Poly catalytic hydrogenation

Catalytic hydrogenation giving optically active compounds was accomplished over palladium on poly() -S-aspartate) and on poly(y-S-glutamate) [75] and over rhodium on phosphine-containing substrates [16,17,18,19,20. Optical yields up to 93% were reported [76],... 

Here hydrocarbon conversion reactions occur wholly or at least partly on the carbonaceous overlayer on the metal and oxide surfaces, as reported by others (13,15-20). Poly-condensed EDA complexes may behave as giant alkenes in which by reversible catalytic hydrogenation/dehydrogenation occurs. This mechanism is similar to the intermolecular hydrogen transfer mechanism proposed (IS) for hydrogenation of unsaturated hydrocarbons. 

Three common procedures are available for the transformation of aldehydes and ketones to hydrocarbons (1) reduction by zinc and hydrochloric acid (Clemmensen), (2) reduction by hydrazine in the presence of a base (Wolff-Kishner), and (3) catalytic hydrogenation. In view of the complicated mixtures obtained by the polyalkylation of benzene by the Friedel-Crafts reaction (method 1), reduction of alkyl aryl ketones is the most reliable method for the preparation of di- and poly-alkylbenzenes. 

The phthalimidomethyl ester protectionO l has been used for the synthesis of poly-L-glutamic acid.f l This protecting group is cleaved by piperidine or sodium hydroxide, but it is also sensitive to acids and catalytic hydrogenation. The co-ester is prepared by reacting Z-Glu-OBzl with A-chloromethylphthalimide in the presence of DCHA. Owing to its characteristic absorption at 299 nm, the reaction can be monitored spectrometricaUy. 

Enantioselective heterogeneous catalytic hydrogenation using a chiral catalyst was pioneered by Aka-bori and Izumi, who prepared a palladium catalyst supported on silk fibroin. The oxime acetates of diethyl a-ketoglutarate or of ethyl phenylpyruvate were hydrogenated to form glutamic acid (7-15% ee) and phenylalanine (30% Similarly, a palladium-poly-L-leucine catalyst was used for the asym-... 

CCT of benzyl methacrylate leads to a mixture of poly(benzyl methacrylate) macromonomers from which the dimer macromonomer could be isolated.516 When the benzyl dimer is used as a RAFT chain-transfer agent, PMMA with a- and co-terminal benzyl methacrylate units is obtained. Catalytic hydrogenation of the a,co-benzyl terminal methyl methacrylate polymer results in the evolution of toluene and formation of a,co-dicarboxyl functional telechelic PMMA. 

To construct the B-ring, the unprotected hydroxymethyl group of the poly-hydroxypyrrolidine was oxidized into an aldehyde and a Wittig reaction was used to install the required ketone functitm at C-2 providing intermediate 87, ready for the subsequent nucleophilic cycUzation of the free amine (Scheme 18). Several subsequent catalytic hydrogenation steps were performed to provide, first the ketone 88, which was then submitted to the addition of HCl under an hydrogen atmosphere to achieve the N- and 0-deprotection leading to the amine 89. 

Marshall, A.R. and U.H.F. Bunz. 2001. Alkyne-bridged polymers as platform for novel macromol-ecular materials Catalytic hydrogenation of poly[(p-dialkylphenylene)ethynylene]s. Macromolecules 34 4688. 

The catalyzed polyaddition of the monomer 2-deoxy-l,4 3,6-dianhydro-2-isocyanato-L-iditol gave the corresponding polyurethane [103]. However, the intermediate aminochloroformyl derivative undawent spontaneous poly condensation by catalytic hydrogenation. 

Q-P(BMAE)19 was obtained according to the followii route, based on catalytic hydrogenation of poly(N-sec-butyl-N-methyl acrylamide) and partial methylation of the resulting polytertiary amine using ICH3 in benzene. 

Ruzicka, L., H. Leuenberger, and H. Schellenberg Polyterpenes and Poly terpenoids. 118. Catalytic Hydrogenation of the a,p-Unsaturated Keto Group in Glycyrrhetic Acid and Keto-a-amyrin. Helv. Chim. Acta, 20, 1271... 

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