摘要:

AbstractThe NMR spectra of alkyl‐substituted diphenylmethane derivatives have been measured. In each compound investigated all chemically equivalent protons or group of protons were magnetically non‐equivalent due to hindered rotation. The activation parameters for the rotation of the phenyl groups in 2,4,2′,4′‐tetra‐tert. butyl‐6,6′‐dimethyldiphenylacetic acid were determined from variable temperature NMR experiments and were found to be in good agreement with the activation parameters for the racemization. Due to decomposition no kinetic measurements could be made on the benzhydrols and the benzhyd

ISSN:0165-0513    

DOI:10.1002/recl.19700890702

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

Abstract4,6‐Diethoxy‐, 4‐ethoxy‐6‐hydrazino‐, 4,6‐dichloro‐, 4,6‐di(methylthio)‐and 4,6‐dihydrazinopyrimidine react with aqueous hydrazine at 210° to give 3‐methyl‐1,2,4‐triazole. Evidence is presented that in this unprecedented ring contraction reaction the C(2)‐N(3 or 1)‐C(4 or 6)‐C(5) fragment of the pyrimidine ring is involved in th

ISSN:0165-0513    

DOI:10.1002/recl.19700890703

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractThe preparation of the chlorosulfines RC(Cl)=S=O where R is C6H5and C6H5S, by oxidation of the corresponding thioacyl chlorides, is described. Reaction of these chlorosulfines with thiophenol and potassium thiocyanate leads to substitution of the chlorine atom giving phenylthio‐ and thiocyanosulfines, respectively. The displacement of the chlorine atom in chloro‐phenylsulfine by the phenylthio group occurs stereospecifically: the geometrical configuration of the chlorosulfine is predominantly retained in the product. A mechanism for these displacement reactions is propo

ISSN:0165-0513    

DOI:10.1002/recl.19700890704

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractDuring the reaction of aliphatic and aromaticC‐nitroso compounds (RNO) with benzenesulfinic acid, ESR spectra of alkyl and aryl benzenesulfonyl nitroxides (aNabout 12 gauss, g = 2.0060) have been observed. Unequivocal evidence for the structure R(C6H5SO2)NO* is found in an independent preparationin situby oxidation ofN‐alkyl‐ orN‐aryl‐benzenesulfonylhydroxylamines.Sulfonyl nitroxides are also generated by photolysis ofN‐methyl‐N‐nitrosotosylamide in hydrocarbons containing abstractable hydrogen atoms.A possible explanation for the rather large nitrogen hyperfine splitting constants of these nitroxid

ISSN:0165-0513    

DOI:10.1002/recl.19700890705

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractCyclopropanecarbaldehyde has been photolyzed in the gas phase with light in the 254 nm region. The most important gaseous products are carbon monoxide, ethene, propene and cyclopropane.The quantum yield of propene, which is almost independent of temperature, decreases with increasing aldehyde pressure but increases with increasing intensity of the absorbed light. The ratio of the yields of ethene and propene is independent of aldehyde pressure and absorbed light intensity, but increases with increasing temperatures. The quantum yield of cyclopropane increases both with increasing temperatures and increasing aldehyde pressure, but decreases with increasing absorbed light intensity.It is suggested that ethene and propene are formed by intramolecular decomposition from the same singlet excited state, whereas cyclopropane results from a radical decomposition of triplet aldehyde. The influence of the absorbed light intensity on the quantum yields of the gaseous products is explained in terms of triplet‐triplet annihilatio

ISSN:0165-0513    

DOI:10.1002/recl.19700890706

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractCyclopropanecarbaldehyde has been photolyzed in the gas phase with light of 254 nm, in the presence of each of the following hydrocarbons: neopentane, cyclohexane and 2,3‐dimethylbutane (biisopropyl). With increasing total pressure the quantum yields of the gaseous products carbon monoxide, ethene, propene and cyclopropane decrease. The decrease in the quantum yields of propene and ethene is explained in terms of collisional deactivation of vibration‐ally excited singlet excited cyclopropanecarbaldehyde.The decrease in the quantum yield of cyclopropane with increasing total pressure is explained partly in terms of collisional deactivation of vibrationally excited triplet cyclopropanecarbaldehyde, and partly in terms of hydrogen abstraction by cyclopropyl radicals from the added hydrocarbon. With 2,3‐dimethylbutane as addendum the two mechanisms are of about equal importance, whereas with neopentane or cyclohexane the former mechanism is thought to predom

ISSN:0165-0513    

DOI:10.1002/recl.19700890707

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractCyclopropanecarbaldehyde has been photolyzed in the gas phase with light of 313 nm and 254 nm in the presence ofcis‐2‐butene. With increasing total pressure the quantum yields of the gaseous products, carbon monoxide, ethene, propene and cyclopropane, decrease. The photolysis is accompanied by isomerization ofcis‐2‐butene totrans‐2‐butene, due to the transfer of triplet energy from the aldehyde to the olefin. The quantum yield of the 2‐butene triplet, ØBT, increases with increasing concentration of addedcis‐2‐butene. At a temperature of 50°, ØBTis about proportional to the concentration ofcis‐2‐butene. At a temperature of 150°, however, ØBTvery quickly reaches a constant value which is much lower for the photolysis with light of 313 nm (ØBT∼ 0.05) than for that wit

ISSN:0165-0513    

DOI:10.1002/recl.19700890708

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractIR and NMR spectral evidence indicates that α‐diazosulfones, RSO2CHN2(I), and α‐diazoketones, RCOCHN2(II), donate and accept protons in hydrogen bonding. The proton donor properties involve the methine proton as the donor site. The proton acceptor site is the sulfonyl group for α‐diazosulfones and the carbonyl moiety for α‐diazoketones. Using phenol as a donor molecule, OH stretching frequency shifts, Δν, have been measured for the α‐diazosulfones Ia‐Ig and the α‐diazoketones IIa‐IIf. Substituent effects on Δνvalues are modest for Ia‐Ig but more pronounced for IIa‐IIf. Compared with α‐diazoketones, α‐diazosulfones are stronger proton donors but weaker p

ISSN:0165-0513    

DOI:10.1002/recl.19700890709

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

Abstract3,5‐Dihydroxy‐2‐methyl‐5,6‐dihydropyran‐4‐one was prepared in reasonable yield fromD‐glucose and piperidine salts. Of the possible mechanisms, experimental evidence favours that involving conversion of the resulting aldosylamine into the enol of the corresponding aminodeoxyketose (Amadori rearrangement), followed by 1,4‐elimination of amine from this enol and subsequent acid‐ca

ISSN:0165-0513    

DOI:10.1002/recl.19700890710

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY

摘要:

AbstractThe observed Raman and infrared spectra of AsBr3in the solid and liquid states are assigned; for the solid state according to the space group D42of the crystal.

ISSN:0165-0513    

DOI:10.1002/recl.19700890711

出版商:WILEY‐VCH Verlag    

年代:1970

数据来源: WILEY