摘要:

AbstractThe photooxygenation of 3,4‐dihydro‐2H‐pyran sensitized by cyanoanthracenes (9,10‐dicyanoanthracene and 9‐cyanoanthracene) in different solvents (CH3CN, CH3Cl2,C6H6and CCl4) has been studied in this paper. The products, product distribution as well as solvent isotope effect are the same as those in the reaction of singlet oxygen. Fluorescence quenching, exciplex formation and free energy change also reveal that electron transfer occurs between sensitizer‐excited singlet state and substrate and then singlet oxygen is formed subsequently as the reactive intermediate in

ISSN:0256-7660    

DOI:10.1002/cjoc.19860040102

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractOn the basis of the experimental data reported in literature, the contributions of cation mass (m) and molar volume (V) to lattice heat capacity (C) were analyzed. The volumetric‐mass formula,Cx=(l —f)·C1+f·C2+Cm·(mx—mx′), was presented for estimating the heat capacities of rare‐earth compounds. In the formulaC1andC2represent the lattice heat capacities of two reference substances respectively,f=Vx—V1/V2—V1andCmrepresents the lattice heat capacity variation with the variation 1 g of cation mass. The equation relating theCmwith temperatures was derived as follows:Cm= 0.084e−0.0074T−0.27e−0.045T, andmxandmx′ (= (1 ‐f)m1+fm2) represent the practical and “assumed” cation masses of the subs

ISSN:0256-7660    

DOI:10.1002/cjoc.19860040103

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe reaction of vinylmagnesium bromide (1) with trityl chloride (2) was investigated and the products were identified as triphenylmethane (3) (81 %), acetylene (4) (74%), trityl peroxide (6) (4%), and minute amounts of triphenylpropene (7) andp‐diphenylmethyltetraphenylmethane (8). The results indicate that 1 possesses reducing property. The reaction mixture showed an ESR spectrum identical with that for trityl radical and the CIDNP of enhanced absorption for4‐Hof l‐diphenylmethylene‐4‐trityl‐2,5‐cyclohexadiene (9). Trapping experiment with styrene decreased the amount of3but had no effect on the formation of4.The reducing property of 1 is discussed and one electron transfer mechanism for the reaction of1with2is proposed.S‐T0mixing between trityl and·MgBr occurred and the coupling of polarized trityl radical with another trityl radical resulted in the formation of polarized dimeric product. The different character between the reaction of1and2and that of1and diphenylmethyl chloride (10) may be rationalized by the different electron‐accepting abilities between2and10.The origin of CIDNP effect shown by the product tetraphenylethane (11) for the reaction of1with10is also explained according to K

ISSN:0256-7660    

DOI:10.1002/cjoc.19860040104

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractFive newbis(β‐carbomethoxyethyl)tin derivatives including R2Sn(acac)2(R = CH2OCOCH2CH2), R1Sn(dbm)2,R2SnO, R′2Sn(dbm)2[R′=CH2OCOCH(CH3)CH2] and R′SnO were synthesized. The structures of these compounds were compared with R2SnCl2,R′2SnCl2,(C2H17)2SnCl2,and (C2H17)2Sn(OCOC11H2)2.H NMR, IR and Mössbauer spectroscopic data showed that R′2Sn(dbm)2contains acisC‐Sn‐C unit, (C2H17)2Sn(OCOC11H23)3exists as a mixture of two isomers, while the other compounds have

ISSN:0256-7660    

DOI:10.1002/cjoc.19860040105

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractMass spectra of thirteen epimers of podophyllotoxin and its derivatives have been examined. By means of high resolution mass spectrometry, metastable ion scanning and isotopelabeling techniques, the effects of configuration of C1‐OH and condensed lactone ring on the fragmentation pattern and the relative abundances of characteristic ions in the mass spectra of these compounds have been studied and rationalize

ISSN:0256-7660    

DOI:10.1002/cjoc.19860040106

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractIR and Raman spectra of [Mo2O2S2(S2)2]2‐were reported. The resonance Raman spectra and the depolarization ratios in CH3CN solution were measured. By using the data of crystal structure, the simplified normal coordinate calculation of the stretching vibrations for anion [Mo2O2S2(S2)2]2‐was performed. The results obtained are useful to assign the vibrational bands of some Mo‐Fe‐S c

ISSN:0256-7660    

DOI:10.1002/cjoc.19860040107

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractNatural maytansinoids and their synthetic intermediates (1—9) were studied by means of mass spectrometry upon electron impact condition. The fragmentation pathway and spectra‐structural relationship of these compounds were proposed. Based on the fragmentation pattern, structures of the synthetic analogs were identif

ISSN:0256-7660    

DOI:10.1002/cjoc.19860040108

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

Abstract(±)‐Fangchinoline was synthesized by condensation of (±)‐1‐(3‐bromo‐4‐methoxy‐benzyl)‐2‐methyl‐6‐methoxy‐7‐hydroxy‐8‐bromo‐1,2,3,4‐tetrahydroisoquinoline (2) and (±)‐1‐(4‐hydroxy‐benzyl)‐2‐methyl‐6‐methoxy‐7‐hydroxy‐1,2,3,4‐tetrahydroisoquinoline (3)

ISSN:0256-7660    

DOI:10.1002/cjoc.19860040109

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractNine known compounds, 5‐hydroxy‐4′,7‐dimethoxy‐6,8‐dimethylflavone, 4′,5‐dihydroxy‐7‐methoxy‐6,8‐dimethylflavone, 3β‐hydroxy‐urs‐11‐ene‐28‐oic‐13(28)‐lactone, 3β‐acetoxy‐urs‐11‐ene‐28‐oic‐13(28)‐lactone, uvaol, β‐sitosterol, 7β‐O‐glucoside of 5,7‐dihydroxy‐2‐methylchromone, 1‐triacontanol and 1‐triacontanoic acid, and a new acylphloroglucinol named robustaol B 6 were isolated from the leaves ofEucalyptus robustaSm.6was shown to be 4,6‐dihydroxy‐2‐methoxy isobutyrophenone by spectral analyses and was confirmed by synthesis.6sh

ISSN:0256-7660    

DOI:10.1002/cjoc.19860040110

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractUsing PTC or cosolvent, both perfluoroalkyl bromides such as Br (CF2)2O(CF2)2SO2Na (1), Br(CF2)2OCF2CO2H (2), Cl(CF2)4Br (3), Cl(CF2Br (4),n‐C6F13Br (5),n‐C8F17Br (6), H(CF2)8Br (7), α, ω‐dibromides O(CF2CF2Br)2(8), Br(CF2)6Br (9) and Br(CF2)8Br (10) reacted readily with Na2S2O4in the presence of NaHCO3in aqueous solution to form the corresponding perfluoroalkane sulfinates NaO2S(CF2)2O(CF2)2SO2Na (11), NaO2S(CF2)2OCF2CO2Na (12), Cl(CF2)4SO2Na (13), Cl(CF2)2SO2Na (14),n‐C3F13SO2Na (15),n‐C8F17SO2Na (16), H(CF2)8SO2Na (17), α, ω‐disulfinates O(CF2CF2SO2Na)2(18), NaO2S(CF2)4SO2Na (19) and NaO2S(CF2)8SO2Na (20) in 66—97% yields. To this new and general reaction of perfluoroalkyl bromides, the name sulfinatodebromin

ISSN:0256-7660    

DOI:10.1002/cjoc.19860040111

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY