From Dibromoacetic Acid

A readily available formyl ester equivalent is ethyl dibromo- or dichloroacetate, or the free acid. For example xanthopterin, 2-aminopteridine-4,6(3/T,5/T)-dione, can be made in 65% yield via the intermediate dibromoacetamino compound, from 2,5,6-triaminopyrimidin-4(3//)-one and dibromoacetic acid.82... 

The tendency for -bromination is so strong that treating fatty acids with bromine in presence of halogen carriers (S, P, or I2) in a bomb tube leads to a ,a -dibromo acids dibromoacetic acid, for instance, is obtained from glacial acetic acid and bromine in the presence of sulfur at 150°.568... 

A methodically related transformation, the copper(Il)-mediated transfer of a cyano(ethoxycar-bonyl)methylene unit from ethyl cyanoacetate to alkenes, is presented in Section I.2.I.2.4.2.9. The copper-mediated synthesis of cyclopropyl ketones from a,a-dibromo ketones and alkenes seems to be of very limited scope and even less efficient than the corresponding synthesis of cyclopropanecarboxylic acids from o ,a-dibromoacetates (vide supra). The reaction (toluene, 100°C, 93 h) of cyclooctene (4.0 mmol), dibromomethyl phenyl ketone (8.0mmol), and commercial grade copper powder (18 mmol) activated with iodine (0.2 mmol) gave exy-9-benzoyl-bicyclo[6.1.0]nonane (7, 12%) and (2-oxo-2-phenylethyl)cyclooct-l-ene (8, 3%). ° A similar treatment of styrene gave l-benzoyl-2-phenylcyclopropane in only 2% yield [ratio (cisjtrans) 1 l.b]. " ... 

Figure 14 Separation of haloacetic acids and inorganic anions. Column Cryptand A15(x (150mm x 3mm) eluent gradient —8 to 3min, lOmM NaOH t = 3min, lOmM LiOH. Monochloro-cacetic (MCA), monobromoacetic (MBA), dichloroacetic (DCA), bromochloroacetic (BCA), dibromoacetic (DBA), trichloroacetic (TCA), monobromodichloroacetic (MBDCA), monochlorodibro-moacetic (MCDBA), and tribromoacetic (TBA) acids. (Reproduced from Ref. 64. Elsevier, 2008.)...

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