Synthesized model compounds

The existence of the above complexes has been conclusively proved by use of specially synthesized model compounds (Table 3) and by IR-spectroscopic studies over a wide range of substance concentrations (diluent CC14). 

In the case of synthetic studies on mitomycins (e.g. mitomycin A), both techniques were applied to synthesize model compounds. A retro aldol reaction, followed by a trivial transannular reaction, was performed in the same pot and under the same conditions (sodium hydride) [79] [80], Scheme VIII/25. Thus, compound VIII/132 gave the ring closed intermediate, VIII/133, which by a retro aldol reaction, yielded the eight-membered intermediate, VIII/134. A transannular reaction in VIII/134 gave the acid labile VIII/135, which led finally to the indole derivative, VIII/136. 

In summary, quantum mechanical calculations can provide importance guidance in identifying chromophore structures, leading to improved molecular hyperpolarizability however, such guidance is not foolproof and should be validated by preparation of more easily synthesized model compounds before launching into the synthesis of complicated chromophore molecules with all of the requirements necessary for utilization in device prototyping. 

In the presence of alcohols, the reactive species is a carbenium ion (4), formed from the hemiacetal (5) (Eq. 7). Efforts to synthesize model compounds continue the work started by Bender and coworkers. A series of new dimeric and trimeric compounds, derived from o-cresol, have been synthesized and their structures determined by IR, NMR, and elemental analysis. Additional homologues of p-cresol have been prepared by Kammerer and Niemann, to study the melting behavior of a wide range of methylene-bridged phenol oligomers. Prepolymer formation, namely novolac production, has been studied in batch and continuous flow reac-... 

NIR spectroscopy was used to quantify the cure reaction of MDEA-epoxy resins (E/A = 1.4) carried out at 72 and 160°C. Anew assignment for the secondary amine at 6580 cm was proposed, supported by a synthesized model compound. Two different spectral treatments were proposed. One was based on normalization at 4610 to 4620 cm while the another was based on the subtraction of the normalized spectrum of a cured sample. Quantitative results were obtained from absorbance measurements in the combination region, while spectral decompositions and area measurements were necessary in the overtone region. The resulting complementary information allowed calculation of conversion rates of epoxide and amine I, and concentrations of amine II, amine III, hydoxyl groups, and ether links [96]. 

Synthesize model compounds, which contain structures similar to those predicted in the photodegraded polymer sample and establish resonance-structure relationships. 

Lim ASC, Solomon DH, Zhang X. Chemistry of novolac resins. X. Polymerization studies of HMTA and strategically synthesized model compounds. J Polym Sci A 1999 37 1347. 

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