反应详情

Monomers of Formula IV, wherein —Ar1(Ey)a- is Formula XXXV, XXXVI, XXXVII, or XXXVIII may be made as illustrated by the preparation of a 2,8-dibromo-6,12-dihydroindeno[1,2-b]fluorene using the process of Reaction Scheme X. In step (1), Suzuki coupling of 2-(2,5-dimethylphenyl)-4,4,5,5-tetramethyl [1,3,2]dioxaborolane with commercially available 2-bromo-9-fluorenone provides 2-(2,5-dimethylphenyl)fluoren-9-one. Commercially available 2-bromo-p-xylene is converted to 2-(2,5-dimethylphenyl)-4,4,5,5-tetramethyl[1,3,2]dioxaborolane by treatment with butyl lithium and reaction of the lithiated intermediate with 2-isopropoxy-4,4,5,5-tetramethyl[1,3,2]dioxaborolane. In step (2), 2-(2,5-dimethylphenyl)fluoren-9-one can be converted to 2-bromo-7-(4-bromo-2,5-dimethylphenyl)fluoren-9-one with bromine in chloroform at 0° C. Regiospecific bromination at the 4′-position of the phenyl ring is directed by the 5′-methyl and fluorene substituents. In step (3), 2-bromo-7-(4-bromo-2,5-dimethylphenyl)fluoren-9-one can undergo potassium permanganate oxidation to provide 2-bromo-5-(7-bromo-9-oxo-9H-fluoren-2-yl)-terephthalic acid. Ring closure, in step-(4), to 2,8-dibromo-6,12-dioxa-6,12-dihydroindeno[1,2-b]fluorene-3-carboxylic acid is effected by treatment with sulfuric acid. Reduction of 2,8-dibromo-6,12-dioxa-6,12-dihydroindeno[1,2-b]fluorene-3-carboxylic acid, in step (5), with red phosphorus provides 2,8-dibromo-6,12-dihydroindeno[1,2-b]fluorene-3-carboxylic acid. In step (6), alkylated by reaction with butyl lithium followed by an R3-halide or by phase transfer methods utilizing, for example, benzyltriethylammonium chloride in dimethylsulfoxide, followed by 50% aqueous sodium hydroxide and then R3—Br provides the indeno[1,2-b]fluorene derivative of Formula CXLIX. Treatment of the indeno[1,2-b]fluorene of Formula CXLIX with thionyl chloride gives the reactive acyl chloride intermediate of Formula CL. The oxadiazole, thiadiazole, or triazole may be formed at the acyl chloride group of the acyl chloride intermediate via a benzhydrazide intermediate as in Reaction Schemes III–V or by direct coupling with a tetrazole as in Reaction Scheme II. In step (8), for example, the oxadiazole of Formula CLI is provided by reaction of the acyl chloride intermediate of Formula CL with 5-(4-octyloxyphenyl)-1H-tetrazole as in Reaction Scheme II.