Bromoacetamide, preparation

The Q. j-unsaturated ester and amide 942 is prepared by the Pd-catalyzed Wittig-type reaction of the bromoacetate or bromoacetamide 941 with aldehydes and BU(Asf785],... 

Bromine monofluoride [13863-59-7], BrF, can be prepared by the direct reaction of Br2 and F2, but because it readily disproportionates it has never been prepared in pure form (57). However, BrF can be prepared in situ by the reaction of Br2 with AgF in benzene (58) or by the reaction of A/-bromoacetamide and HF in ether (59). BrF adds to simple alkenes at room temperature to give products of trans-addition. Bromine trifluoride [7787-71-5], BrF, can be formed from gaseous fluorine and Hquid bromine (60). Bromine pentafluoride [7789-30-2], BrF, is formed from the reaction of BrF vapor with gaseous fluorine at 200°C (60). The tri- and pentafluorides are commercially available. As strong fluorinating agents they are useful in... 

Addition of fluorohalides to double bonds preparation of 9a-bromo-ll/3-fluoro-17q , 21-dihydroxypregn-4-ene-3, 20-dione 21-acetate by reaction with N-bromoacetamide-hy drogen fluoride, 458... 

The method of Fried and Sabo for the in situ preparation of hypobromous acid from A-bromoacetamide (or A-bromosuccinimide) in aqueous dioxane or acetone containing perchloric acid is commonly used, e.g., (81) (82). 

Vicinal iodo carboxylates may also be prepared from the reaction of olefins either with iodine and potassium iodate in acetic acid/ or with N-iodosuccinimide and a carboxylic acid in chloroform. " A number of new procedures for effecting the hydroxylation or acyloxylation of olefins in a manner similar to the Prevost or Woodward-Prevost reactions include the following iodo acetoxylation with iodine and potassium chlorate in acetic acid followed by acetolysis with potassium acetate reaction with iV-bromoacetamide and silver acetate in acetic acid reaction with thallium(III) acetate in acetic acid and reaction with iodine tris(trifluoroacetate) in pentane. ... 

A similar but simpler 4-imino-hexahydropyrrolo[l,2-tf]pyrazin-l(277)-one 311 was prepared starting from the product obtained by nucleophilic substitution of a primary amine to the bromoacetamide of the L-prolylnitrile 310 (Scheme 40). The cyclization occurred directly in basic medium by refluxing for 96 h in EtOAc. This compound showed a potent activity as an orally bioavailable dipeptidyl peptidase IV inhibitor with anti-hyperglycemic properties <2003JME2774>. 

Water-insoluble amines can be used as base and a second phase at the same time. A series of anthranilic acids was prepared by carbonylation of 0-bromoacetamides at 100-130 °C with [PdCl2(PPh3)l as catalyst (Scheme 5.8). Isolated yields were as high as 85 % (R = H, R" = Pr) [30]. 

A/-[3-(2-[ F]fluoropyridin-3-yloxy)-propyl]-2-bromoacetamide (p F]FPyBrA) was recently prepared by nucleophilic / eferoaromatic radiofluorination using a three-step radiochemical pathway and obtained in 20% overall non-decay-corrected yield in less than 85 min. In this reagent, the pyridinyl moiety carries the radioactive fluorine and the 2-bromoacetamide function ensures the alkylation of phosphorothioate monoester groups at the 3 - or 5 -end of a single-stranded oligonucleotide [18],... 

The addition of bromine monofluoride to alkenes using equimolar quantities of /V-bro-moamides in excess anhydrous hydrogen fluoride gives the expected l-bromo-2-fluoroalkanes and small amounts (3-8 %) of isomeric 2-bromo-l-fluoroalkanes.29 1-Bromo-2-fluoroheptane can be prepared in 60-77% yield from hept-l-cnc, /V-bromoacetamide and hydrogen fluoride in diethyl ether at — 78"C.30 The bromofluorination of methyl methacrylate (1) with 1,3-di-bromo-5.5-dimethylhydantoin (DBH) and liquid hydrogen fluoride exemplifies this procedure.31... 

Some of the nitrogen sources mentioned above (e.g., Chloramine-T and N-bromoacetamide) are commercially available. In other cases, the chloramine salts have to be prepared in situ by treating the amide with ferf-butyl hypochlorite [32] and sodium hydroxide [15]. It has been found that the unstable tert-... 

N-bromoacetamide has been prepared from acetamide and bromine in the presence of potassium hydroxide,2,3 zinc oxide,4 or calcium carbonate.4... 

The simultaneous addition of fluorine and bromine to alkynes can be carried out by the use of bromine fluoride, prepared directly from the corresponding elements, the hydrogen fluoride/IV-bromoacetamide system (HF/AcNHBr) or the hydrogen fluoride/pyridine complex in combination with either (V-bromosuccinimide or 1,3-dibromo-5.5-dimethylhydanloin (DBH). Examples arc listed in Tabic 44. 

Oxiranes are usually prepared from halohydrins. A general method of obtaining chloroalcohols from olefins is by the addition of hypochlorous acid formed in situ form -chloramides or fert-butyl hypochlorite. Bromoalcohols are produced from alkenes with Ai-bromosuccinimide or iV-bromoacetamide, while iodoalcohols are prepared with iodine in the presence of oxidants (iodic acid, oxygen, and nitrite). 

Dehydration Alumina (see also Dihydropyrane, preparation). Boric acid. Boron triSuoride. N-Bromoacetamide-Pyridine-SOj. Dicyclohexylcarbodiimide. Diketene. Dimethylform-amide-Thionyl chloride. Dimethyl sulfoxide. Ethylene chlorophosphite. Florisil. Girard s reagent. Hydrobromic acid. Iodine. Mesyl chloride-Sulfur dioxide. Methyl chlorosulfite. Methylketene diethylacetal. Naphthalene-d-sulfonic acid. Oxalic acid. Phenyl isocyanate. Phosgene. Phosphorus pentoxide. Phosphoryl chloride. Phthalic anhydride. Potassium bisulfate. Pyridine. Thionyi chloride. Thoria. p-Toluenesulfonic acid. p-Toluenesulfonyl chloride. Triphenylphosphine dibromide. 

The preparation of 2-substituted l,4-benzodiazepin-3-ones by highly diastereoselective alkylation (with n-BuLi as the base in THF) of the l,4-benzodiazepin-3-one 127 with an N-based chiral auxiliary has been described <05EJ01590>. The precursor 126 was assembled in a multi-step synthesis starting from o-nitrobenzaldehyde and proceeding via the chiral amino alcohol 122 to 123, 124, 125, and the bromoacetamide 126. Base-induced intramolecular nucleophihc displacement in 126 then gave 127 in fair yield. 

The preparation and analysis of TV-bromoacetamide is described in Organic Syntheses 292 for A-bromosuccinimide see page 148. 

Functionalization of pyridines from the corresponding bromo substrates has been achieved by use of Reformatsky reagents and a microwave-accelerated reaction procedure [65]. This approach utilizes Pd(0)-catalyzed a-arylation of esters and amides (Scheme 10.29). The Reformatsky reagent was prepared by microwave irradiation of tert-butyl bromoacetate or dibenzyl bromoacetamide with Zn in THF for 5 min at 100 °C. 

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