摘要:

Synthesis of B1 Substituted Peptidyl InsulinsThe peptide derivatives Boc‐Leu‐Tyr(Bzl)‐Gln‐Leu‐OHNomenklatur und Abkürzungen nach den Regeln der IUPAC‐IUP‐Commission on Biochemical Nomenclature: Hoppe‐Seyler's Z. Physiol. Chem.348(1967) 256 und J. Biol. Chem.247(1972) 977.of the sequence section 13–16 of the insulin A chain and Boc‐Leu‐Tyr(Bzl)‐Leu‐Val‐Cys(SEt)‐Gly‐OH corresponding to the partial sequence 15–20 of the B chain are condensated with A1, B29‐Boc2‐insulin via their pentachlorphenylesters. After removal of the protecting groups by HBr/TFA in the presence of anisole and ethylmercaptan the corresponding insulins elongated in position B1

ISSN:0021-8383    

DOI:10.1002/prac.19873290102

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

About the Formation of trans‐Epoxides in the Liquid Phase Oxidation of cis/trans‐n‐Alkenes Catalyzed by TechnetiumThe liquid‐phase oxidation of n‐oct‐1‐ene, cis‐oct‐4‐ene and cis/trans mixtures of oct‐4‐ene with molecular oxygen in the presence of the technetium complexes1to10was studied. Low epoxide yields (≦10%) are characteristic features of the reactions. Pure cis‐oct‐4‐ene and mixtures of cis/trans‐oct‐4‐ene yields in cis/trans‐epoxide ratios lower than 0.05. Isomerization reactions and nucleophilic epoxide ring opening reactions are not responsible for the low epoxide yield and the favoured formation of trans‐epoxide. Epoxide decomposition by a Tc‐catalyzed radical reaction

ISSN:0021-8383    

DOI:10.1002/prac.19873290103

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractAn amidoalkylation of PCl3or its organic derivatives in acetic acid solution takes place because equilibrium between AcOH and exist, leading to hydroxychlorophosphines. Those last compounds undergo an amidoalkylation like other nucleophiles. Based on these data, it was shown that an amidoalkylation reaction is usual for all phosphorus compounds with the R2P(O)H system and provides derivatives with the functions. The scope and limitation of these reactions are discussed.

ISSN:0021-8383    

DOI:10.1002/prac.19873290104

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

Structure‐Dependent Properties of Detergents as Studied at 2‐Alkylsulphates, Phosphine‐oxides, and ω‐H‐Perfluoroalkyl CompoundsCMC values from δ/lg c‐curves were determined for the homologous series of 2‐alkyl‐branched alkylsulphates, dimethyl‐ an diethyl‐phosphine‐oxides and ω‐H‐perfluoroalkyl‐sulfosuccinates. On this basis effective chainlengths were calculated and correlated with other properties as maximum of surface tension depre

ISSN:0021-8383    

DOI:10.1002/prac.19873290105

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractStarting from (+)‐5β‐hydroxycyclopenten‐2‐yl‐1β‐acetic acid γ‐lactone (1), (+)‐1β‐methoxycarbonylmethyl‐2β, 3β‐(p‐nitrobenzylidene)‐dioxycyclopentan‐5‐one (7) was prepared within 4 steps. Subsequent cleavage of the latter gives (−)‐3β‐hydroxy‐1‐methoxy‐carbonylmethylcyclopent‐1‐en‐5‐one (8a). Hydroxylation of the lactone (1) was found to give (+)‐2β,3β,5β‐trihydroxycyclopentyl‐1β‐acetic acid γ‐lactone (2a) with cis‐oriented hydroxy groups in respect to the lactone ring. No form

ISSN:0021-8383    

DOI:10.1002/prac.19873290106

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

On 1.2‐Shift Reactions and CH‐Insertions of Acyclic Alkylidene CarbenesTwo series of acyclic terminal vinyl bromides (1…4and5…7) were tested in the reaction with potassium tert‐butoxide as precursors of alkylidene carbenes. As expected1up to4only give 1‐alkynes whereas the 2‐methylated vinyl bromides5,6and7yield 1‐methylated cyclopentenes predominantly besides 2‐alkynes. The formation of cyclopentenes indicates a reaction route via alkylidene carbenes and 1,5‐CH‐insertion reactions, that of 2‐alkynes is convincing evidence for 1,2‐alkyl shift reactions in 2‐methyl substituted alkylidene carbenes. The selectivity of 1,5‐CH‐insertion depends on the degree of alkyl substitution of the C‐5‐atom. At 240

ISSN:0021-8383    

DOI:10.1002/prac.19873290107

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

Intramolecular 1,3‐Dipolar Cycloadditions of Aryl Azides with Alkynyl SubstituentsReaction of substituted 4‐chlorobut‐2‐ynes1with 2‐acetaminophenol and 2‐aminothiophenol, respectively, leads to the corresponding ethers and thioethers3that can be converted into the alkynyl substituted aryl azides4by diazotation and reaction with sodium azide. Intramolecular 1,3‐dipolar cycloaddition yields 4H‐[1,2,3]triazolo [5,1‐c][1,4] benzoxazines and benzothiazines5. In the same way 1,4‐bis(2‐acetaminophenoxy)but‐2‐yne6reacts to a 3‐(2‐azidophenoxy‐methyl)‐triazolobenzoxazine9. Its thermal dec

ISSN:0021-8383    

DOI:10.1002/prac.19873290108

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractSchmidt reaction of the pyrazolo‐β‐(p‐anisyl)‐propionic acid3gave the pyrazolo‐anisylethylamine4. The related alkaloids5and6were obtained via double Mannich reaction of4with the bis‐Mannich base of cyclopentanone and transamination with gramine respectively. The pyrazolo‐phenylalanine9was obtained from the EAA adduct7, through its Schmidt reaction to give8followed by hydrolysis, whereas the pyrazolo‐amino acid12resulted from the hydrolysis of the corres

ISSN:0021-8383    

DOI:10.1002/prac.19873290109

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractThe reaction of a series of bis‐[1,4‐dihydropyridinyl‐(4)] derivatives P2with some benzyl halides, trans‐1,2‐dibromoethane and several heteroaromatic cations Q⊕was investigated in acetonitrile/toluene with electrochemical and kinetic methods. For substrates with a reduction potential between −0.9 and −1.5 V the reaction occurs via the ratedetermining dissociation of P2into free radicals P.as the real reducing agents, which transform the benzyl halides into the corresponding 1,2‐diarylethanes and Q⊕into the corresponding dimeric product Q2. For the reduction of trans‐1,2‐dibromocyclohexane to cyclohexene a simultaneous transfer of two electrons to the substrate combined with the dissociation of P2into two pyridinium ions P⊕is proposed. In the case of a reduction potential more positive than −0.9 V (e.g. nitro substituted benzyl halides) P2itself can act as the reducing agent with an increased reaction rate. With pyrylium ions Q⊕a product P‐Q was detected by voltammetry and mass spectroscopy. In this case an electrophilic attack onto P2instead of the electron transfer

ISSN:0021-8383    

DOI:10.1002/prac.19873290110

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

Attempts to Synthesize Sterically Hindered Thiazyl Arenes and Their Relationship to Arylsulfenyl NitrenesUp till now all attempts to synthesize organic thiazyl compounds in substance failed. Stabilization leads to the corresponding disulfide2, the thioaminyl radical7and the sulphur diimide8. Formally thiazyl compounds1and sulfenyl nitrenes1were resonance structures. Via sulfenyl nitrenes1the formation of2,7,8can be discussed. An in situ preparation of sulfenyl nitrene1avia the sulfenyl chloride5a, synthesized by chlorination of the disulfide2a, and the sulfenyl azide6ais described in detail.1acan also be prepared from the sulfenyl amide4aby oxidation. The structures of the radicals7a–fand12fare discusse

ISSN:0021-8383    

DOI:10.1002/prac.19873290111

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY