CN103288777A - Synthesis method of key intermediate of tebuthiuron, namely 2-methylamino-5-tert-butyl-1, 3, 4-thiadiazole - Google Patents
Synthesis method of key intermediate of tebuthiuron, namely 2-methylamino-5-tert-butyl-1, 3, 4-thiadiazole Download PDFInfo
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Abstract
The invention discloses a synthesis method of a key intermediate of tebuthiuron, namely 2-methylamino-5-tert-butyl-1, 3, 4-thiadiazole. Derivatives of 4-methyl-3-thiosemicarbazide and trimethylacetic acid are taken as raw materials, and condensation and dehydration cyclization reactions are performed under acid conditions in the presence of an organic solvent medium and a hydration agent to obtain the 2-methylamino-5-tert-butyl-1, 3, 4-thiadiazole. According to the synthesis method disclosed by the invention, environmental pollution caused by a large amount of wastewater containing phosphorus, which is produced by taking phosphoric acid, polyphosphoric acid and the like as dehydration reagents, can be effectively avoided; simultaneously, the reaction yield is high, byproducts are few, and the solvent can be recovered and applied mechanically; and the synthesis method further has the advantage of very high atom economy and is in line with the direction of green chemical development.
Description
Technical field
The invention belongs to the compound field, relate in particular to a kind of terbufos benzthiazuron key intermediate 2-methylamino-5-tertiary butyl-1,3 of green non-pollution, the synthetic method of 4-thiadiazoles.
Background technology
Terbufos benzthiazuron (tebuthiuron), it is a kind of carbamide herbicides of the natural disposition of going out, annual and perennial Gramineae and broadleaf weeds all there are good preventive effect, can be used for preventing and treating shrub, the Gramineae in the sugarcane field and broadleaf weeds in bare place weeds, the pasture.
The structural formula of terbufos benzthiazuron is shown in V, and at DE3113328A1, documents such as DE3314190 and GB1195672 all adopt methyl isocyanate and 2-methylamino-5-tertiary butyl-1,3, the synthetic terbufos benzthiazuron of the mode of 4-thiadiazoles reaction; At US3803164A, US3887572A, all reported key intermediate 2-methylamino-5-tertiary butyl-1 in the documents such as US4283543A, 3,4-thiadiazoles synthetic method has all adopted under the phosphorous dehydrated reagent effect such as polyphosphoric acid, phosphorus trichloride, phosphorus pentachloride, phosphorus oxychloride, prepares 2-methylamino-5-tertiary butyl-1 by the method for 4-methyl-3-thiosemicarbazide and trimethylacetic acid or trimethyl-acetyl chloride cyclodehydration, 3,4-thiadiazoles.Because all having adopted phosphorous dehydrated reagent and consumption in these bibliographical informations all is the several times of reaction substrate, this class technology can produce a large amount of phosphorus-containing wastewaters, and the wastewater treatment difficulty is big, and environmental pollution is serious, does not meet the direction of Green Chemistry development.
Summary of the invention
The objective of the invention is to overcome the defective that exists in the prior art, a kind of terbufos benzthiazuron key intermediate 2-methylamino-5-tertiary butyl-1,3 is provided, the preparation method of 4-thiadiazoles, can solve the defective that traditional processing technology exists, environmental protection, pollution-free.
The terbufos benzthiazuron key intermediate 2-methylamino-5-tertiary butyl-1,3, the synthetic method of 4-thiadiazoles, be raw material with trimethylacetic acid derivative shown in 4-methyl-3-thiosemicarbazide shown in the general formula (I) and the logical formula II, under acidic conditions, and obtain 2-methylamino-5-tertiary butyl-1,3 through condensation, dehydration condensation reaction under organic solvent medium and the dewatering agent existence, the 4-thiadiazoles, reaction formula is as follows:
Wherein, R is hydroxyl, chlorine, oxyethyl group, alkoxyl group or chloro phenoxy group;
It is characterized in that described dewatering agent is selected from chlorsulfonic acid, sulfur oxychloride, SULPHURYL CHLORIDE, oleum, diacetyl oxide, dicyclohexylcarbodiimide or C
2-10The acyl chlorides of lipid acid in one or more; Described organic solvent medium is for to be the organic solvent inert medium to the trimethylacetic acid derivative; The mol ratio of 4-methyl-3-thiosemicarbazide and trimethylacetic acid derivative and dewatering agent is 1:1～4:2～5; Temperature of reaction is-10 ℃～160 ℃; Reaction adds water after finishing, and regulating material pH value with alkali is 6～10, separates obtaining organic layer, and underpressure distillation goes out organic solvent, namely obtains 2-methylamino-5-tertiary butyl-1,3, the 4-thiadiazoles.
Said raw material 4-methyl-3-thiosemicarbazide (I) derives from method currently reported and/or that use in above-mentioned preparation method, for example can be by EP0339964A2, and US4132736, the method for bibliographical informations such as WO02081438A2 prepares.
The trimethylacetic acid derivative can be trimethylacetic acid, trimethyl-acetyl chloride, trimethyl acetic anhydride or trimethylacetic acid ester.The trimethylacetic acid ester is selected from methyl trimethylacetate, tri-methyl ethyl acetate, trimethylacetic acid butyl ester, trimethylacetic acid phenyl ester, trimethylacetic acid trichlorine phenyl ester or trimethylacetic acid pentachlorophenyl ester.Wherein the reactive behavior with the trimethylammonium acyl chlorides is the strongest, secondly is the active ester of trimethylacetic acid, and reactive behavior is stronger trimethylacetic acid trichlorine phenyl ester, trimethylacetic acid pentachlorophenyl ester etc.
Acidic conditions in the reaction process refers to the pH value less than 2 condition, can be by adding mineral acids such as hydrochloric acid, sulfuric acid, or organic acids such as acetic acid, trimethylacetic acid are regulated.
Because the trimethylacetic acid derivative has stronger reactive behavior, produce side reaction for avoiding itself and solvent as reaction medium, should select it is organic solvent inert.Described organic solvent medium can be selected from one or more in benzene and derivative thereof, acetonitrile, sherwood oil, hexanaphthene, tetrahydrofuran (THF), dioxan, dimethyl formamide, chloroparaffin, the ether organic solvent.Work as chlorsulfonic acid, oleum etc. are during as dewatering agent, because chlorsulfonic acid, oleum etc. have stronger sulfurization, and solvent should select chloroparaffins such as methylene dichloride, chloroform, ethylene dichloride to be advisable.
Experimental result shows, in obtaining the process of intermediate compound (III), 4-methyl-3-thiosemicarbazide (I) and trimethylacetic acid derivative (II) condensation need higher temperature of reaction for making to react completely, significant reaction was accelerated when active strong trimethyl-acetyl chloride was wanted more than 50 ℃, active more weak trimethylacetic acid active ester, trimethyl acetic anhydride, trimethylacetic acid then needs higher temperature of reaction, and refluxing down when making solvent with dimethyl formamide, temperature of reaction reaches 152 ℃.
Experimental result shows, with chlorsulfonic acid, sulfur oxychloride, SULPHURYL CHLORIDE, oleum during as dewatering agent, it is unsuitable too high to add fashionable temperature of reaction, temperature of reaction is preferably-10 ℃-～20 ℃, otherwise unreacted 4-methyl-3-thiosemicarbazide (I) and trimethylacetic acid derivative (II) all can with dewatering agent generation side reaction, be unfavorable for the purification of transformation efficiency and product, the temperature that adds dewatering agent is advisable to be lower than 20 ℃.With diacetyl oxide, dicyclohexylcarbodiimide or C
2-10The acyl chlorides of lipid acid during as dewatering agent, because this type of dewatering agent does not have strong oxidizing property, can be under the required temperature of synthetic mesophase compound (III) directly add, can add down for 83 ℃ at reflux temperature when making solvent with ethylene dichloride, temperature of reaction can be 20 ℃～160 ℃.。
The mol ratio of 4-methyl-3-thiosemicarbazide and trimethylacetic acid derivative is preferably 1:1～2.
Reaction finishes to regulate material pH value with alkali and is preferably 7～9.
Described alkali is can be alkali-metal mineral alkali, as sodium hydroxide, potassium hydroxide etc.; Alkali-metal carbonate, supercarbonate are as yellow soda ash, salt of wormwood, sodium bicarbonate etc.; Or nitrogenous base, as ammoniacal liquor, triethylamine, pyridine etc.
During as dewatering agent, the by-product of reaction is sulfuric acid and hydrochloric acid with chlorsulfonic acid, sulfur oxychloride, SULPHURYL CHLORIDE, oleum, and available alkali lye is neutralized into sodium-chlor and sodium sulfate, with diacetyl oxide, C
2-10The by-product of the acyl chlorides of lipid acid recyclable dewatering agent and water reaction during as dewatering agent, realize zero release of pollutant.
The weedicide terbufos benzthiazuron key intermediate 2-methylamino of the present invention-5-tertiary butyl-1,3, the preparation method of 4-thiadiazoles can effectively solve the environmental pollution that a large amount of phosphorus-containing wastewaters of producing as dehydrated reagent with phosphoric acid, polyphosphoric acid etc. cause, few, the solvent recuperation of Fan Ying productive rate height, by-product is applied mechanically simultaneously, have very high Atom economy, meet the direction of Green Chemistry development.
The present invention is described in further detail for embodiment by the following examples.But this should be interpreted as that the scope of the above-mentioned theme of the present invention only limits to following example.Do not breaking away under the above-mentioned technological thought situation of the present invention, various replacements or change according to ordinary skill knowledge and customary means are made include within the scope of the invention.
Embodiment
Embodiment 1
4-methyl-3-thiosemicarbazide (I) 10.5g(0.1mol that adds 99% content in the reaction flask of 100mL) and 30mL 1, the 2-ethylene dichloride, be warming up to 80 ℃, close heating system, in system, be added dropwise to trimethyl-acetyl chloride 18.3g(0.15mol), splash into the afterreaction heat release, interior temperature can rise to 83 ℃, ethylene dichloride is refluxed, open heating system after dropwising and continue the insulation backflow, cooling when hydrogen chloride gas not had is emitted, when interior temperature drop is low to moderate 15-20 ℃, be added dropwise to chlorsulfonic acid 13.3g(0.1), be no more than 25 ℃ with temperature in the frozen water control in the dropping process, be added dropwise to complete the 15-20 ℃ of insulation reaction in back 1 hour.The aqueous sodium hydroxide solution of adding 20% is regulated about PH to 8, and this moment, the heat release of Nei Wenyin acid-base neutralisation can reach 50-60 ℃, told organic layer, reclaim ethylene dichloride, obtain 2-methylamino-5-tertiary butyl-1,3,4-thiadiazoles product 17.3g, relative content 93%, yield 94.1%.
Embodiment 2
4-methyl-3-thiosemicarbazide (I) 10.5g(0.1mol that adds 99% content in the reaction flask of 100mL) and 30mL 1, the 2-ethylene dichloride, be warming up to 80 ℃, close heating system, in system, be added dropwise to trimethyl-acetyl chloride 18.3g(0.15mol), splash into the afterreaction heat release, interior temperature can rise to 83 ℃, and ethylene dichloride is refluxed, and opens heating system after dropwising and continues the insulation backflow, be added dropwise to acetic anhydride 10.2g(0.1 under refluxing when hydrogen chloride gas not had is emitted), be added dropwise to complete back backflow insulation reaction after 1 hour, reclaim under reduced pressure ethylene dichloride and by-product acetic acid add the ethylene dichloride of 20mL again, aqueous sodium hydroxide solution with 20%, regulate about PH to 8, interior temperature remains on 50-60 ℃, tells organic layer, reclaim ethylene dichloride again, obtain 2-methylamino-5-tertiary butyl-1,3,4-thiadiazoles product 17.2g, relative content 95%, yield 95.6%.
Embodiment 3
4-methyl-3-thiosemicarbazide (I) 10.5g(0.1mol that adds 99% content in the reaction flask of 100mL) and 30mL 1, the 2-ethylene dichloride, be warming up to 80 ℃, close heating system, in system, be added dropwise to trimethyl-acetyl chloride 18.3g(0.15mol), splash into the afterreaction heat release, interior temperature can rise to 83 ℃, and ethylene dichloride is refluxed, and opens heating system after dropwising and continues the insulation backflow, be added dropwise to Acetyl Chloride 98Min. 7.9g(0.1 under refluxing when hydrogen chloride gas not had is emitted), be added dropwise to complete back backflow insulation reaction after 1 hour, reclaim under reduced pressure ethylene dichloride and by-product acetic acid add the ethylene dichloride of 20mL again, aqueous sodium hydroxide solution with 20%, regulate about PH to 18, interior temperature remains on 50-60 ℃, tells organic layer, reclaim ethylene dichloride again, obtain 2-methylamino-5-tertiary butyl-1,3,4-thiadiazoles product 19.8g, relative content 82%, yield 94.9%.
Claims (8)
1. terbufos benzthiazuron key intermediate 2-methylamino-5-tertiary butyl-1,3, the synthetic method of 4-thiadiazoles, be raw material with trimethylacetic acid derivative shown in 4-methyl-3-thiosemicarbazide shown in the general formula (I) and the logical formula II, under acidic conditions, and obtain 2-methylamino-5-tertiary butyl-1,3 through condensation, dehydration condensation reaction under organic solvent medium and the dewatering agent existence, the 4-thiadiazoles, reaction formula is as follows:
Wherein, R is hydroxyl, chlorine, oxyethyl group, alkoxyl group or chloro phenoxy group;
It is characterized in that described dewatering agent is selected from chlorsulfonic acid, sulfur oxychloride, SULPHURYL CHLORIDE, oleum, diacetyl oxide, dicyclohexylcarbodiimide or C
2-10The acyl chlorides of lipid acid in one or more; Described organic solvent medium is for to be the organic solvent inert medium to the trimethylacetic acid derivative; The mol ratio of 4-methyl-3-thiosemicarbazide and trimethylacetic acid derivative and dewatering agent is 1:1～4:2～5; Temperature of reaction is-10 ℃～160 ℃; Reaction adds water after finishing, and regulating material pH value with alkali is 6～10, separates obtaining organic layer, and underpressure distillation goes out organic solvent, namely obtains 2-methylamino-5-tertiary butyl-1,3, the 4-thiadiazoles.
2. synthetic method as claimed in claim 1 is characterized in that, described acidic conditions is that the pH value is less than 2.
3. synthetic method as claimed in claim 1, it is characterized in that described organic solvent medium is selected from one or more in benzene and derivative thereof, acetonitrile, sherwood oil, hexanaphthene, tetrahydrofuran (THF), dioxan, dimethyl formamide, chloroparaffin, the ether organic solvent.
4. synthetic method as claimed in claim 3 is characterized in that, when dewatering agent was chlorsulfonic acid, sulfur oxychloride, SULPHURYL CHLORIDE or oleum, temperature of reaction was-10 ℃～20 ℃.
5. synthetic method as claimed in claim 3 is characterized in that, when dewatering agent is diacetyl oxide, dicyclohexylcarbodiimide or C
2-10The acyl chlorides of lipid acid the time, temperature of reaction is 20 ℃～160 ℃.
6. synthetic method as claimed in claim 1 is characterized in that, the mol ratio of 4-methyl-3-thiosemicarbazide and trimethylacetic acid derivative is 1:1～2.
7. synthetic method as claimed in claim 1 is characterized in that, it is 7～9 that reaction finishes to regulate material pH value with alkali.
8. synthetic method as claimed in claim 7 is characterized in that, described alkali is sodium hydroxide, potassium hydroxide yellow soda ash, salt of wormwood, sodium bicarbonate, ammoniacal liquor, triethylamine or pyridine etc.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105524017A (en) * | 2015-12-24 | 2016-04-27 | 江苏瀚联生物科技有限公司 | Preparation method of 2-methylamino-5-t-butyl-1,3,4-thiadiazole |
| CN105669592A (en) * | 2016-03-21 | 2016-06-15 | 盐城南方化工有限公司 | Tebuthiuron synthesis method |
| CN108794427A (en) * | 2018-07-13 | 2018-11-13 | 江苏快达农化股份有限公司 | A kind of synthetic method of 1,3,4- thiadiazoles derivatives |
| CN109251188A (en) * | 2018-09-26 | 2019-01-22 | 河北工业大学 | A kind of preparation method of 2- methylamino -5- tert-butyl -1,3,4- thiadiazoles |
| CN110372634A (en) * | 2019-07-29 | 2019-10-25 | 宁夏晟丰元化工有限公司 | A method of synthesis 2- methylamino -5- tert-butyl -1,3,4- thiadiazoles |
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| CN102603672A (en) * | 2012-02-15 | 2012-07-25 | 江苏快达农化股份有限公司 | Method for synthesizing tebuthiuron technical material |
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| US3803164A (en) * | 1972-05-22 | 1974-04-09 | Lilly Co Eli | Simplified one vessel preparation of 1-(5-alkyl-1,3,4-thiadiazol-2-yl)-1,3-dialkyl-ureas with azeotropic drying |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105524017A (en) * | 2015-12-24 | 2016-04-27 | 江苏瀚联生物科技有限公司 | Preparation method of 2-methylamino-5-t-butyl-1,3,4-thiadiazole |
| CN105524017B (en) * | 2015-12-24 | 2017-06-30 | 江苏瀚联生物科技有限公司 | The preparation method of the thiadiazoles of 2 methylamino, 5 tert-butyl group 1,3,4 |
| CN105669592A (en) * | 2016-03-21 | 2016-06-15 | 盐城南方化工有限公司 | Tebuthiuron synthesis method |
| CN105669592B (en) * | 2016-03-21 | 2019-04-12 | 盐城南方化工有限公司 | A kind of synthetic method of terbufos benzthiazuron |
| CN108794427A (en) * | 2018-07-13 | 2018-11-13 | 江苏快达农化股份有限公司 | A kind of synthetic method of 1,3,4- thiadiazoles derivatives |
| CN108794427B (en) * | 2018-07-13 | 2022-07-29 | 江苏快达农化股份有限公司 | Synthetic method of 1,3, 4-thiadiazole derivative |
| CN109251188A (en) * | 2018-09-26 | 2019-01-22 | 河北工业大学 | A kind of preparation method of 2- methylamino -5- tert-butyl -1,3,4- thiadiazoles |
| CN110372634A (en) * | 2019-07-29 | 2019-10-25 | 宁夏晟丰元化工有限公司 | A method of synthesis 2- methylamino -5- tert-butyl -1,3,4- thiadiazoles |
| CN110372634B (en) * | 2019-07-29 | 2021-03-19 | 宁夏常晟药业有限公司 | Method for synthesizing 2-methylamino-5-tert-butyl-1, 3, 4-thiadiazole |
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Application publication date: 20130911 |