摘要:

AbstractThe Boc‐aminoacyl‐OCH2‐Pam‐ derivative of Kel F‐g‐styrene resin has been synthesized by a chemically unambiguous route. Direct amidoalkylation of the unsubstituted resin followed by hydrazinolysis gave the aminomethyl‐resin. The loaded resin was obtained by reaction with a Boc‐aminoacyl‐OCH2‐phenylacetic acid and DCC. The stability of this resin derivative towards acidolysis in trifluoroacetic acid was determined. Only 0.01–0.02 mol% loss of chains will occur in a single deprotection cycle in solid phase peptide synthesis. The peptidyl‐ and aminoacyl‐OCH2‐Pam‐(Kel F‐g‐styrene) resins were cleaved with anhydrous HF‐anisole at 0°C in near‐quantitative yield. Simultaneous syntheses of the model peptide Leu‐Ala‐Gly‐Val on this resin and on Val‐OCH2‐Pam‐poly(styrene‐co‐1% divinylbenzene) resin gave the same low levels of byproducts. No (<0.1%) intersite aminolysis was observed on treatment of Leu‐Ala‐Gly‐Val‐OCH<2‐Pam‐(Kel F‐g‐st

ISSN:0021-2148    

DOI:10.1002/ijch.197800043

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractA 1 or 2% crosslinked divinylbenzene‐styrene copolymer, incorporating benzyl alcohol groups (1) was treated withp‐nitrophenyl chloroformate to give a polymer‐bound benzylp‐nitrophenyl carbonate (2). The reaction of (2) with an excess of the symmetrical diamines 1,4‐diaminobutane (3a), 1,6‐diaminohexane (3b), 1,8‐diaminooctane (3c), 1,10‐diaminodecane (3d) and 1,12‐diaminododecane (3e) gave the respective monoprotected polymer‐bound aminocarbamates (4a‐e). Benzoylation or tosylation of (4a‐e) gave the polymer‐bound N‐benzoyl or N‐tosyl carbamates (7a‐e) or (8a‐e) respectively. Cleavage of (7a‐e) with trifluoroacetic acid liberated the N‐benzoyl‐N'‐trifluoroacetyl‐1, ω‐diaminoalkanes (9a‐e) in 80% yield. Cleavage of (8a‐e) with HCl in benzene, followed by acetylation yielded N‐acetyl‐N'‐tosyl‐1, ω‐diaminoalkanes (11a‐e) in 80% yield. From both cleavage reactions about 20% of the symmetrical diamines were recovered as their N,N'‐ditrifluoroac

ISSN:0021-2148    

DOI:10.1002/ijch.197800044

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractCrosslinked resins containing styrylboronic acid units were used in the protection of 1,2 and 1,3‐diol groupings with several acyclic triols. With 1,2,3‐propanetriol, a five‐membered ring boronate was formed almost exclusively while with 1, 2, 4‐butanetriol a six‐membered ring boronate predominated. The fully recyclable polymer could be used in a fast and efficient synthesis of monobenzoyl derivatives of triols. Macroreticular and 1% crosslinked solvent‐swellable resins were tested and the latter were found to perform better on r

ISSN:0021-2148    

DOI:10.1002/ijch.197800045

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractRedox polymers are among the most well‐documented polymer reagents, and tailored redox polymers are obtainable. The synthesis and the redox properties of some new silica‐anchored quinones are described. A high redox reaction velocity was found with a modified pore‐controlled glass. Polymer reagents with N‐chlorobenzotriazole units were obtained from suitable benzotriazole derivatives or by polymer‐analogous reactions starting fromp‐aminostyrene polymers. With these products chlorinations as well as mild oxidation reactions were performed with good yields. Reusability and mechanical propertie

ISSN:0021-2148    

DOI:10.1002/ijch.197800046

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractSeveral S‐acetyl and S,S‐diacetyl derivatives of dihydrolipoic acid and amide were prepared as model compounds to examine acyl transfer reactions similar to those in living systems. A macromolecule bearing the lipoic acid (1,2‐dithiolane) structure was synthesized by polymer reaction of polyacrylamide. The acyl transfer from these S‐acetates to nucleophiles such as amine, alcohol and thiol as well as the catalytic behavior of silver ion in these reactions was

ISSN:0021-2148    

DOI:10.1002/ijch.197800047

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

Abstract(Polystyrylbipyridine)palladium(0) is an active catalyst for the selective hydrogenation of dienes to monoenes under mild conditions. Swelling solvents, such as tetrahydrofuran or benzene, are useable under 1 atm hydrogen at 25°C. The hydrogenation of linear isomers of hexadienes results in the formation of 1‐, 2‐ and 3‐hexene in each case. The hydrogenation occurs at the same rate for each of the hexadienes and<1% hexane is observed until after consumption of the first equivalent of hydrogen. Cyclohexadiene undergoes hydrogen transfer to form cyclohexene and benzene. The chemistry observed is distinct from that observed in Bailar's use of (℗‐Ph‐CH‐2P(Ph2)2PdCl2as a hydrogen

ISSN:0021-2148    

DOI:10.1002/ijch.197800048

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractPartially graphitized carbons were functionalized by carboxylic groups which were esterified with 4‐hydroxybenzaldehyde. A chiral diphosphine moiety, analogous to the DIOP framework, was then synthesized from the aldehyde function. The supported chiral diphosphine was transformed into a rhodium catalyst. Preliminary results of asymmetric hydrogenation or asymmetric hydrosilylation are describe

ISSN:0021-2148    

DOI:10.1002/ijch.197800049

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractThe synthetic possibilities of the generalized benzoin condensation are examined: benzoin condensation in its strict sense and closely related reactions, Michael type additions of aldehydes to activated double bonds, and oxidative benzoin condensation. In solid phase chemistry, comments are made on cyanide resins and details are given on the preparation of insoluble 5‐(2‐hydroxyethyl)‐4‐methyl‐3‐(polystyrylmethyl)thiazolium chloride and of 4‐methyl‐3‐(polystyrylmethyl)thiazolium chloride. Examples of the use of polymer thiazolium salts in the three types of reactions mentioned are presented and information on the stability of these s

ISSN:0021-2148    

DOI:10.1002/ijch.197800050

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractSelectivity has been investigated for the catalytic hydrogenation of alkenes using a polymeric catalyst derived from a polystyryldiphenylphosphine resin and tris(triphenylphosphine)chlororhodium (I). These data together with the selectivity observed for a closely related polymeric phosphine reagent capable of converting alcohols to alkyl chlorides provide compelling evidence that a polymer support can impose a modest degree of size‐selectivity to an attached reagent and catalys

ISSN:0021-2148    

DOI:10.1002/ijch.197800051

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractRecent studies of reaction rates in polymer systems are reviewed. These involve ionic reactions in polyelectrolyte solutions, kinetic effects due to the nature of the “effective solvent medium” in the polymer domain, neighboring group effects in polysaccharide oxidation, intramolecular polymer reactions involving non‐neighboring groups, the quenching of the fluorescence of groups attached to a polymer by species carried by another polymer chain and the photoisomerization of azobenzene residues in the backbone of polymer c

ISSN:0021-2148    

DOI:10.1002/ijch.197800052

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY