摘要:

AbstractThe heats of formation of octahedrally coordinated complexes of O‐containing ligands follow a relationship, proposed earlier\documentclass{article}\pagestyle{empty}\begin{document}$$ -{\rm U = C}_{\rm L} + {\rm I - n}_{\rm e} \Delta _{\rm L}$$\end{document}while those of N‐containing ligands follow a more involved equation\documentclass{article}\pagestyle{empty}\begin{document}$$ -{\rm U = C}_{\rm L} + {\rm I + n}_{\rm t} \gamma _{\rm L} - {\rm n}_e \Delta _{\rm L} $$\end{document}where I‐the ionization potential (I1+ I2of the atom, CL, ΔLand γLare constants dependent on the ligand, while ntand neare the number of 3d‐electrons in the t2gand the eg‐antibonding orbitals. For O‐ligands, as for those ligands discussed previously ΔL∼ Δs(spectroscopic ligand field splitting factor), while for N‐ligands, (ΔL+ γL) ∼ Δs. It is proposed that γLrepresents the depression in energy of the t2g‐levels by acceptor π‐bonding connected with a 3p‐orbital of atomic N: it is numerically equal to 6 kcal/at for a central ion with an environment of 6 N‐atoms.The ΔLand CL‐values for O‐ and N‐containing ligands appear almost equal, suggesting t

ISSN:0165-0513    

DOI:10.1002/recl.19640830102

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractTheoretical and practical aspects of square wave conductometry are discussed. Equilibrium conditions for a simple bridge circuit are compared with those for classical sine wave conductometry. It is shown that square wave conductometry is less dependent on the choice of the cell parameters.As an example, square wave conductometry is applied to the titration of hydrochloric acid and acetic acid with sodium hydroxide, using both wire and plane electrodes. The influence of the presence of a redox couple upon the equilibrium condition appears to be negligible in square wave conductometry.

ISSN:0165-0513    

DOI:10.1002/recl.19640830103

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

Abstract6‐Phenyl‐2‐pyrone‐3‐carboxylic acid has been prepared by acid hydrolysis of its ethyl ester and by the action of sulfuric acid on its isomer, 2‐carboxy‐5‐phenyl‐2‐penten‐4‐yn‐1‐oic acid. The distinction between these two isomers and a third, 2‐carboxy‐5‐phenyl‐2,4‐pentadien‐(1,4)olide, is set forth. A fourth isomer, 3‐phenyl‐2‐pyrone‐6‐carboxylic acid, has been synthesized by acid hydrolysis and

ISSN:0165-0513    

DOI:10.1002/recl.19640830104

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

By reaction of triacetic lactone with phosphoryl chloride 4‐chloro‐6‐methyl‐2‐pyrone was prepared; this happened to be identical with a compound of uncertain structure, previously obtained from acetyl chloride and 1,1‐dichloroethene. Reductive dechlorination yielded 6‐methyl‐2‐pyrone.Both 6‐cyclopentyl‐3‐cyclopentylcarbonyl‐4‐hydroxy‐2‐pyrone and 6‐cyclopentyl‐4‐hydroxy‐2‐pyrone were prepared by conventional methods; they have bacteriostatic properties. By chlorination and reduction of the latter compound 6‐cyclopentyl‐2‐pyrone was obtained.The mechani

ISSN:0165-0513    

DOI:10.1002/recl.19640830105

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19640830106

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractA synthesis is described of a protected pentapeptide, in which the amino‐acid sequenceL‐alanyl‐D‐glutamyl‐L‐lysyl‐D‐alanyl‐D‐alanine, found in bacterial cell wall substances, is present. By the nature of its amino‐ and carboxyl‐protecting groups it seems suitable for condensation withN‐acetylmurami

ISSN:0165-0513    

DOI:10.1002/recl.19640830107

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractInvestigations are described on selective bromination of tertiary hydrogen atoms in alicyclic compounds by radical halogenation with molecular bromine.Isopropylcyclopentane, isopropylcyclohexane, bicyclopentyl and bicyclohexyl have been chosen as simple model systems.From the first two compounds the corresponding di‐tertiary 1,6‐dibromoisopropylcyclopentane and 1,7‐dibromoisopropylcyclohexane, respectively, were obtained in good yields.The structure of both these substances has been elucidated by degradation reactions as well as by independent syntheses; N.M.R.‐spectra also provide confirmatory evidence for the structures assigned to the di‐tertiary dibromo compounds.The tertiary hydrogen atoms in bicyclopentyl and bicyclohexyl cannot be brominated selectively; in both cases higher brominated compounds are obtained as the main

ISSN:0165-0513    

DOI:10.1002/recl.19640830108

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractRing closure of 2‐alkoxyethyl diazomethyl ketones (VII) under the influence of a catalytic amount of hydrochloric acid gives 3‐ketotetrahydrofuran (VIII). The yields obtained in this reaction are greatly influenced by the choice of the alkoxy group. 3‐Ketotetrahydrothiophen (XX) is prepared from 2‐tert.butylthioethyl diazomethyl ketone (XIXa) by the same pr

ISSN:0165-0513    

DOI:10.1002/recl.19640830109

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractA mechanism for the formation of 10‐D‐chlorosulphoxide‐camphor is proposed and its meaning for a possible preparation of thioaldehyde and thioketone oxides put fo

ISSN:0165-0513    

DOI:10.1002/recl.19640830110

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe synthesis is described of a mixed‐acid phosphatidylserine, containing one saturated and one unsaturated fatty acid, by a reaction between γ,β‐diacylglycerol‐L‐α‐iodohydrin and silverN‐t. butoxycarbonyl‐O‐(O‐benzylphospho)‐DL‐serine t. butyl ester.Some physical and biochemical properties of the unsaturated phosphatidylserine,viz. (γ‐oleoyl‐β‐palmitoyl)‐L

ISSN:0165-0513    

DOI:10.1002/recl.19640830111

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY