Description
Cyclopropyl bromide is also named as Bromocyclopropane. It is used in organic synthesis, for instance, for the formation of a Grignard Reagent, cyclopropyllithium. It is also used as an intermediate in the manufacture of pharmaceutical and agrochemical products.
Chemical Properties
Light yellow to clear colourless liquid, boiling point 67-69°C, refractive index (nD20) 1.4605, density (d420) 1.5120, flash point -6°C.
Preparation
Bromocyclopropane has been prepared by the Hunsdiecker reaction by adding silver cyclopropanecarboxylate to bromine in dichlorodifluoromethane at ?29° (53% yield) or in tetrachloroethane at ?20° to ?25° (15–20% yield). Decomposition of the peroxide of cyclopropanecarboxylic acid in the presence of carbon tetrabromide gave bromocyclopropane in 43% yield. An attempt to prepare the bromide via the von Braun reaction was unsuccessful. Ten percent yields are reported for the photobromination of cyclopropane and the photochemical rearrangement of allyl bromide. Treatment of 1,1,3-tribromopropane with methyllithium prepared from methyl bromide furnishes a 60–65% yield of bromocyclopropane.
Application
Bromocyclopropane have anti-angiogenic effects that inhibits the growth of new blood vessels by interfering with the production of prostaglandins and nitric oxide, which are important for the formation of new blood vessels. Bromocyclopropane binds to cyclopropyl and hydrochloric acid, forming a hydrogen bond. It also forms a hydrogen bond with fatty acids and an a-type hydroxyl group.
References
Science of Synthesis: Houben-Weyl Methods of Molecular Transformation Vol. 7: Compounds of Group 13 and 2 (Al, Ga, In, Tl, Be…Ba), 2007, ISBN: 9783131484819
D. Seyferth, H. M. Cohen, The Stability of Cyclopropyllithium in diethyl ether and in tetrahydrofuran, Journal of Organometallic Chemistry, 1963, vol. 1, pp. 15-21
“Formal Nucleophilic Substitution of Bromocyclopropanes with Azoles”, Ryabchuk, P.; Rubina, M.; Xu, J.; Rubin, M. Org. Lett. 2012, 14, 1752.
“Formal Substitution of Bromocyclopropanes with Nitrogen Nucleophiles”, Banning, J. E.; Gentillon, J.; Ryabchuk, P. G.; Prosser, A. R.; Rogers, A.; Edwards, A.; Holtzen, A.; Babkov, I.; Rubina, M.; Rubin, M. J. Org. Chem., 2013, 78, 7601.
