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Synthetic method for 2-benzyl cyclopentanone

A technology of benzylcyclopentanone and a synthesis method is applied in the field of preparation of organic pharmaceutical intermediates, and can solve the problems of sodium amide easily causing fire, low total product yield, useless by-products, etc. cost, waste reduction effect

Active Publication Date: 2014-01-15
KUNSHAN RIKITA PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0014] Method 3) The total yield of the product is low, sodium amide is easy to cause fire, and the by-products are useless

Method used

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  • Synthetic method for 2-benzyl cyclopentanone
  • Synthetic method for 2-benzyl cyclopentanone
  • Synthetic method for 2-benzyl cyclopentanone

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] 1) Friedel-Crafts acylation and esterification (synthesis of methyl 5-benzoylvalerate, ROH=CH30H):

[0046] Add 80ml of benzene and 0.22mol of aluminum trichloride into the reaction flask, add dropwise 0.1mol of adipic anhydride (dissolved in 20ml of benzene) at 31-55°C, then react at 40-55°C for 2 hours, add dropwise 0.5mol of methanol, Continue to react at 40-55°C for 2 hours, add the reaction mixture to 200ml of water for hydrolysis, statically separate layers, wash the benzene layer with aqueous sodium carbonate solution, distill benzene at 100°C, and the residue is 5-benzoylvaleric acid methyl Ester, the product is light yellow, the freezing point is 35-36.5°C, the content is over 98%, and the yield is 90-92%.

[0047] 2) Condensation and cyclization reaction (synthesis of 2-benzoylcyclopentanone, tripotassium phosphate method) 0.1mol methyl 5-benzoylvalerate, 0.1mol tripotassium phosphate and 50ml DMF were refluxed for 12 hours, Cool down to about 30°C, remove...

Embodiment 2

[0051] 1) Friedel-Crafts acylation and esterification (synthesis of methyl 5-benzoylvalerate, ROH=CH3OH):

[0052] Add 80ml of benzene and 0.22mol of aluminum trichloride into the reaction flask, add dropwise 0.1mol of adipic anhydride (dissolved in 20ml of benzene) at 31-55°C, then react at 50-70°C for 2 hours, add dropwise of 0.5mol of methanol, Continue to react at 50-70°C for 2 hours, add the reaction mixture to 200ml of water for hydrolysis, statically separate layers, wash the benzene layer with aqueous sodium carbonate solution, distill benzene at 100°C, and the residue is 5-benzoylvaleric acid methyl Ester, the product is light yellow, the freezing point is 35-36.5°C, the content is over 98%, and the yield is 90-92%.

[0053] 2) Condensation cyclization reaction (synthesis of 2-benzoylcyclopentanone, triethylamine method)

[0054]0.1mol of methyl 5-benzoylvalerate, 0.1mol of triethylamine and 50ml of DMF were put into the autoclave,

[0055] React at 150-155°C for ...

Embodiment 3

[0059] 1) Friedel-Crafts acylation and esterification (synthesis of methyl 5-benzoylvalerate):

[0060] Add 80ml of benzene and 0.3mol of aluminum trichloride into the reaction flask, add dropwise 0.1mol of adipic anhydride (dissolved in 20ml of benzene) at 31-55°C, then react at 60-75°C for 2 hours, add dropwise of 0.4mol of ethanol, Continue to react at 60-75°C for 2 hours, add the reaction mixture to 200ml of water for hydrolysis, statically separate layers, wash the benzene layer with aqueous sodium carbonate solution, distill benzene at 100°C, and the residue is 5-benzoylvaleric acid methyl Ester, the product is light yellow, the freezing point is 35-36.5°C, the content is over 98%, and the yield is 90-92%.

[0061] 2) Condensation and cyclization reaction (synthesis of 2-benzoylcyclopentanone, tripotassium phosphate method) 0.2mol of methyl 5-benzoylvalerate, 0.2mol of tripotassium phosphate and 1000ml of DMF were refluxed for 12 hours, Cool down to about 30°C, remov...

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Abstract

The invention discloses a synthetic method for 2-benzyl cyclopentanone. Benzene and adipic anhydride are subjected to Friedel-Crafts and esterification one-pot reaction to synthesize 5-benzoylpentanoic acid ester, 5-benzoylpentanoic acid ester is subjected to acyloin ester condensation and cyclization reactions to produce 2-benzoyl cyclopentanone, and 2-benzoyl cyclopentanone is subjected to selective hydrogenation reduction reaction to obtain the 2-benzyl cyclopentanone product. According to the invention, 2-benzyl cyclopentanone can be synthesized at a low cost, waste emission is reduced and the yield of 2-benzyl cyclopentanone is improved.

Description

[0001] technical field [0002] The invention relates to a method for preparing an organic drug intermediate, in particular to a method for synthesizing 2-benzylcyclopentanone. Background technique [0003] 2-benzylcyclopentanone is an organic pharmaceutical intermediate, which can be used for the synthesis of loxoprofen, a non-steroidal anti-inflammatory analgesic. The methods are: [0004] 1) Alkylation and decarboxylation of benzyl chloride and 2-methoxycarbonyl cyclopentanone, the total yield is about 60%, (see literature Organic Syntheses, Coll. Vol. 5, p.76 (1973); Vol. 45, p.7 (1965).) [0005] Its chemical reaction formula is as follows: [0006] [0007] 2) Cyclopentanone is produced by alkylation (benzylation) of enamine, and the total yield is less than 30%. The reaction formula is as follows: [0008] [0009] 3) Cyclopentanone is directly benzylated under the catalysis of sodium amide to obtain the product, with a total yield of less than 30%, (see lit...

Claims

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Application Information

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IPC IPC(8): C07C49/657C07C45/65
CPCC07C45/455C07C45/65C07C51/083C07C67/08C07C2601/08C07C49/657C07C49/792C07C69/738C07C59/84
Inventor 李德宝习文兵廖育能吴俊飞
Owner KUNSHAN RIKITA PHARMA
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