ISSN:0165-0513    

DOI:10.1002/recl.19821010701

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe synthesis of a total of twelve DNA fragments on the solid supports cellulose or polystyrene via a phosphotriester approach is described. Dimer and trimer blocks, protected at the 5′‐end with the levulinoyl group, were used for chain extension in the presence of the activating agent (2,4,6‐triisopropylbenzenesulfonyl)‐3‐nitro‐1,2,4‐triazole or (mesitylenesulfonyl)‐3‐nitro‐1,2,4‐triazole. The yields of the coupling procedures are normally high and the final unprotected DNA fragments released from the solid support could easily be isolated by Sephadex G50

ISSN:0165-0513    

DOI:10.1002/recl.19821010702

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe synthesis of the tridecaribonucleotide AAGAAGAAGAAGA on a polystyrene solid support via a phosphotriester approach is described. The assemblage of the oligomer was performed by four repeated coupling reactions of the partially protected trimer AAGp(3′) with an immobilized dimer in the presence of the activating agent (2,4,6‐triisopropylbenzenesulfonyl)‐3‐nitro‐1,2,4‐triazole. Purification of the RNA fragment was easily achieved by Sephadex G50 column chr

ISSN:0165-0513    

DOI:10.1002/recl.19821010703

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe solid‐phase synthesis of [Ile13, Met20]‐S‐peptide‐(Gly‐Gly) on a Merrifield resin, using tert‐butoxycarbonyl‐ and benzyl‐type protecting groups, is reported. Deprotection was achieved by reaction with liquid hydrogen fluoride and purification by ion‐exchange chromatography and HPLC.The above peptide was converted into [Ile13, Hse20]‐S‐peptide lactone by reaction with cyanogen bromide. Reaction of the synthetic 20‐peptide lactone with “native” bovine S protein at pH 7.5 resulted in the formation of [Ile13, Hse20]‐RNase A in about 10% yield. The semisynthetic enzyme was purified by ion‐exchange chromatography and the kinetic parameters were deter

ISSN:0165-0513    

DOI:10.1002/recl.19821010704

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe complete assignment of the 18 ribose proton NMR signals of the trinucleoside diphosphate m62A(1)‐U(2)‐m62A(3) is given. The analysis was carried out by means of spin‐echo‐correlated spectroscopy and two‐dimensionalJ‐resolved spectroscopy at 500 MHz. Analysis of the chemical shifts and coupling constants demonstrates that the trimer does not form a classical right‐handed helix. Instead, the interior U(2) fragment appears to be “bulged‐out”, concomitant with a next‐nearest‐neighbour interaction between the terminal purine bases. An analogy with the behaviour of the first three residues in the tetramer m62A(1)‐U(2)‐m62A(3)‐U(4) is noted. An analysis of the coupling constants in terms of the N/S equilibrium and population distribution around the torsional degrees of freedom along the sugar‐

ISSN:0165-0513    

DOI:10.1002/recl.19821010705

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe biliverdinium salt 1 has been prepared in high yield and its behaviour towards nucleophiles studied. The reactions have been found to occur selectively on the central carbon atom 10 and to lead to bilirubin systems. In addition, the photoisomerisation of the bilirubin model compound 5, prepared from 1, has been investigated.

ISSN:0165-0513    

DOI:10.1002/recl.19821010706

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe pressure dependence of the (2 + 2) cycloaddition of cyclopropanone diethyl acetal to tetracyanoethylene in methylene chloride and acetonitrile has been studied. The reaction is about ten times faster in the less polar methylene chloride in the pressure range 1‐2000 atm. The volume of activation is found to be ‐20.9 cm3/mole (CH2Cl2) and ‐24.5 cm3/mole (CH3CN). The estimated volume of the transition state is equal in both solvents and is of the same order of magnitude as the partial molar volume of the cycloadduct 1,1‐diethoxy‐2,2,3,3‐tetracyanocyclopentane. These findings are in agreement with a concerted cycloaddition mechanism via a weak complex of th

ISSN:0165-0513    

DOI:10.1002/recl.19821010707

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractA general method of preparation is described for glycino ethyl ester derivatives of phosphazene‐like ring systems, which may serve as precursors for anti‐cancer dr

ISSN:0165-0513    

DOI:10.1002/recl.19821010708

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe triplet photosensitization of the β, γ, β1, γ1‐dienone 2 leads to the formation of the DPM isomer 6 and the two ODPM isomers 7 and 8 in a ratio of 35:17:10. This is the first reported example of a substrate which exhibits intramolecular competition as demonstrated by the occurrence of both the DPM and ODPM rearrang

ISSN:0165-0513    

DOI:10.1002/recl.19821010709

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractCyclooctatetraene is a common product of photolysis of the title compound la. Depending on reaction conditions it is accompanied by benzene (solvent: cyclohexane, γ = 253.7 nm), benzene plus semibullvalene (acetone, 300 nm), and an oxetane (cyclohexane, 350 nm, presence of an equimolar amount of benzophenone)

ISSN:0165-0513    

DOI:10.1002/recl.19821010710

出版商:WILEY‐VCH Verlag    

年代:1982

数据来源: WILEY