Biphenyl 2-carboxy-4 -methoxy

Dimethylamino-methyl)-2-hydroxymethyl-aus 2 -Carboxy-2-(dimethylaminocarbonyl)-biphenyl und Lithiumalanat 165 2,2 -Dinitro- 474, 476, 695 6,6 -Dinitro-2,2 -bis-[chlorcarbonyl]- 188 2,2 -Dinitro-4,4 -bis-[diathylamino]- 695 4,4 -Dinitro-2,2 -bis-rhydroxymethyl]- 213 6,6 -Dinitro-2,2 -bis-[hydroxymethyl]- 188 2,2 -Dinitro-4,4 -diamino- 695 6,6 -Dinitro-2,2 -diformyl- 694 4,4 -Dinitro-2,2 -dimethoxycarbonyl- 213 2,2 -Dinitro-4,4 -dimethyl- 695 6,6 -Dinitro-2 -formyl-2-carboxy- 694 2,2 -Dinitroso- 476 -4-hydroxamsaure-chlorid 537 4-(a-Hydroxy-benzyl)- 542 Methoxy- 678 2-Methyl- 556 Nitro- 672, 678 4-Nitro- 687... 

Azulen 3-Ethoxycarbonyl-2-hydroxy-1 -nitroso- V/2c, 298 Biphenyl 4-Hydroxy-4 -methoxy-3-nitro- E16d, 301 (Nitrierung) Naphthalin 3-Carboxy-2-(carboxymethyi-amino)- -Dikaiium-Salz E6b/1, 653 (NH2 - NH-COOH)... 

Biphenyls containing four large groups in the ortho positions cannot freely rotate about the central bond because of steric hindrance. For example, the activation energy (rotational barrier) for the enantiomerization process was determined, AG = 21.8 0.1 kcal mol , for the chiral 2-carboxy-2 -methoxy-6-nitrobiphenyl. In such compounds, the two rings are in perpendicular planes. If either ring is symmetrically substituted, the molecule has a plane of symmetry. For example, consider the biaryls ... 

The optical activity of the tri- and tetra-orr/zo substituted biaryls (atropisomers) is a consequence of the chiral axis, present in this structure. The configuration R- or S-) of these compounds is matched according to the Cahn-Ingold-Prelog (CIP) system and an additional sequence rule Near groups precede far groups. An example with 2-chloro-6-methoxy-2 -nitro-6 -carboxy-l,T-biphenyl (9) is illustrative. Figure 2 ... 

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