The Synthetic Concept

The structure of remikiren suggested the assembly of three chiral building blocks, namely sulfone (S)-3, (S)-histidine ester 4 and aminediol 5 (see the structures in Fig. 4). 

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Hydroxyproline-derived polyesters represent a specific embodiment of the synthetic concepts described in Fig. la. The successful synthesis of a hydroxyproline-derived polyester was first reported by Kohn and Langer in 1987 (12). Thereafter, several of these new polyesters were investigated in detail by Yu and Lange (21-23). 

An application of the synthetic concept to carbon analogs is not possible. LiSPh-elimination and/or LiSPh-elimination after previous H,Li exchange occurred for alkyllithium-intermediates formed by reductive cleavage of C-S bonds. Reaction of this type have been observed for similar compounds [7]. The silicon atom obviously plays a central role in the reactivity of the presented structure types. 

The synthetic concept is simple. Benzyl cyanide is alkylated twice with /5 -bis-(chloroethyl)methylamine, and the nitrile function transformed into the ethyl ester in a Pinner reaction with ethanol... 

Interestingly, there are new studies by DSM/Hoffmann-La Roche on the laboratory-scale synthesis of various carotenoids, like astaxanthin and also canthaxan-thin, entirely without a Wittig reaction. [70] They follow the synthetic concept... 

Following the synthetic concept described for carboxylic acid functionalized resins [2], dipyridyl amide functionalized resins have been prepared[3]. Synthesis of the starting monomer was achieved by reaction of cyclopentadiene with acrylic acid chloride at 0°C. A... 

The synthetic concepts by which these compounds are synthesized are as nvunerous as the different materials themselves. They range from classical hydrothermal reactions, via molten flux methods to pure precipitation reactions. As diverse as the conditions employed to synthesize such compoimds are... 

Contributing to ongoing efforts toward the miniaturization of analytical devices and to develop systems applicable to the coupling to highly sensitive quantification methods such as mass spectroscopy, Buchmeiser et al. reported on an extension of the concept of ROMP-derived monolithic supports to the synthesis of capillary columns. Transferring the synthetic concepts, methods, and procedures elaborated for semipreparative scale separations to 0.2 mm i.d. capillaries, high resolution was achieved in the separation of the oligodeoxynucleotides (dT)i2-i8 (2.27 [Pg.619]

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