摘要:

AbstractThe NMR spectrum ofN‐(benzyloxycarbonyl)‐L‐prolinet‐butyl ester shows twot‐butyl signals of slowly interconvertingsynandantirotamers. Thet‐butyl signals have been assigned to thesynand theantiform by using Eu(fod), as a shift reagent. The thermodynamic parameters ΔG≠, ΔH≠and ΔS≠for rotation about the amide bond have been determined by the method ofShanan — AtidiandBar‐Eliand by complete line shape analysis, in four solvents of different polarity. T

ISSN:0165-0513    

DOI:10.1002/recl.19750940602

出版商:WILEY‐VCH Verlag    

年代:1975

数据来源: WILEY

摘要:

Abstract4‐Methylprotoadamant‐4‐en‐2‐one was isolated from the reaction of 1‐methyladamantan‐2‐one with sodium azide and methanesulfonic acid. A side product of this reaction is probably 4‐methylenepro

ISSN:0165-0513    

DOI:10.1002/recl.19750940603

出版商:WILEY‐VCH Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractFrom the P.M.R. spectra of phenylcyclopentadienide anion and of phenyltropylium cation it is concluded that the proportionality factor between the proton chemical shift and the charge density of 10 ppm per unit charge is not well founded.

ISSN:0165-0513    

DOI:10.1002/recl.19750940604

出版商:WILEY‐VCH Verlag    

年代:1975

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19750940605

出版商:WILEY‐VCH Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractFourier transform carbon‐13 NMR spectra of a series of 3‐(X‐phenyl)glutaric anhydrides [X: H (2),4‐F (3), 4‐Cl (4), 4‐Br (5), 4‐OCH3(6), 4‐NO2(7), 3‐Cl (8) and 2,6‐Cl2(9)] and of 3‐methyl‐3‐(4‐chlorophenyl)‐ (10)‐, 3,3‐diphenyl‐ (11)‐ and 3,3‐(2,2′‐biphenylylene)‐glutaric anhydride (12) have been obtained and interpreted. Spectral assignments of the aromatic side‐chain carbons for3–9were made with the aid of additive parameters derived from suitably substituted toluenes for which unequivocal assignments are possible. The carbon‐13 and proton chemical shift data of the glutaric anhydride skeletal carbons and appended protons are compared and discussed in terms of conformational properties of the anhydride ring and its side‐chain. A set of substituent parameters (α: 17.6 ± 0.3 ppm, β: +7.0 ± 0.3 ppm and γ: −1.3 ± 0.3 ppm), which correlates the average effect of the XC6H4nucleus on the chemical shifts of the

ISSN:0165-0513    

DOI:10.1002/recl.19750940606

出版商:WILEY‐VCH Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractThe comparison of the rates of chromic oxydation of 2‐adamantanol, bicyclo[3.3.1]nonan‐9‐ol andcisandtrans4‐tert‐butylcyclohexanols shows that the transition state of this reaction is product‐like.It appears that 1,3 diaxial interactions increase, according to the system, in the following order: cyclohexyl

ISSN:0165-0513    

DOI:10.1002/recl.19750940607

出版商:WILEY‐VCH Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractSeveralS,N‐protected‐2‐mercapto‐2‐aminopropionic acid derivatives (3a‐gTable I) have been prepared by the reaction of thiols with the correspondingN‐protected 2‐hydroxy‐2‐amino‐propionic acid derivatives8, prepared from the corresponding amides7and pyruvic acid. Recent controversies in the literature regarding this method are discussed. Selective removal of the sulfur‐protecting group in3band3eafforded the 2‐mercapto‐2‐acylamidopropionic acids11, R2= H and C6H5respectively. Reaction of3ewith thionyl chloride afforded 4‐methyl‐4‐(acetylthio)‐2‐phenyl‐2‐oxazolin‐5‐one10. Under

ISSN:0165-0513    

DOI:10.1002/recl.19750940608

出版商:WILEY‐VCH Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractTwo routes for the synthesis of monodesthiosecogliotoxin analogues4are described. The addition of suitableN‐protected α‐mercapto α‐amino acids to ethyl 3H‐indole‐2‐carboxylates followed by removal of the amino‐protecting group provides a convenient approach to the title compound. Illustrative of this, the adduct of ethyl 3,3‐dimethyl‐3H‐indole‐2‐carboxylate8with 2‐mercapto‐2‐(benzyloxycarbonylamido)propionic acid11, which was preparedin situfrom the mercaptoacetylated precursor12, gave17after deprotection of the amino group.Asimple alternative route starts with bromination of the thiazolidinone13withN‐bromosuccinimide to yield29. Substitution of the bromine with an azido group yielded the imino compound32directly; this could then be reduced with NaCNBH3giving the

ISSN:0165-0513    

DOI:10.1002/recl.19750940609

出版商:WILEY‐VCH Verlag    

年代:1975

数据来源: WILEY

摘要:

AbstractNormal coordinate calculations ofcis‐ andtrans‐CHFCHF and of CF2CH2have been undertaken using Modified Valence Force Fields based on vibrational data of all the hydrogen and deuterium isotopes. A definite vibrational assignment is given for CF2CH2based on new infrared and Raman gas phase spectra.The calculated valence force fields ofcis‐ andtrans‐difluoroethylene. vinylidene fluoride and the vinyl halides mutually ag

ISSN:0165-0513    

DOI:10.1002/recl.19750940610

出版商:WILEY‐VCH Verlag    

年代:1975

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19750940601

出版商:WILEY‐VCH Verlag    

年代:1975

数据来源: WILEY