M- Bromobenzoic acid

Figure 6 Chromatogram for separation of positional isomers of bromobenzoic acid in strong anion-exchange CEC. Experimental conditions mobile phase, 50% acetonitrile in 10 mM phosphate buffer pH 2.2. Peaks (1) p-bromobenzoic acid (pKa 4.00) (2) m-bromobenzoic acid (pKa 3.81) (3) o-bromobenzoic acid (pKa 2.85). (Reprinted from Ref. 41, with permission.)...

In Richter reaction m-bromobenzoic acid may be obtained by reactini potassium cyanide with p-nitrobromobenzene. The original mechanism of tht... 

To make m-bromobenzoic acid from toluene one should first oxidize the methyl group to a carboxylic acid, which is a meta director, and then introduce the bromine. If the bromine is introduced first, it will go ortho and para since the methyl group is an ortho/para director. 

Sulphone, 202 o-Fluobenzoio acid, 127 m-Fluobenzoic acid, 124 p-Fluobenzoic acid, 186 o-Chlorobenzoic acid, 141 m-Chlorobenzoic acid, 158 p-Chlorobenzoic acid, 242 o-Bromobenzoic acid, 148 m-Bromobenzoic acid, 155 p-Bromobenzoic acid, 251 o-Iodobenzoic acid, 162 m-Todobenzoic acid, 186 p-Iodobenzoic acid, 269 S Benzyl-wo-thiuronium picrate, 188 Benzaldehyde plienyl-hydrazone, 156 Benzoic acid, 121... 

Prepare a second Hammett plot using the values of the apparent rate constant for the catalytic reaction. Use the Hammett relation to estimate the apparent rate constant for esterification of m-bromobenzoic acid over AIPO4 and compare this value with the experimental value of (7.6 0.6) X 10" [mol/(atm-g-s)]. Consider two ways to generate the equation of the line that best represents the data. 

A mixture of m-bromobenzoic acid and tetrahydrofuran added at 65° under Ng during 3-4 min. to a complex reducing agent prepared from NaH, rerr-amyl alcohol, and Ni-acetate in tetrahydrofuran, and stirred 1-2 hrs. at the same temp. 

PROBLEM 4.15 Compare the intermediate benzenonium ions for ortho, meta and para bromination of benzoic acid, and explain why the main product is m-bromobenzoic acid. 

However, m-bromobenzoic acid can be converted into benzoic acid in 90% yield by using water soluble tris[3-(2-methoxyethoxy)propyl] stannane in presence of 4,4 -azobis (4-cyanovaleric acid) (ACVA) or sunlamp as initiator in aqueous NaHC03- Above debromination can also be effected by using [bis(potassiumpropanoate)n (hydroxystannate), which in presence of NaBH and ACVA affords reductions and free radical cyclisation of aryl and alkenyl bromides (Scheme 110). 

Reactions with sodium tetraphenylborate showed very high catalytic efficiency. So, the reaction of m-bromobenzoic acid gives a quantitative yield of phenylated product even if the initial load of PdCl2 is as low as 0.0004 mol %, which corresponds to a turnover number of 250,000 (Scheme 44). 

Bromophenyl)-5-bromobenzothiazole. A mixture of 2-amino-4-bromomercaptobenzene hydrochloride (20g, 83 mmole) and polyphos-phoric acid (274g) was heated at 70 C until dehydrochlorination was complete. To the mixture was then added sulfolane (109g) and m-bromobenzoic acid (22g, 110 mmole). The mixture was heated at 90 C for 3 h, at 145 C for 18 h, at 190 C for 1 h, and finally, at 200 C for 1 h. The reaction mixture was allowed to cool to room... 

Two isomeric acetylenic benzothiazole monomers, 2-(3-ethynyl-phenyl)-5-ethynylbenzothiazole (3) and 2-(3-ethynylphenyl)-6-ethynyl-benzothiazole (4) were prepared according to the general reaction scheme shown below. The synthesis of the benzothiazole heterocyclic structure was carried out by the condensation of m-bromobenzoic acid with isomeric bromo-substituted o-aminomercaptobenzenes in poly-phosphoric acid (PPA). The bis-bromobenzothiazoles were converted to the acetylene systems by the reaction with 2-methyl-3-but3m-2-ol and subsequent displacement of acetone with base. The bromo displacement reaction utilized a catalyst composed of triphenylphosphine, (bis-triphenylphosphine)palladium dichloride and cuprous iodide. 

---