Mayer, Ursula Jula Hanna (1961)
Optical studies of 2-t-butyl-2-substituted biphenyls.
Full text access: Open
Several 2-t-butyl-2'-substituted biphenyls have been prepared and resolved. The synthesis of these compounds was effected by heating with copper bronze a mixture of o-iodo-t-butylbenzene (or a derivative) and the appropriately substituted halogeno-benzene (or naphthalene) (Ullmann reaction). Large quantities of o-iodo-t-butylbenzene and methyl (or ethyl) 3-iodo-4-t-butylbenzoate have therefore been prepared. 6,6'-Di-t-butylbiphenyl-3"3lidicarboxylic acid was resolved through the brucine salt, and optically active 2,2'-di-t-butylbiphenyl has been obtained by decarboxylation of the optically active acid. 2',6 -Di-t-butylbiphenyl-3-carboxylic acid has been resolved through its strychnine salt and found to show high optical stability.An unsuccessful attempt was made to prepare 2,-nitro-6-t-butylbiphenyl-3-carboxylic acid, however, the synthesis of 2'-t-butyl-6-nitrobiphenyl-4-carboxylic acid succeeded and it was found that its strychnine salt underwent second-order asymmetric transformation in ethanol, and racemised in boiling chloroform solution. Racemisationof the optically active acid was studied at several temperatures between 51° and 75° and from the rates of racemisation the energy of activation was found to be 25.4 kcal.mole-1.Methyl 8-(2'-t-butylphenyl)-l-naphthoate was prepared by heating equimolecular proportions of0-iodo-t-butylbenzene and methyl 8-bromo-1-naphthoate.The acid obtained by hydrolysis of this ester was resolved through its strychnine salt, and racemisation of the optically active acid was studied. An attempt to prepare (2'-t-butylphenyl)-1-naphthalene from 8-(2'-t-butylphenyl)1-naphthoic acid by the Schmidt reaction resulted in the formation of the cyclisation product, 7-oxo-11-t-butylbenz[d e]anthracene. The benzanthracene obtained from the optically active acid was inactive.
This is a Accepted version
This version's date is:
is not peer reviewed
Deposited by () on
in Royal Holloway Research Online.Last modified on 31-Jan-2017
Digitised in partnership with ProQuest, 2015-2016.
Institution: University of London, Bedford College (United Kingdom).