CCXLII.—Studies in the diphenyl series. Part II. The dinitrobenzidines: a new form of isomerism

Abstract

CCXLII.-Studies in the Diphenyl Series. Part 11. The Dinitrobenxidines : a New Form of Isomerism. 3 3 7 JOHN CANNEZL CAIN, ALBERT COULTHARD, and FRANCES MARY GORE MICELETHWAIT. IN 1872 Strakosch (Ber., 5, 236) nitrated diacetylbenzidine and obtained a dinitrobenzidine, which was shown very conclusively by Brunner and Witt (Ber., 1887,20, 1023) to contain the nitro-groups in the ortho-position with respect t o the amino-groups.

1,1′-Biisoquinolines—Neglected Ligands in the Heterocyclic Diimine Family That Provoke Stereochemical Reflections

“…Atropisomerism is commonly observed in compounds in which aromatic rings are connected by a single C–C bond, with the barrier to rotation arising from interactions between substituents on the aromatic rings ( Figure 2 a). The first compounds exhibiting atropisomerism to be resolved were 6,6′-dinitro-[1,1′-biphenyl]-2,2′-dicarboxylic acid ( Figure 2 b) and 4,4′,6,6′-tetranitro-[1,1′-biphenyl]-2,2′-dicarboxylic acid [ 15 ], although the possibility of such forms of enantiomerism has been predicted earlier by a number of authors [ 16 , 17 , 18 ]. It was left to Werner Kuhn to introduce the term atropisomerism ( atropisomerie ), derived from the Greek ατροπος (atropos) meaning “without turn”, to describe this phenomenon [ 19 ].…”

Through a Glass Darkly—Some Thoughts on Symmetry and Chemistry

“…The term was introduced by Richard Kuhn in 1933 and is derived from the Greek word ατρoπoς (without turn) [306]. The first biaryls to be resolved were 6,6'-dinitro-[1,1'-biphenyl]-2,2'-dicarboxylic acid (and 4,4',6,6'-tetranitro-[1,1'-biphenyl]-2,2'-dicarboxylic acid [307] although the possibility had been predicted earlier [308][309][310]. Clearly, there is no fundamental difference in axial chirality associated with allenes and biaryls, although only the latter could be described in terms of atropisomerism as this term is limited to restricted rotation about a single bond.…”

The Stereochemistry of Diphenyls and Analogous Compounds.

“…The former was shown definitely to be the 3,3'-dinitro derivative (XX) (26,23), and the second apparently had the nitro groups in the same positions. In 1912, Cain and his coworkers (29,30,31) adopted the Kaufler structure to explain the existence of these conventionally inexplicable isomers; he called the one a 3,3'-dinitro derivative (XXI), and the other a 3,5'-dinitro derivative (XXII); further support of such a viewpoint resulted from the experiments of Brady and McHugh (23). Later, Cain Still another pair of stereoisomers was discovered.…”