Bromo acetyl bromide

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). 

The preparation reported here is based on the method of Christie and Rapoport.4 9-Bromo-9-phenylfluorene has also been prepared by a light-initiated reaction of bromine and 9-phenylfluorene in carbon disulfide,2 by addition of phenylmagnesium bromide to fluorene36 followed by treatment with acetyl bromide,5 and by treatment of 9-phenylfluorene with N-bromosuccinimide.6... 

Hydrogen bromide, trimethylsilyl bromide and acetyl bromide have all been proven to be suitable bromide transfer agents [e.g. 12, 13]. Tetra-n-butylammonium salts catalyse the interconversion of dichloroalkanes into bromochloroalkanes and chloroiodoalkanes upon reaction with an excess of bromo- and iodobutane, respectively [14]. Similarly, mixed bromochloromethanes are obtained from the reaction of dibromochloromethane with benzyltriethylammonium chloride under basic conditions [15]. 

Table 2 Polymerization rates (in 10 L mol s ) of CROP of EtOx with different initiators at various temperatures - acetyl chloride (AcCl), acetyl bromide (AcBr), acetyl iodide (Acl), and 2-bromo-2-methylpropanoyl bromide (BrEB/B)...

Hydroxy-3-nitro-5,6-diphenylpyrazine with acetyl bromide, iodine bromide, or dry hydrogen bromide in dry dioxane gave 2-bromo-3-hydroxy-5,6-diphenyl-... 

Cleavage with acetyl bromide (acetobromolysis) afforded the 6,8-bromo-3a-acetoxytropane (XLVII) together with some 3jS-bromo-6a-acetoxytropane (LXIX). 

We have already seen how cyclic sulfates such as 123 can be converted into amino alcohols that might have been made by amino hydroxylation. The conversion of 1,2-diols, made by the AD reaction, into epoxides has been very widely used. A combination of acetyl bromide and an orthoester gives a bromo-acetate via an oxonium ion 182. The ion is formed with retention, bromide opens it with inversion at the benzylic centre, and epoxidation in base inverts it again. The net result is retention.39... 

Interaction between a-methyl-tetrahydrofuran and acetyl bromide yields bromo derivative which on treatment with isopropyl amine forms a corresponding amine derivative. This on treatment with aqueous NaOH and thionyl bromide gives the side chain. 

The addition of HBr to an alkyne can be facilitated by using acetyl bromide (CHsCOBr) and alumina instead of aqueous HBr. Acetyl bromide acts as an HBr precursor by reacting with the alumina to generate HBr. For example, 1-heptyne can be converted to 2-bromo-l-heptene in good yield using this method ... 

Startg. m. stirred 12 hrs. at room temp, with acetyl chloride in tetrahydrofuran -> product. Y 90%. Also bromo-analog with acetyl bromide s. Y. Fujisawa and O. Mitsunobu, Chem. Commun. 1973, 201 s. a. R. Marumoto and M. Honjo, Chem. Pharm. Bull. 22, 128 (1974). 

A mixture of 6-amino-6-deoxy-D-glucose hydrochloride and acetyl bromide stored 74 hrs. in a brown flask with frequent shaking 2,3,4-tri-O-acetyl-6-amino-a-l-bromo-6-deoxy-D-glycopyranose hydrobromide. Y 96.3%. 3-Amino analog in 3 hrs. s. Y. Ito, S. Koto, and S. Umezawa, Bull. Chem. Soc. Japan 35, 1618 (1962). 

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,... 

Figure 6.34 Use of bromo[ C]acetyl bromide in N-acylation of amides, imides and sulfonamides preparation of (2S-N-bromo[ " C]acetyl)bornane-10,2-sultam...

Both antipodes are obtained in >70% yield upon heating sodium [1- C]- and [1,2- 2]-acetate with a mixture of Br2 and PBra followed by vacuum transfer of the resulting bromo[ C ]acetyl bromide into a suspension of the lithiated auxiliary. The requisite... 

Dehydrochlorination of bis(tnfluoromethylthio)acetyl chloride with calcium oxide gives bis(trifluoromethylthio)ketene [5] (equation 6) Elimination of hydrogen chloride or hydrogen bromide by means of tetrabutylammonium or potassium fluoride from vinylic chlorides or bromides leads to acetylenes or allenes [6 (equation 7) Addition of dicyclohexyl-18-crown-6 ether raises the yields of potassium fluoride-promoted elimination of hydrogen bromide from (Z)-P-bromo-p-ni-trostyrene in acetonitrile from 0 to 53-71 % In dimethyl formamide, yields increase from 28-35% to 58-68%... 

Nucleophilic displacement of bromide from 5-acetyl-10-bromo-5//-dibenz[7>,/]azepine (41) by alkoxide,132 and by cyanide ion in dimethylformamide,212 has been noted. However, replacement of bromide by cycloalkylamines (e.g., piperidine) to give the 10-cycloalkylamino derivatives. e.g. 44, is best accomplished in the presence of potassium ferf-butoxide, a result which suggests that the aminodebromination proceeds via an elimination-addition (EA) pathway involving an azepyne intermediate 43 (see Section 3.2.1.5.7.) rather than by the more usual addition-elimination (AF.) mechanism.118... 

Methyl (2,3,4-tri-Oacetyl-a-D-glucopyranosyl)uronate bromide not methyl 2,3,4-tri-0-acetyl-1-bromo-1-deoxy-a-D-glucopyranuronate... 

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