Thermotropic copolyamides from triethylene glycol bis(4-carboxyphenyl) ether ando-tolidine modified by kinking monomers

Kim, Ji‐Hwan; Kimura, Mitsuo; Higashi, Fukuji

doi:10.1002/(sici)1099-0518(19990201)37:3<363::aid-pola14>3.0.co;2-a

Cited by 2 publications

(1 citation statement)

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“…Simple aromatic hydrocarbons and methyl substituted derivatives have featured as substrates in both earlier and more recent studies of the reaction including benzenes [6,7,17-19], biphenyls and fluorene [11,13,20], naphthalenes [21-23], anthracenes [14,24,25], phenanthrenes [12,26], pyrenes [27], and chrysenes [28] and as a part of our continuing interest in Friedel-Crafts acetylations [11,13,21,28-31], we now report details of the acetylation of 3,3′-dimethylbiphenyl (3,3′-dmbp). Compounds and materials derived from this building block are of particular interest in the field of molecular liquid crystals [31], polymers [32,33] and metal-complexes [34]. …”

Section: Resultsmentioning

confidence: 99%

A reactivity-selectivity study of the Friedel-Crafts acetylation of 3,3′-dimethylbiphenyl and the oxidation of the acetyl derivatives

Titinchi

Kamounah

Abbo

et al. 2012

Chemistry Central Journal

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BackgroundFriedel-Crafts acetylation is an important route to aromatic ketones, in research laboratories and in industry. The acetyl derivatives of 3,3′-dimethylbiphenyl (3,3′-dmbp) have applications in the field of liquid crystals and polymers and may be oxidized to the dicarboxylic acids and derivatives that are of interest in cancer treatment.FindingsThe effect of solvent and temperature on the selectivity of monoacetylation of 3,3’-dmbp by the Perrier addition procedure was studied using stoichiometric amounts of reagents. 4-Ac-3,3′-dmbp was formed almost quantitatively in boiling 1,2-dichloroethane and this is almost twice the yield hitherto reported. Using instead a molar ratio of substrate:AcCl:AlCl3 equal to 1:4:4 or 1:6:6 in boiling 1,2-dichloroethane, acetylation afforded 4,4′- and 4,6′-diacetyl-3,3′-dmbp in a total yield close to 100%. The acetyl derivatives were subsequently converted to the carboxylic acids by hypochlorite oxidation. The relative stabilities of the isomeric products and the corresponding σ-complexes were studied by DFT calculations and the data indicated that mono- and diacetylation followed different mechanisms.ConclusionsFriedel-Crafts acetylation of 3,3′-dmbp using the Perrier addition procedure in boiling 1,2-dichloroethane was found to be superior to other recipes. The discrimination against the 6-acetyl derivative during monoacetylation seems to reflect a mechanism including an AcCl:AlCl3 complex or larger agglomerates as the electrophile, whereas the less selective diacetylations of the deactivated 4-Ac-3,3′-dmbp are suggested to include the acetyl cation as the electrophile. The DFT data also showed that complexation of intermediates and products with AlCl3 does not seem to be important in determining the mechanism.

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