Detailed Description
Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.
It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.
It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The specification and examples are exemplary only.
As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.
The "parts" in the present invention are all parts by mass unless otherwise specified.
Example 1
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) benzenesulfonate (compound No. A)1) The method comprises the following steps:
(1) ethyl glycolate (0.05mol,1eq) was added to a 250mL three-necked flask at room temperature, and 100mL of absolute ethanol was added to the round-bottomed flask, followed by stirring at room temperature. Then, 80% hydrazine hydrate (0.1mol,2eq) was slowly added to the round-bottom flask with stirring at room temperature, and then heated to reflux. After the reaction is carried out for 12 hours, the reaction is stopped, the temperature is reduced by cooling, and the white intermediate product 2-hydroxyacetylhydrazine is separated out. The yield was 90%.
(2) To a 250mL three-necked round-bottomed flask, the intermediate 2-hydroxyacetylhydrazine (0.01mol,1eq) obtained in the previous step, potassium hydroxide (0.012mol,1.2eq) and 100mL of absolute ethanol were added in this order, followed by stirring and mixing. Then, after slowly adding carbon disulfide (0.012mol,1.2eq) under stirring at room temperature, the mixture was reacted at room temperature for 1 hour, then heated to 78 ℃ for reflux reaction for 6 hours, the solvent anhydrous ethanol was removed under reduced pressure on a rotary evaporator, the sample was stirred with silica gel, and the intermediate product 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol was obtained in a yield of 70% by column chromatography.
(3) In a 50mL single-neck flask, 20 mL of tetrahydrofuran as a solvent was added, followed by addition of the intermediate 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol obtained in the previous step (0.01mmol,1eq) and potassium hydroxide (0.012mmol,1.2eq), followed by stirring for dissolution, and then iodomethane (0.012mmol,1.2eq) was slowly added dropwise, followed by reaction with stirring at room temperature for 30 min. Judging that the reaction is finished by thin layer chromatography, removing the solvent under reduced pressure, mixing the sample with silica gel, and purifying by silica gel column chromatography to obtain an intermediate product, namely 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether, with the yield of 75%.
(4) To a 25mL round bottom flask was added intermediate 3(0.001mol,1eq) from the previous step at room temperatureAnd tetrahydrofuran (10mL) as a solvent, and after sufficiently dissolving the compound by stirring, sodium hydride (0.001mol,1eq) was slowly added. Stirring for 10min, slowly adding benzenesulfonyl chloride (0.0012mol,1.2eq) dropwise, reacting for 20min, tracking reaction progress by thin layer chromatography, filtering, and recrystallizing to obtain target compound A1The yield was 80%.
Example 2
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-fluorobenzenesulfonate (compound No. A)2) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 87% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 2 hours, and then heated to 78 ℃ under reflux for 5 hours, giving a yield of 65%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 60min, giving a yield of 70%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-fluorobenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 15min, and 4-fluorobenzenesulfonyl chloride was used as a starting material, the yield was 86%.
Example 3
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-chlorobenzenesulfonate (compound No. A)3) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 85% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1.5 hours, and then heated to 78 ℃ for reflux reaction for 5.5 hours, giving a yield of 68%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 50min, giving a yield of 80%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-chlorobenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 30min, and 4-chlorobenzenesulfonyl chloride was used as a starting material in a yield of 76%.
Example 4
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-bromobenzenesulfonate (compound No. A)4) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 88% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 2 hours, and then heated to 78 ℃ under reflux for 6 hours, giving a yield of 70%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 55min, and the yield was 78%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-bromobenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 25min, and 4-bromobenzenesulfonyl chloride was used as a starting material in 55% yield.
Example 5
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-methoxybenzenesulfonate (compound No. A)5) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 90% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1 hour, and then heated to 78 ℃ under reflux for 5 hours, giving a yield of 68%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 30min, giving a yield of 70%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-methoxybenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 15min, and 4-methoxybenzenesulfonyl chloride was used as a starting material in 66% yield.
Example 6
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-nitrobenzenesulfonate (compound No. A)6) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 85% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1.3 hours, and then heated to 78 ℃ for reflux reaction for 5.5 hours, giving a yield of 70%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 35min, and the yield was 73%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-nitrobenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 30min, and 4-nitrobenzenesulfonyl chloride was used as a starting material in a yield of 74%.
Example 7
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) -4- (trifluoromethyl) benzenesulfonate (compound No. A)7) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 90% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1.8 hours, and then heated to 78 ℃ for reflux reaction for 6 hours, giving a yield of 60%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 60min, giving a yield of 80%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) -4- (trifluoromethyl) benzenesulfonate: the procedure is as in example 1, step (4), except that the reaction is terminated after 20min, starting from 4- (trifluoromethyl) -benzenesulfonyl chloride in 84% yield.
Example 8
(5- (methylthio) -1,3, 4-oxadiazol-2-yl) -2-fluorobenzenesulfonic acid methyl esterSynthesis of (Compound No. A)8) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: as in step (1) of example 1, the yield was 88%
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 2 hours, and then heated to 78 ℃ for reflux reaction for 5.5 hours, giving a yield of 65%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 40min, and the yield was 75%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) -2-fluorobenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 30min, and 2-fluorobenzenesulfonyl chloride was used as a starting material in a yield of 82%.
Example 9
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) -3-fluorobenzenesulfonate (compound No. A)9) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 85% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1 hour, and then heated to 78 ℃ for reflux reaction for 6 hours, giving a yield of 68%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 45min, giving a yield of 80%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) -3-fluorobenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 25min, and 3-fluorobenzenesulfonyl chloride was used as a starting material in a yield of 72%.
Example 10
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 3-chlorobenzenesulfonate (compound No. A)10) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 88% as in the step (1) of example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 2 hours, and then heated to 78 ℃ for reflux reaction for 5.5 hours, giving a yield of 70%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 50min, and the yield was 75%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) -3-chlorobenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 15min, and 3-chlorobenzenesulfonyl chloride was used as a starting material in a yield of 81%.
Example 11
Synthesis of methyl (5- (ethylsulfanyl) -1,3, 4-oxadiazol-2-yl) 4-fluorobenzenesulfonate (compound No. A)11) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 90% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1.2 hours, and then heated to 78 ℃ for reflux reaction for 6 hours, giving a yield of 65%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-ethylsulfide: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 30min and that iodoethane was used as a starting material in a yield of 70%.
(4) Synthesis of methyl (5- (ethylsulfanyl) -1,3, 4-oxadiazol-2-yl) -4-fluorobenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 20min, and 4-fluorobenzenesulfonyl chloride was used as a starting material in 80% yield.
Example 12
Synthesis of methyl (5- (ethylsulfanyl) -1,3, 4-oxadiazol-2-yl) 4-chlorobenzenesulfonate (compound No. A)12) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 85% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1 hour, and then heated to 78 ℃ for reflux reaction for 5 hours, giving a yield of 67%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-ethylsulfide: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 50min and that iodoethane was used as a starting material in a yield of 70%.
(4) Synthesis of methyl (5- (ethylsulfanyl) -1,3, 4-oxadiazol-2-yl) -4-chlorobenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 25min, and 4-chlorobenzenesulfonyl chloride was used as a starting material in a yield of 78%.
Example 13
Synthesis of methyl (5- (ethylsulfanyl) -1,3, 4-oxadiazol-2-yl) 4-bromobenzenesulfonate (compound No. A)13) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 88% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1.5 hours, and then heated to 78 ℃ for reflux reaction for 5.5 hours, giving a yield of 70%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 55min and that iodoethane was used as a starting material in a yield of 75%.
(4) Synthesis of ethyl (5- (ethylsulfanyl) -1,3, 4-oxadiazol-2-yl) -4-bromobenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 30min, and 4-bromobenzenesulfonyl chloride was used as a starting material in a yield of 72%.
Example 14
Synthesis of methyl (5- (2-fluoroethylthio) -1,3, 4-oxadiazol-2-yl) 4-fluorobenzenesulfonate (compound No. A)14) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 88% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1.5 hours, and then heated to 78 ℃ for reflux reaction for 5.5 hours, giving a yield of 70%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-fluoroethylene sulfide: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 55min and 1-fluoro-2-iodoethane was used as a starting material in a yield of 75%.
(4) Synthesis of methyl (5- (2-fluoroethylthio) -1,3, 4-oxadiazol-2-yl) -4-fluorobenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 25min, and 4-fluorobenzenesulfonyl chloride was used as a starting material, the yield was 62%.
Example 15
Synthesis of methyl (5- (2-fluoroethylthio) -1,3, 4-oxadiazol-2-yl) 4-chlorobenzenesulfonate (compound No. A)15) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 90% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 2 hours, and then heated to 78 ℃ under reflux for 6 hours, giving a yield of 68%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-fluoroethylene sulfide: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 45min and 1-fluoro-2-iodoethane was used as a starting material in a yield of 78%.
(4) Synthesis of methyl (5- (2-fluoroethylthio) -1,3, 4-oxadiazol-2-yl) -4-chlorobenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 30min, and 4-chlorobenzenesulfonyl chloride was used as a starting material in a yield of 80%.
Example 16
Synthesis of methyl (5- (2-fluoroethylthio) -1,3, 4-oxadiazol-2-yl) 4-bromobenzenesulfonate (compound No. A)16) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 90% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 2 hours, and then heated to 78 ℃ under reflux for 6 hours, giving a yield of 68%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-fluoroethylene sulfide: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 45min and 1-fluoro-2-iodoethane was used as a starting material in a yield of 80%.
(4) Synthesis of methyl (5- (2-fluoroethylthio) -1,3, 4-oxadiazol-2-yl) -4-bromobenzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 28min, and 4-bromobenzenesulfonyl chloride was used as a starting material in 80% yield.
Example 17
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) dimethylaminosulfonate (compound number A)17) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 90% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 2 hours, and then heated to 78 ℃ under reflux for 6 hours, giving a yield of 68%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 45min, giving a yield of 80%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) dimethylaminosulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 30min, and dimethylaminosulfonyl chloride was used as a starting material in a yield of 80%.
Example 18
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 2- (trifluoromethyl) benzenesulfonate (compound No. A)18) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 87% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1.5 hours, and then heated to 78 ℃ for reflux reaction for 5.5 hours, giving a yield of 70%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 35min, giving a yield of 80%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 2- (trifluoromethyl) benzenesulfonate: the procedure was as in (4) in example 1, except that the reaction was terminated after 28min, and 2-trifluoromethylbenzenesulfonyl chloride was used as a starting material in a yield of 64%.
Example 19
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) benzoate (Compound No. B)1) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 87% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1.5 hours, and then heated to 78 ℃ for reflux reaction for 6 hours, giving a yield of 70%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 58min, giving a yield of 74%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) benzoate: the procedure was as in (4) in example 1, except that the reaction was terminated after 25min, and benzoyl chloride was used as a starting material in a yield of 77%.
Example 20
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-fluorobenzoate (Compound No. B)2) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 90% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 2 hours, and then heated to 78 ℃ for reflux reaction for 5.5 hours, giving a yield of 68%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 37min, giving a yield of 72%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-fluorobenzoate: the procedure was as in (4) in example 1, except that the reaction was terminated after 18min, and 4-fluorobenzoyl chloride was used as a starting material in a yield of 75%.
Example 21
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-chlorobenzoate (Compound No. B)3) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 87% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1.6 hours, and then heated to 78 ℃ for reflux reaction for 6 hours, giving a yield of 70%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 60min, giving a yield of 80%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-chlorobenzoate: the procedure was as in (4) in example 1, except that the reaction was terminated after 26min, and 4-chlorobenzoyl chloride was used as a starting material in a yield of 74%.
Example 22
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-bromobenzoate (compound No. B)4) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 89% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1.8 hours, and then heated to 78 ℃ for reflux reaction for 5 hours, giving a yield of 68%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 58min, giving a yield of 79%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-bromobenzoate: the procedure was as in (4) in example 1, except that the reaction was terminated after 28min, and 4-bromobenzoyl chloride was used as a starting material in a yield of 70%.
Example 23
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-methoxybenzoate (Compound No. B)5) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 90% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 2 hours, and then heated to 78 ℃ under reflux for 6 hours, giving a yield of 70%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the procedure was as in (3) in example 1, except that the reaction was stirred at room temperature for 60min, giving a yield of 73%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-methoxybenzoate: the procedure was as in (4) in example 1, except that the reaction was terminated after 30min, and 4-methoxybenzoyl chloride was used as a starting material in 79% yield.
Example 24
Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) dimethylcarbamate (Compound No. B)6) The method comprises the following steps:
(1) 2-hydroxy acethydrazide synthesis: the yield was 90% as in the step (1) in example 1.
(2) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiol: the procedure was as in step (2) of example 1, except that the mixture was first reacted at room temperature for 1.5 hours, and then heated to 78 ℃ for reflux reaction for 5.5 hours, giving a yield of 68%.
(3) Synthesis of 5-hydroxymethyl-1, 3, 4-oxadiazole-2-thiomethyl ether: the reaction was carried out in the same manner as in example 1, step (3), except that the reaction was stirred at room temperature for 50min, whereby the yield was 78%.
(4) Synthesis of methyl (5- (methylthio) -1,3, 4-oxadiazol-2-yl) 4-fluorobenzoate: the procedure was as in (4) in example 1, except that the reaction was terminated after 20min, and dimethylcarbamoyl chloride was used as a starting material in a yield of 81%.
The physicochemical properties and mass spectrum data of the synthesized 1,3, 4-oxadiazole thioether compounds containing sulfonic ester/carboxylic ester are shown in Table 1, and the nuclear magnetic resonance hydrogen spectrum (C: (M))1H NMR) and carbon Spectroscopy (13C NMR) data are shown in table 2.
TABLE 1 physicochemical Properties of the target Compounds and their Mass spectrometric data
TABLE 2 NMR and C spectra data for target compounds
Activity test example 1: the activity test of the target compounds for inhibiting rice bacterial blight and citrus canker pathogen indoors is shown in tables 3 and 4.
Taking target compounds as medicaments, respectively adding the synthesized A and B series target compounds and two commercial medicaments of bismerthiazol and thiediazole copper into NB liquid culture media to prepare NB liquid culture media with final concentrations of 100 mu g/mL, 50 mu g/mL and 0 mu g/mL of medicaments, respectively adding 40 mu L of rice bacterial blight (Xoo) into the three groups of NB liquid culture media, wherein one group of 0 mu g/mL is set as a control. Culturing the above bacterial solution in shaking table at 28 deg.C and 180rpm for 24-48h to logarithmic growth phase, and measuring OD (OD) value on enzyme labeling instrument595) And (4) determining the OD value of the culture medium without the three bacteria-added agents as the OD value of the bacteria liquid, and deducting the OD value as a background absorption value when calculating. The activity of the citrus canker pathogen was tested as above, but the final concentrations of the three groups were set at 200. mu.g/mL and 100. mu.g, respectivelyAnd 0. mu.g/mL, again with 0. mu.g/mL being a control. The inhibitory effects (inhibition rates) of the compounds on two kinds of bacterial blight of rice and bacterial canker of citrus were measured and calculated, and the results are shown in table 3.
The inhibition rate of the compound needs to be calculated by deducting and correcting the background OD value generated by the NB liquid culture medium, and the calculation formula for correcting the OD value and the inhibition rate is as follows:
the corrected OD value (OD value of bacteria-containing culture medium liquid OD value-OD value of non-bacteria-containing culture medium compound inhibition rate) (corrected OD value of control group bacterial liquid-corrected OD value of medicine-containing bacterial liquid)/corrected OD value of control group bacterial liquid
TABLE 3 Primary screening of bacteriostatic activity of target compounds A and B against bacterial blight of rice (Xoo) and bacterial canker of citrus (Xac)
As shown in Table 3, most of the compounds A had higher antibacterial activity against rice bacterial blight bacteria than the control drugs bismerthiazol and thiediazole copper. Wherein at the concentration of 100 mu g/mL, 12 compounds A1-A5、A11-A16And B2The inhibition rate of the bacterial blight of rice is higher than 90%. When the concentration of the drug is reduced to 50 mug/mL, 3 compounds A exist1、A2、A14The inhibition rate of the bacterial blight of rice is higher than 90 percent, which is far higher than 28.3 percent of the metconazole and 30.2 percent of the thiediazole copper. At a drug concentration of 200. mu.g/mL, there were 4 compounds A1、A2、A3And A8The inhibition rate of the citrus canker pathogenic bacteria reaches more than 90 percent. At a drug concentration of 100. mu.g/mL, there were 3 compounds A1、A2And A3The inhibition effect on the citrus canker pathogenic bacteria is between 69 and 82 percent and is superior to 58.2 percent of the control drug of bismerthiazol and 53.1 percent of thiediazole copper.
Setting 5 concentration gradients for part of target compounds with good inhibitory activity, and determining EC of the target compounds on rice bacterial blight (Xoo) and citrus canker pathogen (Xac)50The value is obtained. Determination of the actual target Compounds A and A according to the above-mentioned Experimental methodsAntibacterial activity and EC of B value50The values and results are shown in Table 4.
EC against bacterial blight of rice and canker citrus of part of the target Compounds in Table 450(μM)
As shown in Table 4, there were 10 of the compounds A1-A4And A11-A16Has good inhibition effect on rice bacterial blight and EC thereof50The values ranged from 50.1 to 112.5. mu.M, which is far superior to 253.5. mu.M for bismerthiazol and 467.4. mu.M for copper thielavide. At the same time, there are 4 compounds A1-A4The inhibition effect on citrus canker pathogenic bacteria is also good. Their EC50In the range of 95.8 to 155.2. mu.M, is superior to 274.3. mu.M for bismerthiazol and 406.3. mu.M for copper thielavides.
From tables 3 and 4, it can be seen that the 1,3, 4-oxadiazole thioether compounds have more significant antibacterial activity against rice bacterial blight disease, especially compound a1、A2And A3It will be subjected to in vivo potting experiments.
Activity test example 2: highly active Compound A1、A2And A3In vivo pot culture test on rice bacterial leaf blight.
(1) Protection effect of rice bacterial leaf blight living pot experiment
Compound A with better activity to pathogenic bacteria of bacterial leaf blight of rice1、A2And A3And contrast agents of bismerthiazol and thiediazole copper are respectively prepared into medicine-containing solutions with the concentration of 200 mu g/mL by using 0.1% Tween solutions, and the medicine-containing solutions are sprayed on the surfaces of leaves of rice until liquid drops are dripped. After one day, the leaf tips were cut off with scissors with bacterial liquid of bacterial blight of rice at a distance of 1-2cm from the leaf tips, and the wounds were soaked in the bacterial liquid for about 30s, while a control group of 0.1% Tween solution without drug was provided. Each 30 rice seedlings are treated, the disease condition is checked 14 days after the application of the pesticide, the length of disease spots of rice leaves is recorded, the disease index and the prevention effect are calculated, and the result is obtainedSee table 5.
(2) Treatment effect of rice bacterial leaf blight living pot experiment
Cutting off the leaf apex at a position 1-2cm away from the leaf apex of the rice leaf by using scissors stained with pathogenic bacteria of bacterial leaf blight of rice, and soaking the wound in the bacterial liquid for about 30 s. One day later, the compound A with better activity to pathogenic bacteria of bacterial leaf blight of rice1、A2And A3And contrast agents of bismerthiazol and thiediazole copper are respectively prepared into medicine-containing solutions with the concentration of 200 mu g/mL by using 0.1% Tween solutions, and the medicine-containing solutions are sprayed on the surfaces of leaves of rice until liquid drops are dripped. Meanwhile, a 0.1% Tween solution control group without adding medicament is arranged. Each 30 rice seedlings are treated, the disease incidence condition is checked after the application of the pesticide for 14 days, the length of disease spots of the rice leaves is recorded, the disease index and the prevention effect are calculated, and the results are shown in table 6.
Control effect (%) - (control group lesion length-treatment group lesion length)/control group lesion length x 100
TABLE 5 target Compound A1、A2And A3Activity experiment result for protecting living potted plant of rice bacterial leaf blight (Xoo)
TABLE 6 target Compound A1、A2And A3Experimental result of activity of living pot culture of rice bacterial blight (Xoo)
As shown in tables 5 and 6 above, the target Compound A was tested at a drug concentration of 200. mu.g/mL2And A3The protection, prevention and control effects on the rice pot culture are respectively 68.6 percent and 62.3 percent, which are superior to 49.6 percent of the control drug bismerthiazol and 42.2 percent of the thiediazole copper. Target Compound A tested as shown in Table 61、A2And A3The treatment, prevention and control effects on the rice potted plant are respectively 44.6 percent, 62.3 percent and 56.0 percent, which are superior to the effects on leaves42.9% of cumidine and 36.1% of thiabendazole.
In conclusion, the series of 1,3, 4-oxadiazole compounds containing sulfonate/carboxylate structures have excellent antibacterial activity, and particularly the compound A1、A2、A3And A4Has the most excellent bacteriostatic activity on rice bacterial blight and citrus canker pathogen, and is superior to the bacteriostatic activity of control drugs of bismerthiazol and thiediazole copper.
The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.