Sciencemadness Discussion Board

synthesis of O-Chlorophenyl cyclopentyl Ketone

cucei - 28-10-2012 at 22:09

I was searching for a synthesis of O-Chlorophenyl cyclopentyl Ketone (besides the classical synthesis with cyclopentyl magnesium bromide and o-chlorobenzonitrile) and found two interesting synthesis in the same publication . . . .
Zhang, Pang and Li, Lian-Chu(1986) 'Synthesis of α,β-Unsaturated Ketones via Enamines', Synthetic
Communications, 16: 8, 957 — 965
O-Chlorobenzoylcyclopentene (3C).

To 1-morpholinocyclopentene (46 g, 0.30 mol) in chloroform (450 ml) was added triethylamine
(31.3 g, 0.31 mol) first and then a solution of o-chlorobenzoyl chloride (54.3 g, 0.31 rnol) in chloroform (150 ml) with stirring at 38-42 degrees in about 1 hour. Stirring was continued for another hour and the reaction mixture was stood overnight. It was washed twice with sodium carbonate solution and twice with water and after dried (MgSO4 ), chloroform was removed successively by evaporation and then thrice with anhydrous methanol to give 1C as a dark red, viscous oil . The crude (1C) was dissolved in anhydrous ethanol (150 ml) and decolorized by boiling with active charcoal (10 g) and filtered. The filtrate was hydrogenated with Adams' Pt02
(1.0 g) at ambient pressure and temperature; hydrogen (0.3 mol) was absorbed in about 2 hour. The resulting oil obtained after removal of catalysis and evaporation was dissolved in cold 6N HCl acid (50 ml) and extracted twice with toluene. The combined toluene extract was washed twice with a small amount of 6N HCl acid, twice with water and dried (MgSO4) . The toluene extract was fractionated to give a mixture of (3C) and (4C), b.p. 114-132/3 mm, 17.8 g.

Some toluene (50 ml was mixed with the combined HCl acid extract and the mixture was refluxed for 2 hours. The toluene layer was separated and the acid layer was extracted once with
toluene. The combined toluene layer and extract was washed twice with water and dried (MgSO4 ). Removal of toluene and distillation gave 3C b.p. 112-116°/0.l mm, 28.9 g, 46.7% yield

O-Chlorophenyl cyclopentyl Ketone (4C).

Pure and impure 3C were combined and hydrogenated to give (4C), b.p. 94-96O/0.05 mm , 37.5 g, 60% yield
.
And in the same publication comes a reference to another synthesis of the same Ketone of interest.

4C had been synthesized previously by addition of cyclopentyl magnesium bromide to o-chlorobenzonitrile and by Nenitzescu reaction of o-chlorobenzoyl chloride and
cyclopentene with aluminium chloride as catalyst in cyclohexane( reference 1).. The yields obtained in both cases were less than 30% .

1.-S. L. Yeh, Org. Chem. and Biochem. (Peking University), 2, 14 ( 1973),

If anyone has another synthesis of the same ketone i would appreciate the information.

solo - 29-10-2012 at 07:22

....there is a five step review on this site.....solo


http://www.ch.ic.ac.uk/local/projects/badin/index.html

solo - 1-11-2012 at 07:14



The Improvement of the Synthetic Method of o-Chlorophenyl Cyclopentyl Ketone
Zhang Lijuan; Li Baozhang(Liaoning
CHINESE JOURNAL OF MEDICINEL CHEMISTRY
1995年01期
http://www.cnki.net/kcms/detail/detail.aspx?filename=ZGYH501...


Abstract
o-chlorophenyl cyclopentl ketones were prepared with cyclopentene and o-chloro-benzoyl chloride.This synthesis made improvement on the synthetic method of a patent report.It raised the yield from 50%～60% to 81.62%, and the yield and quality were quite stable so that the industrialization of production could be achived.

http://www.4shared.com/office/GGaHEfAV/an_improved_method_of...

[Edited on 1-11-2012 by solo]

solo - 3-11-2012 at 01:30

Quote: Originally posted by solo  


The Improvement of the Synthetic Method of o-Chlorophenyl Cyclopentyl Ketone
Zhang Lijuan; Li Baozhang(Liaoning
CHINESE JOURNAL OF MEDICINEL CHEMISTRY
1995年01期
http://www.cnki.net/kcms/detail/detail.aspx?filename=ZGYH501...


Abstract
o-chlorophenyl cyclopentl ketones were prepared with cyclopentene and o-chloro-benzoyl chloride.This synthesis made improvement on the synthetic method of a patent report.It raised the yield from 50%～60% to 81.62%, and the yield and quality were quite stable so that the industrialization of production could be achived.

http://www.4shared.com/office/GGaHEfAV/an_improved_method_of...

[Edited on 1-11-2012 by solo]


Here is the english translation of the article....solo

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