Studies On DMP/Bu₄NX For Oxidation And Halogenation Of Anilines And Terminal Alkynes And The Cyclization Of3-Alkyl-1-Aryl-1H-Pyrazol-5（4H）-Ones

Hypervalent iodine（Ⅴ） compound DMP regarded as a kind of mild and highlychemical selectivity oxidation regent have wide applications in the field of organicsynthesis. In this thesis, a more comprehensive review summarized the applications ofDMP reagent in the field of organic synthesis in the last twenty years, and there arelots of reaction examples to illustrate the incomparable important position ofhypervalent iodine compound in the organic synthesis.In recent years, Nitrogen-containing heterocycles occupied a very importantposition in pharmaceutical, pesticide research, especially pyrazolone compounds.5-Pyrazolone derivatives have a broad spectrum of biological activities and asignificant pharmacological properties being analgesic, antipyretic andanti-inflammatory therapeutical drugs.3-methyl-1-phenyl-1H-pyrazol-5（4H）-one isan important class of heterocyclic compounds with physiological activity and a higherchemical reactivity. In particular, the C4position of it has a high negative charge, isprone to take nucleophilic reactions for the formation of C4substituted derivatives,which are mainly used for the preparation of intermediates for pyrazolone dyes anddrugs.A new synthetic investigation on oxidation of anilines with DMP to formiminoquinones under very mild conditions by our group, when tetrabutyl ammoniumbromide was added in the reaction system,2-amino-[1,4]-benzoquinone-4-phenylimides could be further functioned. Thereby increasing the scope of DMPassisted transformation extensively. In this paper, we wish to report the detail studyingresults of the combination of DMP and TBAB, TBAC, TBAF, TBAI leads to theformation of the structurally diversified iminoquinones. In the course of studying themechanism of this reaction, we postulated Bu₄N+X-（OAc）₂as key intermediateaffording from the reaction of TBAX and DMP, which was utilized as Halogenationreagent to further halogenate the iminoquinones underwent the electrophilic additionprocess.It was well known that intermediate Bu₄N+X-（OAc）₂has been used aselectrophilic reagents for displacement of hydrogen atom of the terminal alkyne.Alkynyl halides are increasing importance as versatile building blocks in transition metal-catalyzed cross-coupling reaction. In this paper, we set up a second set ofexperiments using quaternary ammonium salts and DMP system for the facilepreparation of organic halides suitable for this synthetic purpose. The results foundthat better result was obtained in the case of TBAI giving the iodinated alkynes withexcellent yield. To our delight that the Glaser coupling reaction of terminal alkyneswas achieved under aqueous phase and wool-Pd（Ⅱ） complexes as catalyst.In this part, we have conducted a synthetic investigation on the reaction of3-alkyl-1-aryl-1H-pyrazol-5（4H）-one with DMSO in the presence of NaAc·3H₂O asbase using LiBr·H₂O as additive and developed a successful protocol of synthesis of anew class of octatomic ring compounds. The structure of the newly-found compoundsis confirmed by single crystal diffraction analysis; the possible mechanism also ispostulated.The innovation points of this paper:1. A series of halogenated iminoquinone derivatives were synthetized, which haspotential value in the field of medicine;2. Bu₄N+X-（OAc）₂as electrophilic reagents applied for the halogenation ofterminal alkynes, and the Glaser coupling reaction of terminal alkynes in water mediausing wool-Pd（Ⅱ） complexes as catalyst.3. A structurally diversified pyrazolone compounds library was established viathe reaction of3-alkyl-1-aryl-1H-pyrazol-5（4H）-ones under relatively mildconditions.