摘要:

AbstractDissatisfaction with empirical methods, high expectations of the public, poorly harmonized international regulations, and rising costs have induced pharmaceutical research to search for new approaches. As a consequence, the medicinal chemist's professional activity is in a state of change. His synthetic strategy is being increasingly influenced by the reasoning of molecular biology. Novel classes of biologically active compounds demand the development of new synthetic methods beyond the scope of modern preparative organic chemistry: enzymes and microorganisms, cell cultures, and genetic engineering are harnessed to supply highly complex structures. Major efforts are devoted to the development of reliable structure‐activity relationships to rationalize his work. Thus the field of medicinal chemistry stretches from physical and physical organic chemistry far into the realm of biosciences, and the interdisciplinary character of this research is rapidly increasing. The author endeavors to convey an impression of this complex subject with the aid of selected example

ISSN:0570-0833    

DOI:10.1002/anie.198007493

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe thermal or photochemical denitrogenation of azoalkanes constitutes an effective and convenient method for the preparation of unusual organic molecules, including highly ringstrained, sterically crowded, fluxional, antiaromatic and other interesting structures. The importance of this synthetic approach is that the azo linkage serves as a means of introducing the critical (usually last) bond in the complex target molecule. This article presents a cross‐section of such elegant synthetic utilization of azoalkanes for fused‐, bridged‐ and spiro‐cyclization. Our coverage of the large body of literature has been directed by the complexity and novelty of the products. Azoalkanes are usually preparedviacycloaddition of azo dienophiles to appropriate sub

ISSN:0570-0833    

DOI:10.1002/anie.198007621

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractThe question of concerted or consecutive bond formation arises in all types of cycloaddition reactions. Stereochemical investigations and studies of regiospecificity as well as intensive kinetic investigations with regard to substituent and solvent effects, and the dependence of the reaction on temperature and pressure permit in many cases mechanistic conclusions concerning the Diels‐Alder reaction. Efforts towards a theoretical interpretation,ab initioand semiempirical calculations, the application of frontier molecular orbital theory (FMO) as well as thermochemical measurements permit a description of the energy hypersurface of these [4+2]‐cycloadditions. An attempt is made here to draw a line of distinction between the mechanistic alternatives—one‐step reactionversustwo‐step reaction—considering all experimental and theoretic

ISSN:0570-0833    

DOI:10.1002/anie.198007791

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198008071

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198008091

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198008101

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198008111

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198008121

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198008131

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.198008141

出版商:Hüthig&Wepf Verlag    

年代:1980

数据来源: WILEY