1H),7.50–7.46(m,1H),7.39(td,J=8.5,1.5Hz,1H), 4.87(q, J=6.5Hz, 1H), 3.66–3.61(m, 2H), 1.66(d...

Embodiment 2

[0024] Embodiment 2 Derivatives Ib (R 1 = n-propyl, R 2 = n-propyl) synthesis

[0025] Weigh 2H-benzothiazole (0.3mmol, 40.6mg), n-propyl ether (6.0mmol, 613.02mg), Selectfluor (0.9mmol, 318.9mg) and trifluoroacetic acid (0.30mmol, 34.2mg) in a 25mL reaction tube , then add acetonitrile (75mmol, 3.1g), place it under the irradiation of 30W LED blue light to react, stir the reaction at room temperature, TLC monitoring, after about 18h, the reaction ends, the reaction solution is concentrated to remove the solvent, and the concentrate is separated by column chromatography (The eluent is a mixed solvent of petroleum ether-ethyl acetate with a volume ratio of 4:1) to obtain a yellow liquid, namely the derivative Ib. Yield 65%.

[0026] of the compound 1 H NMR and HRMS (ESI) analysis data are as follows,

[0027] 1 H NMR (500MHz, CDCl 3 )δ8.00(s,2H),7.91(s,2H),7.43(d,J=4.8Hz,4H),4.48(s,2H),3.35–3.31(m,4H),1.82(s,2H ),1.76(s,2H),1.53–1.49(m,3H),1.04–1.00(m,6H),0.99–0.95(m,6H...

Embodiment 3

[0029] Example 3 Derivatives Ic (R 1 = isopropyl, R 2 = isopropyl) synthesis

[0030] Weigh 2H-benzothiazole (0.3mmol, 40.6mg), isopropyl ether (4.5mmol, 459.765mg), Selectfluor (0.6mmol, 212.6mg) and trifluoroacetic acid (0.24mmol, 27.3mg) in a 25mL reaction tube , add acetonitrile (58mmol, 2.4g) again, place reaction under 20W LED blue light lamp, stir reaction at room temperature, TLC monitors, after about 20h, reaction ends, and reaction solution is concentrated to remove solvent, and concentrated solution is separated through column chromatography (elution The solvent is petroleum ether-ethyl acetate mixed solvent with a volume ratio of 5:1) to obtain a yellow liquid, namely the derivative Ic. Yield 68%.

[0031] of the compound 1 H NMR and HRMS (ESI) analysis data are as follows,

[0032] 1 H NMR (500MHz, CDCl 3 )δ8.01(d,J=8.0Hz,1H),7.90(d,J=8.0Hz,1H),7.49–7.45(m,1H),7.40–7.36(m,1H),3.88(dt,J =12.0,6.0Hz,1H),1.75(s,6H),1.20(d,J=6.0Hz,6H).

[0033] HRMS (ESI) calcd...

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Abstract

The invention discloses a mild photocatalytic synthesis method of a C2 ether substituted 2H-benzothiazole derivative. The preparation method comprises the following steps: mixing 2H-benzothiazole shown as a formula (II) with ether shown as a formula (III); adding an oxidizing agent Selectfluor, an additive trifluoroacetic acid and a solvent acetonitrile, carrying out a normal temperature stirringreaction 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 thereaction liquid to obtain the C2 ether substituted 2H-benzothiazole derivative represented by the formula (I). The invention provides a new method for synthesizing the C2 ether substituted 2H-benzothiazole derivative through visible light induction by taking Selectfluor as an oxidizing agent, trifluoroacetic acid as an additive and acetonitrile as a solvent, and the method has the advantages of simple catalytic system, mild reaction conditions, wide substrate range and the like.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a mild C2 ether-substituted photocatalytic synthesis method of 2H-benzothiazole derivatives. Background technique [0002] C2-substituted 2H-benzothiazole derivatives have broad-spectrum biological activities and high structural diversity, and have broad application prospects in agriculture, medicine and other fields. For example, in the field of pesticides, there are insecticidal (Pharmazie, 2003, 58, 527), 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; in the field of medicine, it has antibacterial (Eur.J.Med.Chem.,2010,45,1323), antitumor (Brit.J.Cancer,88,470), anti Cancer (Eur.J.Med.Chem., 54,447) and other biological activities. Among them, the synthesis of C2 ether substituted 2H-benzothiazole derivatives has also received more and ...

Claims

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Application Information

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IPC IPC(8): C07D275/04
CPCC07D275/04
Inventor 翁建全孔瑶蕾谭成侠刘幸海
Owner ZHEJIANG UNIV OF TECH
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