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Synthetic method of 3,4,5-tri-substituted oxazole-2-one

A synthetic method and tri-substitution technology, applied in 3 fields, can solve the problems of poor substrate compatibility, harsh reaction conditions, low yield, etc., and achieve the effects of short steps, simple operation and good functional group compatibility

Inactive Publication Date: 2014-11-05
ZHEJIANG NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0017] In summary, although some synthetic methods of multi-substituted oxazol-2-ones have been reported, there are some disadvantages such as harsh reaction conditions, use of highly toxic or expensive chemical reagents, low yield, poor substrate compatibility, etc. shortcoming
So far, there are very few methods for the simple, efficient and economical synthesis of 3,4,5-trisubstituted oxazol-2-ones

Method used

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  • Synthetic method of 3,4,5-tri-substituted oxazole-2-one

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Experimental program
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Effect test

preparation example 1

[0049] Raw Material Preparation Example 1 Synthesis of Raw Material Compound II

[0050] The compound shown in structural formula II is synthesized according to the method of literature (Istrate F.M.et.al, Org.Lett.2008, 10, 925). Taking compound 1a as an example, the reaction equation and operation steps are as follows:

[0051]

[0052] Add phenylacetylene bromide (90mg, 0.5mmol), tert-butyl N-benzylcarbamate (124mg, 0.6mmol), potassium phosphate (212mg, 1.0mmol), copper sulfate pentahydrate (25mg, 0.1mmol) and 1,10-phenanthroline (36mg, 0.2mmol), were dissolved in 2mL of toluene to obtain a reaction system. The reaction system was reacted at 80° C. for 8 hours, then quenched by adding 10 mL of water, and extracted three times with ethyl acetate (10 mL). After the organic phases were combined, they were washed with aqueous sodium bicarbonate solution and saturated brine, and the obtained organic layer was dried over anhydrous sodium sulfate, and then the solvent was remo...

Embodiment 1

[0056] Add palladium acetate (2.8mg, 0.0125mmol), tri-tert-butylphosphine (5.0mg, 0.025mmol) and potassium carbonate (41mg, 0.30mmol) into 1mL N, N-dimethylformamide (DMF) to dissolve, place in In a 10 mL round bottom flask, tert-butyl N-benzyl-N-phenylethynylcarbamate 1a (77 mg, 0.25 mmol) was added, followed by iodobenzene 2a (56 mg, 0.28 mmol) to obtain a reaction system. The reaction system was reacted at 50° C. for 8 hours, then quenched by adding 10 mL of water, and extracted three times with ethyl acetate (10 mL). After the combined organic phases were washed with aqueous sodium bicarbonate and saturated brine, the organic layer obtained was dried over anhydrous sodium sulfate, and then the solvent was removed by rotary evaporation, and then separated by silica gel (300-400 mesh) column chromatography (eluent: Petroleum ether / ethyl acetate=11 / 1, volume ratio) gave 75 mg (yield: 92%) of 3,4,5-trisubstituted oxazol-2-ones as a yellow solid.

[0057] yellow solid 1 H-NMR...

Embodiment 2

[0060] Except that o-methyl iodobenzene 2b was used instead of iodobenzene 2a in Example 1, the remaining operation steps were the same as in Example 1, and the yield was 82%. The product: yellow liquid.

[0061] yellow liquid 1 H-NMR (CDCl 3 , 400MHz): δ1.84(s, 3H), 4.52(d, J=15.2Hz, 1H), 4.65(d, J=15.2Hz, 1H), 6.87-6.98(m, 2H), 7.10-7.25( m, 9H), 7.27-7.39 (m, 2H), 7.41-7.50 (m, 1H); 13 C-NMR (CDCl 3 , 100MHz): δ19.0, 45.7, 122.0, 123.5, 126.4, 126.6, 127.4, 127.8, 127.9, 128.0, 128.4, 128.5, 130.4, 130.7, 131.1, 134.3, 135.9, 139.1, 154.9 / m z): 341 (M + , 8), 327(1), 250(15), 222(25), 179(21); HRMS(EI) calcd for C 23 h 19 NO 2 (M + ), 341.1416, Found 341.1411. It shows that the yellow liquid is 3-benzyl-4-o-methylphenyl-5-phenyl-oxazol-2-one shown in structural formula 4b.

[0062]

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Abstract

The invention discloses a synthetic method of 3,4,5-tri-substituted oxazole-2-tone. The synthetic method comprises the steps of: dissolving a palladium catalyst, tri-tert-butylphosphine and alkali in an organic solvent, adding N-acetenyl carbamic acid tert-butyl ester and halohydrocarbon to form a reaction system, and completely reacting at the temperature of 25 DEG C-70 DEG C to prepare the 3,4,5-tri-substituted oxazole-2-one. The synthetic method is short in step, only needs one step, is simple in operation, high in reaction efficiency, wide in substrate applicability and capable of smoothly introducing various substituent groups at a third position, a fourth position and a fifth position, is a low-temperature reaction, is soft in condition and strong in practical applicability and has a bigger implementation value and socioeconomic performance.

Description

technical field [0001] The invention relates to the field of chemical synthesis, in particular to a method for synthesizing 3,4,5-trisubstituted oxazol-2-ones. Background technique [0002] Oxazol-2-one is an unsaturated five-membered heterocyclic compound containing nitrogen and oxygen heteroatoms. It is an important class of organic synthesis intermediates and can be used in the synthesis of amino acids, amino alcohols, dipeptides and other compounds. Oxazol-2-one also has wide application potential and development value in the fields of material science, pesticide and medicine. The structural formula of oxazol-2-one is as follows: [0003] [0004] Oxazol-2-one antibacterial drugs are a new class of chemically synthesized antibacterial drugs after sulfonamides and fluoroquinolones, which can inhibit multi-drug resistant Gram-positive bacteria. With the continuous increase of clinical drug-resistant strains, oxazol-2-ones are becoming a new class of promising new synt...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D263/38C07D413/04C07D409/04B01J31/28
Inventor 朱钢国卢增辉刘鸽罗芳夏思苑
Owner ZHEJIANG NORMAL UNIVERSITY