Cyclopentyl bromide

The reaction of cyclopentyl bromide with sodium cyanide to give cyclopentyl cyanide... 

The alternative combination cyclopentyl bromide and sodium ethoxide is not appropriate because elimination will be the major reaction... 

A solution of 1.5 grams of 17a-ethynyl estradiol in 50 cc of absolute ethanol is added slowly to a mixture of 3 grams of cyclopentyl bromide and 2 grams of potassium carbonate. This mixture is heated to reflux and stirred for 3 hours, then filtered. Most of the alcohol is eliminated by distillation and the resulting solution diluted with water, and cooled in an ice-bath. The product which precipitates Is collected by filtration, washed and dried. After recrystallization from methanol the 3-cyclopentyl ether of 17a-ethynyl estradiol shows a melting point of 107° to 108°C. 

Cyclopentamine HCI Cyclopentolate HCI Cyclopentyl bromide Ketamine HCI Quinestrol... 

Cyclopentanepropanoic acid, c405 Cyclopentene oxide, e42 Cyclopentyl bromide, b313 Cyclopentyl chloride, c93 Cyclopropyl bromide, b314 Cyclopropyl cyanide, c407... 

Cydopentanol, 255 Cyclopentanone, 336, 340, 489, 493 Cyclopentyl bromide, 277 Cydopentyl chloride, 276 Cyclopentyl iodide, 285... 

Towards the cyclopentyl homologue, a solution of 2,5-dimethoxythiophenol and cyclopentyl bromide in DMSO containing anhydrous potassium carbonate was stirred for several hours at room temperature and yielded 2,5-dimethoxyphenyl cyclopentyl sulfide as a white oil that boiled at 135-145 °C at 0.3 mm/Hg. This was brought to react with amixtureofphosphorusoxychlorideand N-methylformanilide producing 2,5-dimethoxy-4-(cyclopentylthio)benzaldehyde as yellow crystals from MeOH. This will some day be converted to the nitrostyrene and then reduced to 2,5-dimethoxy-4-cyclopentylthiophenethylamine hydrochloride, 2C-T-23. 

The cyclopentyl nucleophile, which should be an organocuprate to ensure Michael addition, could be produced from cyclopentyl bromide. The synthetic sequence consistent with die retrosynthetic analysis turns out to be a rather simple synthesis of what at first sight is a more difficult molecule. 

Cyclopentyl bromide, b263 Cyclopentyl chloride, c79 Cyclopropyl bromide, b264 Cyclopropyl cyanide, c365... 

Cognate preparation. Nitrocycbpentane. Use cyclopentyl bromide (22.0 g, 0.15mol), sodium nitrite (18g, 0.26mol) and 100ml of dimethyl sulphoxide allow the reaction mixture to stir at 15 °C for 3 hours. The product (9.9 g, 58%), b.p. 62°C/8mmHg, no1 1.4538, was isolated as above. 

Tetrazolyl)-4//-pyrido[l,2-a]pyrimidin-4-ones 441 were alkylated with alkyl iodides, alkyl bromides, triethyl phosphate, cyclopentyl bromide, allyl bromide, propargyl bromide, benzyl chlorides, ethyl bromoace-tate, and methyl chloroformate in dimethylformamide in the presence of potassium carbonate at 80-90°C to give a mixture of 3-(l-substituted 5-tetrazolyl)- and 3-(2-substituted 5-tetrazolyl)-4//-pyrido[l,2-u]pyrimidin-... 

An analogous sequence involving cyclopentyl bromide could be used. 

Once cyclopentyl bromide has been prepared, it is converted to cyclopentyl cyanide by nucleophilic substitution, as shown in part (a). 

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