N- -benzamide

Water is used to remove excess sulfuric acid, and ethyl acetate to remove triphenylmethanol, benzophenone and the N-benzamide derivative of proline. 

As yet, the structure of only one pyrrolidine from a dendrobatid frog has been firmly established (96). This is pyrrolidine 197B, whose structure was established by comparison with synthetic /ra/i5-2-/i-butyl-5-n-pentylpyrrolidine. The structure of 197B is shown in Fig. 20, along with tentative structures for two other dendrobatid pyrrolidines. The absolute stereochemistry of 197B was established as (25,55) by comparison on chiral gas chromatographic columns of the N-benzamide of 197B with N-benzamides of synthetic d- and /-enantiomers (156,157). 

As a result of this and Eq. 2.4, Hammett constants directly influence the complex formation eqnilibria, although to varying extents depending on whether this is first-order or second-order, the latter due to aromatic substitution next to different donor sites (P (phosphines), N (benzamides, pyridines or pyrazininm ions), S (thiophenolates) or O (phenolates, benzoates, combinations like salicylate derivates) or combinations thereof (see case c. above) (salen derivatives or those of hippnric acid, both linked to metal by N -t- O)). 

The work by Ciferri and coworkers [128-130] focused on the supramolecular organization of aromatic rod-coil copolyamides in diluted (isotropic) and moderately concentrated (lyotropic) phases. Their diblock copolymers were based on a rigid block of poly(p-benzamide) (PBA) having a DP about 100, and different comparable lengths of flexible blocks, such as poly(m-phenylene isophthalamide) (MPD-I), poly(/n-benzamide) (MBA), or poly(ethylene glycol) (PEG). The use of end-capped prepolymers and selective extraction techniques assured a strict two-block sequence, the absence of free homopolymers not strongly bound to the copolymers, and a fractionation in terms of the rigid/flexible compositional distribution ratio. 

Fig. 1 Tg of hyperbranched polyamides (plane) and linear iV-alkyl poly(/n-benzamide)s as a function of M-...

Scheme 22 Synthesis of diblock copolymer of JV-octyl poly(/n-benzamide) and aromatic...

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