摘要:

Heterobimetallic Complexes Containing 2‐(Dimethylaminomethyl)ferrocenyl LigandsThe chemistry of heterobimetallic complexes containing the 2‐(dimethylaminomethyl)ferrocenyl ligand is reviewed, including main group element, transition metal, andf‐element derivatives. An overview on synthetic methods and molecular structures is

ISSN:0941-1216    

DOI:10.1002/prac.19983400502

出版商:WILEY‐VCH Verlag GmbH    

年代:1998

数据来源: WILEY

摘要:

Orthoamides. LI. Push‐Pull‐Butadienes and Heterocycles from Alkyne Carboxylic Acid Orthoamides and CH2‐acidic CompoundsThe acetylides4b, 4freact with N,N,N′,N′,N″,N″‐hexamethylguanidiniumchloride (5) to give the orthoamides6b, 6f, resp. From CH2‐acidic compounds and the orthoamides6a, c, ecan be obtained the push‐pull‐substituted butadienes8a–8aj. The 2,3,5‐trimethyl‐thiadiazolium salt9does not condense with6e, as other CH2‐acidic compounds do, instead the vinylogous guanidinium salt10ais produced. On heating, the ketenaminals8d, aacyclize to give the pyridone‐carbonitriles11a, b, resp. From 4‐amino‐coumarins12and the orthocarboxylic acid amideacetals13a, band the ketenaminal16resp., the amidines14a–cand the heterocyclic compounds15a–cresp., are formed. The enamines17a–c, 19a, breact with the orthoamides6a–fto give the pyridine derivatives18a–1, 20a–hand21a, b, resp. Analogously, from 6‐aminouracil22and6a, b, e, fare formed the pure 7‐dimethylaminopyrido[2,3‐d] pyrimidines23a, bor mixtures of compounds23c, dand the isomeric 4‐dimethylamino‐pyrido[2,3‐d]pyrimidines24a, bresp., which can be separated via their salts25a,b/26a,b. The heterocyclic compounds30a–d, 32a,bcan be prepared fro

ISSN:0941-1216    

DOI:10.1002/prac.19983400503

出版商:WILEY‐VCH Verlag GmbH    

年代:1998

数据来源: WILEY

摘要:

Synthesis of Ether‐bridged, Polycyclic Mono‐ and Bipyridines by Domino ReactionsOn the basis of iminium salt chemistry, an inexpensive one‐pot reaction provides novel ether‐bridged, polycyclic mono‐and bipyridines. This domino reaction sequence succeeds using chromanone derivatives and β‐amino ketone hydrochlorides (or free mannich bases) in the presence of ammonium acetate. The strategy offers a great flexibility in the design of new structures of this type (5a–b, 6a–cand8) and underlines the efficiency of

ISSN:0941-1216    

DOI:10.1002/prac.19983400504

出版商:WILEY‐VCH Verlag GmbH    

年代:1998

数据来源: WILEY

摘要:

AbstractThe cathodic reduction of dibenzofuran (2), 2‐chlorodibenzofuran (4), and 3‐chlorodibenzofuran (1) in deuterated methanol is investigated. The Birch‐type reduction product 1,4‐dibenzofuran (3) is formed from1via2, whereas 2‐chloro‐1,4‐dihydrodibenzofuran (5) is obtained as by‐product besides3from4as starting compound. Deuterium is only incorporated into the reduction products if CH3OD or CD3OD but not if CD3OH are used. This observation is strongly indicative of a polar mechanism involving protonation rather than a radical mechanism with hydrogen atom abstraction

ISSN:0941-1216    

DOI:10.1002/prac.19983400505

出版商:WILEY‐VCH Verlag GmbH    

年代:1998

数据来源: WILEY

摘要:

Abstract1‐Substituted 3‐hydroxy‐1H‐pyrazoles1react with chloroform, NaOH, and aceton resp. butan‐2‐one O‐regiospecifically to yield 2‐methyl‐2‐[(1H‐pyrazol‐3‐yl)oxy]‐propanoic resp. ‐butanoic acids14viaa dichlorocarbene (12)–dichlorooxirane (9) pathway. Chlorides17of14easily cyclize toN‐acylpyrazolium salts18/19, which quantitatively afford esters22–26and amides27–29of14. Enantiomers of the butanoic acid14th, obtainedviatheir diastereomeric cholesterol esters, differ in their stimulus to peroxisome proliferation. At 140 °C pyrazolium salts18undergo thermolysis to bicyclic β‐oxa‐γ‐lactams30–32. 3‐Carboxyisoalkylamino‐pyrazoles similarly give 1H‐β‐aza‐γ‐lactams34. Reactions of14with surplus SOCl2result in 6‐chloro‐37resp. 7‐chloro‐β‐oxa‐γ‐lactams38viachlorosulfinylation and extrusion of SO, and in 4,4‐bispyrazolyl‐sulfoxide39. A mild introduction of additional O‐functions into pyrazoles affording 4,5‐dihydro‐3‐hydroxy‐5‐oxo‐1H‐pyrazoles52–57is presented. Biological effects of the new pyrazoles are protection ag

ISSN:0941-1216    

DOI:10.1002/prac.19983400506

出版商:WILEY‐VCH Verlag GmbH    

年代:1998

数据来源: WILEY

摘要:

AbstractReductive dimerization of dodecylthio substituted 1,2‐dithiole‐3‐thiones6a–band trithion‐dithiacrown ethers10a–cwith triethyl phosphite furnished bis‐ and tetrakis (dodecylthio), and bis(dithiacrown ether) substituted thiodesaurines (E)‐11a–band (E)‐12a–c. The stereochemistry of bis(dithia[15]crown‐5)‐thiodesaurine (E)‐12bhas been determined by X‐

ISSN:0941-1216    

DOI:10.1002/prac.19983400507

出版商:WILEY‐VCH Verlag GmbH    

年代:1998

数据来源: WILEY

摘要:

AbstractThe regioselectivity of transannularO‐heterocyclization of cycloocta‐1,5‐diene (1) with phenylsulfenyl chloride and methanol or water, respectively, is determined by the oxy‐component which acts as nucleophilic partner in the electrophilic three component reaction. The thermodynamically more stableendo,endo‐2,6‐bis(phenylsulfenyl)‐9‐oxabicyclo[3.3.1]nonane (2) is formed almost exclusively in methanol while the isomeric 9‐oxabicyclo[4.2.1]nonane (3) is favored under kinetic control in the presence of water. The oxidation of2or3yields the bissulfones4a

ISSN:0941-1216    

DOI:10.1002/prac.19983400508

出版商:WILEY‐VCH Verlag GmbH    

年代:1998

数据来源: WILEY

摘要:

Two‐phase Hydroformylation of Buta‐1,3‐diene and Hydrocarbon Mixtures Containing Buta‐1,3‐dieneThe two‐phase hydroformylation of buta‐1,3‐diene with (HRh(CO)[P(m‐C6H4SO3Na)3]3the Kuntz catalyst system with excess P(m‐C6H4SO3Na)3) gives high yields of C5‐monoaldehydes. Main product in this mixture is the reactivetrans‐ andcis‐pent‐3‐enal. In consecutive reactions the pent‐3‐enal is partially hydrogenated ton‐pentanal, but also‐favoured by the protolytic milieu of the two‐phase reaction‐ aldol condensated to 2‐propenylheptadienal. The hydrogenation product of the propenylheptadienal, 2‐propylheptanol‐1, is a good plasticizer alcohol with a wanted low vapour pressure. Especially promising is the two‐phase hydroformylation of the unrefined C4‐fraction of the naphtha pyrolysis: after a more than 95 per cent conversion of the buta‐1,3‐diene also more than 80 per cent of then‐but‐1‐ene in the C4‐fraction is hydroformylated mainly to wantedn‐pentanal. Less than 5–10% of then‐but‐2‐enes and the isobutene in the C4‐fraction react under these conditions to oxo‐products (2‐ and 3‐methylbutanal). A

ISSN:0941-1216    

DOI:10.1002/prac.19983400509

出版商:WILEY‐VCH Verlag GmbH    

年代:1998

数据来源: WILEY

摘要:

Formaldehyde‐O‐oxide and Colchicine: An Elegant Route to the AllocolchicinesTropone is a structural unit of numerous natural productsi.e.imerubrine, harringtonolide and colchicine (2). It is of interest to study the selectivity of formaldehyde‐O‐oxide (1) with respect to these polyfunctional tropone derivatives. We report about the reactions of1with colchicine (2) and the colchicine derivatives5, 8, 11, 14, 17, 20under ozone free conditions. The fragmentation of the spiroozonides3, 6, 9, 12, 15, 18, 21viathe activated complexes3a, 6a, 9a, 12a, 15a, 18a, 21aopens up an elegant route to the allocolchicines4, 7, 10, 13,

ISSN:0941-1216    

DOI:10.1002/prac.19983400510

出版商:WILEY‐VCH Verlag GmbH    

年代:1998

数据来源: WILEY

摘要:

AbstractBenzyl cation inititiated intramolecular cyclization reactions with conjugated CC double bonds were performed providing rac.endo‐exoisomers of 1‐azabicyclo[3.2.1]octenes (2and3). Formation of theendoisomer2is favoured. Compounds2possess dopamine uptake inhibitory effect with an additional selective MAO‐B enzyme inhibitory potential. The remarkablein vitroeffects do not correspond toin vivoantidepressant a

ISSN:0941-1216    

DOI:10.1002/prac.19983400511

出版商:WILEY‐VCH Verlag GmbH    

年代:1998

数据来源: WILEY