摘要:

AbstractA survey is given of the coordination chemistry of sulfurdiimines RNSNR and sulfinylanilines RNSO towards metal atoms. It is shown that these pseudoallene ligands which are isostructural and isoelectronic with SO2may coordinateviaN, S orviathe π‐NS double bond. Nitrogen coordination is favoured by metals in the higher oxidation statese.g.PtII, PdII, but may also occur for Rh1and If and even for zerovalent metals such as Cr°, Mo° and W°. Sulfur coordination probably occurs for Cr°, Mo° and W°, but has been observed for Rh1and Ir1. Finally, metal‐π‐N=S bonding is clearly favoured by electron‐rich metal atoms like Ni°, Pd°, Pt°, Rh1and Ir1. In the case of metal‐ π2‐N=S coordination of the RNSNR ligands further reactions may occur which lead to NS bond rupture. Such bond rupture may result in a large number of reactions varying from simple insertion of a metal atom into an N‐S bond to the formation of RNS, S and NR fragments which are captured in metal cluster complexes. Other ways of converting the RNSNR ligand involve the reactions with LiR′, R′MgX and trialkylaluminium compounds. The anionic RNS(R′)NR ligand so formed may behave as a bridging ligand but, more interestingly, as a pseudoallylic chelate group. It is shown that RNS(R′)NR−bonded as a chelate to transition metal atoms decomposes stereospe

ISSN:0165-0513    

DOI:10.1002/recl.19800990502

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractOrientation effects of electronegative substituents on vicinal carbon‐proton coupling constants are studied in 1,2‐disubstituted propanes and are found to resemble those on vicinal proton‐proton coupling constants. Known relations for the orientation effect of substituents on synclinal proton‐proton coupling constants can be modified so that they yield reasonable values for synclinal carbon‐proton coupling

ISSN:0165-0513    

DOI:10.1002/recl.19800990503

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractAn NMR investigation ofcisandtransisomers of styrylphenanthrene and some benzologues was performed, in which Δtrans‐cisvalues (δtrans‐δcis), temperature dependence (ΔT) in CS2and ASIS effects were determined. It was concluded that in the series styryl‐phenanthrene (2),‐benzo[c]‐phenanthrene (1),‐dibenzo[c,g]triphenylene (10),‐hexahelicene (9) only 1 exists mainly as acis‐synrotamer, whereas in the other compounds thecis‐antirotamer predominates in varying degrees. The introduction of an additional benzo group in 1 and 2 at the ring, containing the styryl substituent, which leads to the styryl‐chrysene (11) and styryl‐benzo[c]chrysene (12), shifts the conformational equilibrium to thecis‐synrotamer. The introduction of polar substituents at thepara‐position of 2‐styrylbenzo[c]phenanthrene has only a small influence on thesyn‐antiequilibrium. T

ISSN:0165-0513    

DOI:10.1002/recl.19800990504

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractQuantum‐chemical calculations are carried out on simplified models to obtain insight in the mechanistic aspects of coenzyme B

ISSN:0165-0513    

DOI:10.1002/recl.19800990505

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

Abstract(‐)‐3‐Hydroxy‐N‐methyl‐6‐oxomorphinan (6a) and its (‐)‐2‐bromo derivative (6b) were converted into (‐)‐2,3‐dihydroxy‐N‐methyl‐6‐oxomorphinan (8a) and its (‐)‐4‐bromo derivative (8b), respectively, by oxidation with Fremy's salt to theortho‐quinones, followed by reduction. Methylation of 8a and 8b gave the corresponding methyl ethers 9a and 9b. Catalytic hydrogenolysis of 8b and 9b gave 8a and 9a, respectively. The structure of (‐)‐2,3‐dimethoxy‐N‐methyl‐6‐oxomorphinan (9a) was confirmed by total synthesis, and that of (‐)‐4‐bromo‐2,3‐dimethoxy‐N‐methyl‐6‐oxomorphinan (9b) by single‐crystal X‐ray analysis.The model compound 2‐bromo‐

ISSN:0165-0513    

DOI:10.1002/recl.19800990506

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractA method is described for the calculation of reaction paths for the interconversion of conformers by forcing the internal rotation around one or more single bonds. The implementation of the method in a general computer program for molecular mechanics is discussed. It is shown that forcing the average of two or three torsion angles has distinct advantages. Results of calculations on the interconversion of the cyclohexane conformers are presented as an example.

ISSN:0165-0513    

DOI:10.1002/recl.19800990507

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

Abstract1,4‐Elimination of alcohols from ether of the type RO‐CH2‐C≡C‐CH2‐OR by treating these compounds with alkali amide, appears to be not a concerted process, but to proceed via short‐lived anions. These anions can be intercepted by ethyl bromide, present during

ISSN:0165-0513    

DOI:10.1002/recl.19800990508

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractA mechanistic model is presented for the conversion of right‐handed DNA into left‐handed DNA. In this model the co‐ordination of phosphorus plays a key

ISSN:0165-0513    

DOI:10.1002/recl.19800990509

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractA detailed mechanism is given for the isomerization of right‐handed DNA into left‐handed

ISSN:0165-0513    

DOI:10.1002/recl.19800990510

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19800990501

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY