Dimerizations synthesis

Cost. It is necessary to produce the feedstock from which the monomer is generated, viz, the dimer, at a cost which can be supported by the commercial appHcation, and yet allow it to be economically competitive with all other alternative ways to achieve the same end result. This factor often, but not always, seriously limits the amount of effort that can be put iato dimer synthesis and purification. 

Katsuki-S harpless epoxidation, 48, 1 Ketene cycloadditions, 45, 2 Ketenes and ketene dimers, synthesis of, 3, 3 45, 2... 

Jung, J.H., Takehisa, C., Sakata, Y., and Kaneda, T. (1996) p-(4-Nitrophenylazo)phenol Dye-bridged Permethylated a-Cyclodextrin Dimer Synthesis and Self-aggregation in Dilute Aqueous Solution, Chem. Lett. 147-148. 

N4-diamide alkyl-substituted, 141 dimer, synthesis of, 142 dimethyl-substituted, 141 p-cyanophenyl-substituted, 141 synthesis of 141... 

Scheme 3. Smith and Heathcock s unsymmettical dimer synthesis.

Jung JH, Takehisa C, Sakata Y, Kaneda T. 1996. p (4 Nitrophenylazojphenol dye bridged permethylated a cyclodextrin dimer synthesis and self aggregation in dilute aqueous solution. Chem Lett (2) 147 148. 

In the next step, pleiadene dimerizes. Synthesis of either ( )-3,5-dimethoxystil-benes or 3,5-dimethoxydibenzyls was carried out by selective removal of the 4-methoxy group of 3,4,5-trimethoxystilbenes I (Ri = MeO Ar = Ph, 2-MeOCfiH4, 3-MeOC6H4, 4-MeOC6H4, 3,4,5-(MeO)3C6H2) [75]. The reaction was performed under electron transfer conditions with Na metal in THE. It was shown that 4, 4"-diethylstilbestrol quinone reacted with nucleosides, nucleotides, and amines... 

In attempts to reconstitute nucleosomes on SV40 circular DNA, Cap-lan et al. (37) observed that if the histones were ADP-rihosylated prior to reconstitution assembly of nucleosomes was inhibited by as much as 80%. If nucleosomes were first allowed to assemble, then modified by ADP-ribosylation, no eflPect on stability was observed. These data led the authors to speculate that ADP-ribosylation of histones prior to nucleosome assembly might be of physiological importance. Perella and Lea (168, 169) have shown that in rat liver nuclei, polyamines cause an increase in histone Hi ADP-ribosylation and histone HI dimer synthesis, which is accompanied by a decrease in core histone ADP-ribosylation. Data such as these have led to speculation that Hi dimer formation may function in the condensation or stabilization of chromatin fibers (35, 119). The data of Lorimer et al. (124) indicate that dimer synthesis is inversely related to the nuclear activity of the poly(ADP-ribose) glycohydrolase. Thus, these authors (124) inferred that the Hl-Hl-polymer complex formation is of a transient nature. As pointed out by Purnell et al. (171), if this crosslink were to function in the stabilization of chromatin, the modified histone Hi would have... 

The solid-state chemistry of coumarin has also received considerable attention, mainly due to the biological importance of coumarin derivatives, and has been summarized in several reports. " In a comprehensive study of nearly 30 coumarin derivatives in the solid state, Venkatesan, Ramamurthy, and co-workers discuss the criteria for topochemical reactivity in the solid set forth 20 years earlier by Schmidt. Their results, though not invalidating previous guidelines for solid-state reactivity, indicate that caution, rather than rigor, is recommended in their application. The irradiation of coumarin within chiral inclusion complexes has also been used as a means to achieve enantioselective dimer synthesis. " ... 

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