Biphenyl groups

This derivative is readily cleaved by acidic hydrolysis (dil. CF3COOH, CH2CI2, 10 min, quant.). It is cleaved 3000 times faster than the r-BOC derivative because of stabilization of the cation by the biphenyl group. BnSH... 

Polybibenzoates are a kind of thermotropic polyesters obtained by polycondensation of 4,4 -biphenyldicar-boxylic acid (p,p -bibenzoic acid) with a diol. These polyesters contain the biphenyl group, which is one of the simplest mesogens. They are synthesized by melt transesterification of the dimethyl or diethyl ester of p,p -bibenzoic acid and the corresponding diol, using a titanium compound as catalyst, according to the following scheme ... 

Several works have been published about the phase behavior of polybibenzoates, showing the ability of the biphenyl group to produce mesophase structures. Different spacers have been used, and the results show that the structure of the spacer influences very much the transition temperatures and the nature and stability of the mesophases, as well as the ability to generate three-dimensional crystals. 

Dihedral angle between the phenyl rings of the biphenyl group. 

Stacked together along the a-axis. The long molecular axes are tilted by 13° within the layers. By Raman spectral measurements Tashiro et al. found that the biphenyl group of the compound has a twisted structure in the liquid crystalline state as well as in the a-form. 

Tarzia et al. [69, 70] have recently reported the FAAH inhibitory activity of a series of alkylcarbamic acid aryl esters. The starting point for their studies was the known serine hydrolase inhibitor carbamyl (51) that had no activity at FAAH. Replacement of the small methyl group of carbamyl (51) with more lipophilic groups and, in particular, bulky lipophilic groups resulted in increased affinity at FAAH (Table 6.6). Exploration of replacements of the naphthyl moiety revealed that replacement with a biphenyl group resulted in improved affinity and in particular, the 3-biphenylyl group proved effective... 

Table III. Reaction Conditions and Results of Synthesis of PRO Containing Biphenyl Groups ...

R)- and (S)-(6,6 -Dimethylbiphenyl-2,2 -diyl)bis(diphenylphosphine), BIPHEMP (1). This is the first example of an optically active bis(triarylphosphine) containing the axially disymmetric biphenyl group. The 6,6 -dimethyl groups are used to... 

GfSOj) for Hq/Bp (50) PSF is intermediate between G(S02> for the homopolymers. Thus, there is no additional protective effect analogous to the non-linear response of G(H.) as the mole fraction of benzene in cyclohexane is increased (3.47. This indicates that the spatial range of enhanced radiation protection afforded by the biphenyl group is limited. 

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