11- Bromobenzoate

With 7-bromobenzo[a]cyclohept-2-ene-l-one in alcohol solution, the 9,10-dihydro-8H-benzo-4,5-cyclohepta-[d]-thiazol-2-ylhydrazine (143) was obtained in 46% yield (Scheme 69) (679, 688, 689). 

Terephthalic acid has been obtained from a great many /)-disubstituted derivatives of benzene or cyclohexane by oxidation with permanganate, chromic acid, or nitric acid. The following routes appear to have preparative value from />-toluic acid, />-methylacetophenone,2 or dihydro-/)-tolualdehyde by oxidation with permanganate from f>-cymene by oxidation with sodium dichromate and sulfuric acid from />-dibromobenzene or from /i-chloro- or -bromobenzoic acid by heating at 250° with potassium and cuprous cyanides and from />-dibromo-benzene, butyllithium, and carbon dioxide. ... 

Five to ten grams of crude />-bromobenzoic acid can be obtained by acidifying the solution left in the distilling flask. 

Thirty grams of purified 2,4-dihydroxy-5-bromobenzoic acid is refluxed for twenty-four hours with 375 cc. of water, and the resulting solution is filtered, cooled, and extracted with a 400-cc. and a 200-cc. portion of ether. The ether is removed by evaporation, and the 4-bromoresorcinol is dried on a steam bath. The yield of product melting at 100-102° (Note 2) is 22-22.5 g. (90-92 per cent of the theoretical amount). 

Reaetion of several 3-bromobenzoic acids with excess LDA, followed by addition of a benzyl cyanide, gave the product mixtures shown. Suggest a mechanism for the formation of each of these products. 

Cyclocondensation of 2-chloronicotinic acid with 2-amino-5-iodobenzoic acid and methyl 2-amino-4-bromobenzoate in boiling EtOH in the presence of cone. HCl for 18 h gave the 2-iodo and 3-bromo derivatives of 11-0X0-1 l/f-pyrido[2,l-6]quinazoline-6-carboxylic acid (98MIP1, 98MIP2, 99USP5908840, 99USP5914327). 

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