摘要:

AbstractThe random copolypeptides of β‐benzylL‐aspartate (β‐BzL‐Asp) and γ‐methylL‐glutamate (γ‐MeL‐Glu) were synthesized and implanted subcutaneously in rats. It was found that the resulting copolypeptides are degraded and also have good biocompatibility in vivo. On the basis of these results, poly(β‐BzL‐Asp‐co‐γ‐MeL‐Glu) was tried to be used as a material for a drug delivery system. Copolypeptide‐testosterone composites were prepared at a pressure of 200 kg/cm2in the presence of a slight amount of dichloroethane. The in vivo release rate of testosterone from copolypeptide‐drug composites was about 5,5 times higher than that in vitro. The in vivo release rate remained relatively constant over a period of 90 days at 0,22 mg/day. The serum testosterone concentration in castrated rats was 0,40 ng/ml and the value went up to 6,8 ng/ml after the biodegradable copolypeptide‐testosterone composite was implanted and was

ISSN:0025-116X    

DOI:10.1002/macp.1983.021840901

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractAsymmetric inclusion polymerization of the prochiral monomers (E)‐ and (Z)‐2‐methyl‐1,3‐pentadiene(3aand3b), in apocholic acid(2)canals was performed under various conditions to find out the factors controlling the asymmetric induction during the polymerization. Ozonolysis of the resulting polymers and subsequent transformation of the resulting 2‐methyl‐4‐oxovaleric acid(4)into its 2,4‐dinitrophenylhydrazone revealed the predominant formation of the (R)‐absolute configuration. The optical yield was high in the initial stage of the polymerization and decreased gradually as the polymerization proceeds. To obtain a high optical yield the polymerization was performed at low temperature applying a 1:1 mole ratio monomer/apocholic acid, and an irradiation dose<1 Mrad. The optical yield amounted to 36% at maximum, which is the highest value obtained so far in the asymmetric polymerization of 1,3‐pentadiene derivatives using canal complexes o

ISSN:0025-116X    

DOI:10.1002/macp.1983.021840902

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractAddition of a higher lactam (ε‐caprolactam or 8‐octanelactam) to the nonactivated polymerization of 2‐pyrrolidone, initiated with potassiumtert‐butoxide or the isolated potassium salt of 2‐pyrrolidone, does not lead to the formation of a copolyamide. Only a marked decrease of polymerization rate is observed and the maximum rate of 2‐pyrrolidone homopolymerization shifts to a lower temperature. The possible causes of this interesting phenomenon a

ISSN:0025-116X    

DOI:10.1002/macp.1983.021840903

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe kinetics of the electrophilic bromination of 17 oligonuclear phenolic compounds with molecular bromine in acetic acid were studied at 22°C. Some of these compounds, consisting of up to 6 phenolic units, which are linked in ortho‐position by methylene bridges, and having only one (or two) reactive ortho‐position(s) at the end of the molecule, were synthesized for the first time. It could be shown, even for hexanuclear compounds, that the variation of substituents at one end of the molecule leads to a change in the reactivity at the other end, that means over a distance of 22 nonconjugated covalent links. So far, this can be explained only by a chain of intramolecular hydrogen bonds between the phenolic hydroxyl groups of adjacent phenolic units. If this chain is interrupted by one methoxy group, a substituent effect cannot be transferred in the same

ISSN:0025-116X    

DOI:10.1002/macp.1983.021840904

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractTransformations of oxy(halomethyl)methylsilanediyle units or oxy(acetoxymethyl)methyl‐silanediyle units into oxy(hydroxymethyl)methylsilanediyle units in homogeneous and heterogeneous polysiloxanes were investigated. Si‐C‐cleavage and SiOSi‐rearrangement were studied on disiloxanes and oligosiloxanes used as models of the corresponding polymers. Methanolysis of poly[(acetoxymethyl)methylsiloxane]s and their copolymers catalysed byp‐toluenesulfonic acid was applied to obtain poly[(hydroxymethyl)methylsiloxane]s and the

ISSN:0025-116X    

DOI:10.1002/macp.1983.021840905

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractLinear and branched siloxanes were prepared by partial hydrolysis of silicon tetrachloride and by esterification of the products of hydrolysation with methyl and ethyl nitrite.29Si NMR spectra made it possible to distinguish between the isomers of each oligomer up to the heptamer. Linear relationships between the29Si chemical shifts of the ethyl and the methyl esters on one hand and between the ethyl esters and the poly(silicic acid)s on the other hand were observed. However, due to the different effect of neighboring building units, there are only poor relationships between the29Si data of the esters and the chloro derivatives.

ISSN:0025-116X    

DOI:10.1002/macp.1983.021840906

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractA newD,L‐polysaccharide, 4‐deoxy‐(1→6)‐α‐D,L‐xylo‐hexopyranan(3), containing two hydroxyl groups in its repeating unit was synthesized, starting from 3,4‐dihydro‐2H‐pyran‐2‐carbaldehyde(4)(Acrolein dimer). The monomer, a bicyclic acetal, 3(a),4(a)‐bis(benzyloxy)‐6,8‐dioxabicyclo[3.2.1]octane(1)was prepared from the starting material via six step reactions. The cationic ring‐opening polymerization of1was effectively achieved by using antimony pentachloride or trifluoromethanesulfonic acid as initiators to afford the polyacetal2with number average molecular weights of up to 1,2 · 105. Debenzylation of2with sodium metal in liquid ammonia gave rise to a white powdery polymer identified as3by13C‐NMR spectroscopy. The synthetic polysaccharide3melting in the range of 90 to 103°C was found to be soluble in dimethyl sulfoxide and water, and insoluble in other common organic solvents. Water sorption of3was measured at different relative humidities between 32 and 97% and compared with those of natural dextran and a synthetic polysa

ISSN:0025-116X    

DOI:10.1002/macp.1983.021840907

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractCellulase was immobilized on a porous polymer matrix which was formed by radiation polymerization of bifunctional monomers such as poly(ethylene glycol) diacrylates(1), and the nature of the porous polymer matrix and its effect on the enzymatic activity was studied. The porous structure of the polymer matrix was found to change markedly with the monomer concentration and irradiation temperature. The formation of the porous structure shows a discontinuous change in the temperature region of −10 to −40°C, due to the change in polymerization phase and mechanism. The enzymatic activity is strongly related to the pore size, the degree of hydration of the polymer matrix, and the particle size of the composite. The degree of hydration of the polymer matrix varies with the number of oxyethylene units in the monom

ISSN:0025-116X    

DOI:10.1002/macp.1983.021840908

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

Abstract1,1′‐Diisopropenylferrocene(1a)was homopolymerized using trifluoroacetic acid or boron trifluoride etherate as initiators, with excellent yields (>90%) of polymer (8100

ISSN:0025-116X    

DOI:10.1002/macp.1983.021840909

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractPolyoxiranes with amino, carboxyl, or halogeno end groups were prepared by polymerization of oxirane with either anionic initiators substituted with functional or protected functional groups, or by reaction of functional deactivating reagents with anionically prepared polyoxiranes. For the protection of primary amino groups they were transformed into the corresponding cyclic imido derivatives. The deactivation of polyoxirane with potassium oxido end groups by bis(halogenomethyl)benzenes was studied with the three isomers.

ISSN:0025-116X    

DOI:10.1002/macp.1983.021840910

出版商:Hüthig&Wepf Verlag    

年代:1983

数据来源: WILEY