Methyl groups, lateral substituents

The effect of lateral methyl groups in the spacer on the phase behavior has been studied in several polybibenzoates [18,19] derived from poly(tetramethy]ene p,p bibenzoate), P4MB. The branched polymers display transition temperatures significantly lower than P4MB. Moreover, the substituents have a clear effect on the kind of mesophase formed. Thus, P4MB displays a smectic A mesophase, while the lateral methyl groups... 

Partial Rate Factors for Protodedeuteration in Perchloric Acid Solution. All lignin model compounds studied contained hydroxyl, methoxyl, and methyl groups as the only substituent groups. Table II summarizes what the authors believe are the most reliable partial rate factors for these substituents in perchloric acid solution. All partial rate factors are based on determinations in 57% perchloric acid solutions. The partial rate factors for ortho and para positions of methyl and methoxyl groups are based on later work by Suzuki (21). The partial rate factors for phenol were calculated from data on 2, 4, 6-trideuterophenol (6) using the value 9.1 X 10-5 hr.-1 for monodeuterobenzene by Suzuki (21) and assuming 1 3.2 ortho to para ratio. 

Figure 4 illustrates the "standard" model generated by CAMSEQ/M. This structure may be saved for later use, and/or be used as an input structure for a conformational study. The structure may later be used as a substructure for studying other congeners, by modifying its substituents. For example, amphetamine may easily be constructed by adding the alpha-methyl group to the ethylamine sidechain. The stereochemistry of the molecule is determined by the order of input of the substituents. 

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