摘要:

AbstractA new numerical method for isolating component spectra from spectra of their mixtures is presented. The method searches the component spectra by optimizing a risk function which assigns a relative value for the risk to regard a spectral shape as that of a pure substance. No prior knowledge of the nature of existing components is required in the analysis. All components conceivable in the set of mixture spectra are simultaneously isolated.

ISSN:0009-4536    

DOI:10.1002/jccs.197800029

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractIn studies of the phosphorylated proteins in Walker‐256 carcinosarcoma, it was established that the ratio of P‐N linkages to P‐O linkages on histone H1varied between 0.6 to 1.0. Histone H1was phosphorylated in vivo and isolated under all neutral conditions employing a dextran/polyethylene glycol two‐phase system and Bio‐Rex 70 chrom

ISSN:0009-4536    

DOI:10.1002/jccs.197800030

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractThe proton nmr isotropic shifts of pyridine type ligands coordinated to paramagnetic nickel(II) and cobalt(II) acetylacetonate are reported, and the mechanisms of unpaired electron spin delocalization in these complexes are discussed. It is found that a σ‐delocalization mechanism is in dominant, but the π‐contribution can not be rule out. The calculations of the geometric factor for Co(II) complexes are done. It is used in the ratio method to separate the contribution of pseudo‐contact shift from isotropic shift for Co(II) complexes. The effect of pseudoaromatic chelate ring on contact shift is not so large as previously r

ISSN:0009-4536    

DOI:10.1002/jccs.197800031

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractThe axial CD spectra of single crystal of Zn(en)3(NO3)2doped with 1‐50% Ni(en)3(NO3)2have been observed at temperatures from ambient to 5 K. The increase in R of the3E[3T3g(F)] transition as the temperature decreases is consistent with the magnetic dipole allowed character of the parent octahedral transition. The electric and magnetic dipole forbidden transition to the3T1g(F) octahedral level gives rise to a relatively weak axial CD band with an unusual temperature dependent splitting. This structure is attributed to electric quadrupole intensity, which is allowed for transitions to both the E and3A2[3T1g(F)] levels in D3symmetr

ISSN:0009-4536    

DOI:10.1002/jccs.197800032

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractThe reactions of oligomeric difluorosilylenes withcis‐andtrans‐difluoroethylene are studied. All six new products are characterized and the stereochemistry suggests an integrated reaction mechanism in which both addition and insertion pathways share a common diradical transition st

ISSN:0009-4536    

DOI:10.1002/jccs.197800033

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractD(‐)‐Ephedrine was prepared by resolving the racemate through its N‐benzyloxycarbonyl‐L‐phenylalanine salt in ether solution. The L(+)‐ephedrine in mother liquid was recovered and precipitated exclusivly withN‐benzyloxycarbonyl‐L‐alanine in ethyl acetate. The amino acid derivatives were recovered from the salts by acid decomposition and the optically pure ephedrine was also recovered, which was again useful for the resolution of racemic amino acid derivatives synthesized chemically. Other amino acid derivatves are also tested for the mutual resolution.Mutual resolution was also effected by dissolving DL‐ephedrine andN‐benzyloxycarbonyl‐DL‐alanine in ethyl acetate to obtain the optically pure D(‐)‐ephedrine and

ISSN:0009-4536    

DOI:10.1002/jccs.197800034

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractEighteen Z‐X‐Y‐OTNB+type dipeptides, four Z‐Val‐Cys(Bzl)‐X‐OTMB tripeptides and a tetrapeptide Z‐Val‐Cys(Bzl)‐Cys(Bzl)‐Asn‐OTMB have been synthesized by papain‐catalyzed reaction in reasonable yield after recystallization. Z‐DL‐Ala‐OH has been resolved through papain‐catalyzed synthesis of Z‐L‐Ala‐Leu‐OTMB with an optical purity as high as 98.6%. These results show that papain is a

ISSN:0009-4536    

DOI:10.1002/jccs.197800035

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractThis is to report a study in which cation ion‐exchange resin serves as the stationary phase for liquid chromatography of benzoic acid and phthalic acid and aqueous ethanol acts as the mobile phase. No ion. exchange phenomenon is involved. It is rather a solvent action on the polymer matrix for the organic solutes. It was found that the elution volumes depend on thepKavalues of the acids; the higher thepKavalue the more the retention volum

ISSN:0009-4536    

DOI:10.1002/jccs.197800036

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY

摘要:

AbstractThermal transesterification of phenylurethane with n‐octanol was carried out in DMSO. It was found that the reaction followed first‐order kinetics with an average rate constant of 8.630 × 10−5sec−1at 140°C. High pressure liquid chromatograph technique was employed to analyze chemical species in the course of the reaction. The reaction obeyed Arrhenius equation closely between 133°C and 155°C with activation energy of 29.6 kcal/mole and entropy of activation of −8.2cal/moledeg at 140°C. An intramolecular cyclic intermediate mechanism was proposed for

ISSN:0009-4536    

DOI:10.1002/jccs.197800037

出版商:WILEY‐VCH Verlag    

年代:1978

数据来源: WILEY