摘要:

AbstractThe total synthesis of lasiodiplodin via optically active sulfoxides and the preparation of polyenes through low valent titanium reagents are described.

ISSN:0009-4536    

DOI:10.1002/jccs.199000072

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractA purification procedure is described for preparing a heavy metal‐removed blank seawater without altering its major compositions and pH. Coastal seawater is treated sequentially by passing through a charcoal column, shaking with a dense slurry of ferric hydroxide at pH 8, and passing the surpernatant through a Chelex‐100 chelating ion‐exchange column. Experimental data show that this process efficiently removes Cd, Co, Cu, Cr(III), Fe, Mn, Ni, Pb, V and Zn from natural seawater at the spiking concentrations of 10 and 100 ppb l

ISSN:0009-4536    

DOI:10.1002/jccs.199000073

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractA series of biouclear copper (II) complexes containing a‐diimine ligand has been synthesized and characterized by electron paramagnetic resonance spectroscopy. The copper complexes of the form [Cu(dien)D](ClO4)2or [Cu2(dien)2L](CIO4)4, where dien is diethylenetriamine, L' is monodentate ligand and L is bridging ligand, were studied. The EPR spectra were recorded in solution and frozen glassy solution. In the frozen solution spectra, the values of G‖ are in the range of 2.10 to 2.20, and theg⊥ are in the range of 2.03 to 2.06. Furthesmore, the values of A‖ are in the range of 170 to 188 gauss, and the A ⊥ are in the range of 17 to 32 gauss. The data indicate that the structure of Cu(II) complexes is axial symmetry in square pyram

ISSN:0009-4536    

DOI:10.1002/jccs.199000074

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractReaction of the reactive carbanion with (η4‐cis‐l‐methoxy‐1,3‐butadiene)Fe(CO)3, followed by acid quenching, generates the C‐1 substitution product (27%) together with the regular C‐2 adduct (71%). A very stable ferracyclopentanone was isolated and its x‐ray diffraction ana

ISSN:0009-4536    

DOI:10.1002/jccs.199000075

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe concerted mechanism of phosphate‐catalyzed proton exchange in N,N'‐dimethylurea has been studied. Kinetic data were measured using the technigue of NMR line‐shape analysis. A significant kinetic isotope effect was observed for the concerted proton transfer in N,N'‐dimethylurea and is attributed to the tunnelling

ISSN:0009-4536    

DOI:10.1002/jccs.199000076

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractFourteen mass spectra of the sydnonylmethanols and their derivatives have been measured under EI conditions. The process of losing a OR' radical and hydrogen migration reaction are accompanyed with lost of a CO and an NO channel. The competition between cleavage of C‐0 bond and hydrogen migration is mainly controlled by the type and size of the R' grou

ISSN:0009-4536    

DOI:10.1002/jccs.199000077

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThree known furanocoumarins, imperatorin (1), wampetin (dehydroindicolactone) (2) and 8‐geranoxypsoralen (3) and a new sesquiterpene ketone, (+)‐oplopanone (4), were isolated fromClausena lansiumSkeels. The stereochemistry of the last two coumarins was determined by NOESY experiments. The idendity of (+)‐oplopanone was established by comparison of its physical constants and spectroscopic data with those reported for its enantiomer as well as a comparison of its' TLC behavior with that of an authentic s

ISSN:0009-4536    

DOI:10.1002/jccs.199000078

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractTwo new chemical resolution processes have been developed for the preparation of ( + )‐S‐2‐(6‐methoxy‐2‐naphthyl)‐propionic acid (d‐Naproxen). One is via the diastereoselective aminolysis of amide 4 with piperidine and the other is via the selective stoichiometric crystalliz

ISSN:0009-4536    

DOI:10.1002/jccs.199000079

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe total synthesis of natural antitumor agent (±) peperomin A, B and C are reported. These syntheses were started from benzophenones and diethyl succinate by Stobbe condensation. Three successive steps were employed to give the (±)‐peperom

ISSN:0009-4536    

DOI:10.1002/jccs.199000080

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractA synthesis of C18‐methyl‐β‐ionone (8) and C18‐methyl‐β‐ionylidenemalononitrile (13) is reported. Photoreaction of C18‐methyl‐β‐ionylidenemalononitrile resulted in a reversible 7‐cis and 7‐trans isomerization which eventually underwent 1,5‐Hydrogen shift to give the irreversible photoproduct, C18‐methyl‐y‐re

ISSN:0009-4536    

DOI:10.1002/jccs.199000081

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY