Acetyl bromide synthesis

Borgman, R. J., Smith, R. V., Keiser, J. E. The acetylation of apo-morphine. An improved method for the selective preparation of diacetylapomorphine utilizing trifluoroacetic acid/acetyl bromide. Synthesis 1975, 249-250. 

Interchange of halogen is a means of synthesis of certain acyl halides which cannot be conveniently prepared by other methods. Acetyl fluoride is made from acetyl chloride and sodium hydrogen fluoride in acetic anhydride solution." By passing a stream of hydrogen bromide through oxalyl chloride an 85% yield of oxalyl bromide, (COBr), is obtained. The bromide cannot be made by the action of phosphorus pentabromide on oxalic acid. The method has also been applied to the preparation of acetyl bromide and iodide and other acyl iodides. ... 

Oxirans. - The synthesis of l,2-anhydro-3,4-di-0-benzyl-6-deoxy-a-D-glucopyranose and its conformational analysis have been reported. A range of epoxides have been prepared by base treatment of bromohydrins, which were made by reaction of hydrogen bromide with aldonolactones. A one-pot conversion of vicinal diols into epoxides employs halohydrin ester intermediates generated from cyclic orthoacetates and either acetyl bromide or trimethylsilyl chloride. Levoglucosenone has been transformed into l,6 3,4-dianhydro-p-D-talopyranose by way of a trn/w-iodo-acetoxylation of the alkene moiety... 

The foregoing transacylation method was later employed in the synthesis of other highly bioactive cephamycin derivatives including CS1170 (Nakao et al., 1976 Shimizu et al., 1976). N-BOC-protected esters (425) were diacylated (426) with chloroacetyl chloride (or faster with bromo-acetyl bromide) and bis(trimethylsilyl)trifluoroacetamide in methylene chloride (40°C). Trifluoroacetic acid treatment afforded the transacylated acid (427). Nucleophilic substitution of 427 by a variety of heterocyclic mercapto compounds in the presence of 2 equiv of sodium hydroxide gave a series of semisynthetic cephamycins for which antibacterial data were given vide infra). 

Scheme 2.20 Synthesis of quinoxalinones from 2-oxo-2-aryl acetyl bromides 219...

Figure 6.31 Use of bromofl- C]acetyl bromide in C-acylations applied to the synthesis of 3-phenyl[3- C]indole derivatives...

The Al-acylation of lithiated (25)- or (2/f)-bomane-10,2-sultam 1921 (Figure 6.34) with bromo[ " C]acetyl bromide illustrates the ready accessibility of bromo[ C]acetyl (25)- or (2R)-bomane-10,2-sultam ((25) or (2R)-[ C]BABS, 93). Compound 93 is a versatile building block for the synthesis of e.p. carbon-14-labeled a- and /3-amino acids,... 

The formation of cyanohydrins using CyanotrimethylsUane and Isoselenocyanatotrimethylsilane has been effectively catalyzed by ZnCl2 (eq 30),as has Strecker amino acid synthesis via the treatment of imines with Me3SiCN/ZnCl2. The combination of carbonyl compounds with Acetyl Chloride or Acetyl Bromide may be promoted by ZnCb to afford protected vicinal halohydrins (eq... 

A great many organic quaternary bases can inhibit the action of acetyl choline in organ systems activated by that neurotransmitter and thus possess anticholinergic-antispasmodic activity. One such agent is methantheline bromide (4), used in the treatment of peptic ulcer and as an antispasmodic agent in intestinal disorders. Its synthesis Involves Friedel-Crafts cyclization of o-... 

Because synthesis of l-(2-deoxy-2-fluoro-)S-D-arabinofuranosyl)cytosine (744, FAC), an elementary arabino type of nucleoside having a growth-inhibitory effect against L 1210 leukemia in mice, through direct introduction of a fluorine atom in the 2 - up (arabino) position was difficult, compound 744 was prepared by condensation of trimethylsilylated A -acetylcytosine with 3-0-acetyl-5-(7-benzoyl-2-deoxy-2-fluoro-D-arabin-ofuranosyl bromide (742), which had been prepared by periodate oxidation of 6-0-benzoyl-3-deoxy-3-fluoro-D-glucofuranose (741). Similar condensa-... 

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