A photocatalytic synthesis method of C2 substituted 2h-benzothiazole hydroxyalkylated derivatives

A technology of benzothiazole hydroxyalkyl and synthesis method, which is applied in the field of photocatalytic synthesis of C2-substituted 2H-benzothiazole hydroxyalkylated derivatives, can solve the problems of residues, toxic metals, high price and the like, and achieves a catalytic system Simple, mild reaction conditions, and broad substrate effect

Active Publication Date: 2021-11-02
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The method has simple reaction steps and is carried out at room temperature, but the use of transition metal iridium as a catalyst has problems such as high price, certain toxicity and unavoidable metal residues.

Method used

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  • A photocatalytic synthesis method of C2 substituted 2h-benzothiazole hydroxyalkylated derivatives
  • A photocatalytic synthesis method of C2 substituted 2h-benzothiazole hydroxyalkylated derivatives
  • A photocatalytic synthesis method of C2 substituted 2h-benzothiazole hydroxyalkylated derivatives

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Example 1 Derivative Ia((R)n=H, R 1 =H,R 2 = methyl) synthesis

[0023] Weigh 2H-benzothiazole (0.3mmol, 40.6mg), ethanol (6.0mmol, 276.4mg), 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 20W 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 71%.

[0024] of the compound 1 H NMR and 13 C NMR analysis data are described below,

[0025] 1 H NMR (500MHz, CDCl 3 )δ7.96(d, J=8.0Hz, 1H), 7.86(d, J=8.0Hz, 1H), 7.45(dd, J=8.0, 7.0Hz, 1H), 7.36(t, J=8.0Hz, 1H), 5.25(q, J=6.5Hz, 1H), 3.81(br, 1...

Embodiment 2

[0026] Example 2 Derivative Ib((R)n=H, R 1 =H,R 2 = ethyl) synthesis

[0027]Weigh 2H-benzothiazole (0.3mmol, 40.6mg), n-propanol (6.0mmol, 360.6mg), Selectfluor (0.9mmol, 318.9mg) and trifluoroacetic acid (0.30mmol, 34.2mg) in a 25mL reaction tube , then add acetonitrile (65mmol, 2.7g), place it under the irradiation of 20W 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 1:1) to obtain a white solid, namely derivative Ib. Yield 60%.

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

[0029] 1 H NMR (500MHz, CDCl 3 )δ7.98(d,J=8.5Hz,1H),7.88(d,J=8.0Hz,1H),7.50–7.44(m,1H),7.41–7.35(m,1H),5.05(dd,J =7.5,5.0Hz,1H),3.70(br,1H),2.09(m,1H),2.01–1.93(m,1H),1.07(t,J=7.5Hz,3H). ...

Embodiment 3

[0030] Example 3 Derivatives Ic((R)n=H, R 1 = methyl, R 2 = methyl) synthesis

[0031] Weigh 2H-benzothiazole (0.3mmol, 40.6mg), isopropanol (6.0mmol, 360.6mg), Selectfluor (0.6mmol, 212.6mg) and trifluoroacetic acid (0.30mmol, 34.2mg) in a 25mL reaction tube , add acetonitrile (58mmol, 2.4g) again, place reaction under 20WLED blue light lamp, stir reaction at room temperature, TLC monitors, after about 16h, reaction finishes, and reaction solution is concentrated to remove solvent, and concentrated solution is separated through column chromatography (eluent (Petroleum ether-ethyl acetate mixed solvent with a volume ratio of 1:1) to obtain a white solid, namely the derivative Ic. Yield 85%.

[0032] of the compound 1 H NMR and 13 C NMR analysis data are described below,

[0033] 1 H NMR (500MHz, CDCl 3 )δ8.00(d, J=8.0Hz, 1H), 7.89(d, J=8.0Hz, 1H), 7.48(t, J=7.5Hz, 1H), 7.38(t, J=7.0Hz, 1H) ,3.35(br,1H),1.77(s,6H). 13 C NMR (125MHz, CDCl 3 )δ180.10, 153.05, 135.30, 1...

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Abstract

The invention discloses a photocatalytic synthesis method of C2-substituted 2H-benzothiazole hydroxyl alkylated derivatives. It comprises the steps of: mixing substituted 2H-benzothiazole shown in formula (II) with aliphatic alcohol shown in formula (III), adding oxidant Selectfluor, additive trifluoroacetic acid, solvent acetonitrile, under nitrogen protection and LED Carry out stirring reaction at normal temperature under the irradiation of blue light, after TLC monitors to the end of reaction, the reaction solution is separated and purified to obtain C2 substituted 2H-benzothiazole hydroxyalkylated derivatives as shown in formula (I); the invention provides a A new method for the synthesis of 2H-benzothiazole C2 hydroxyalkylated derivatives induced by visible light using Selectfluor as an oxidant, trifluoroacetic acid as an additive, and acetonitrile as a solvent. The method has a simple catalytic system, mild reaction conditions, and a wide range of substrates wide.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a photocatalytic synthesis method of C2 substituted 2H-benzothiazole hydroxyl alkylated derivatives. Background technique [0002] C2-substituted 2H-benzothiazole derivatives have good biological activity and high structural diversity, and have broad application prospects in the fields of pesticides and medicine. 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. And the structure of introducing hydroxyalkyl at the C2 position of 2H-benzothiazole also exists in various dru...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D277/64C07D277/68
CPCC07D277/64C07D277/68
Inventor 翁建全孔瑶蕾刘幸海谭成侠
Owner ZHEJIANG UNIV OF TECH
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