Heterociklusos vegyületek szelektív szintézise telítetlen ketonok reakcióival = Selective synthesis of heterocyclic compounds by the reactions of unsaturated ketones

Kalkonok, (3-kumarinil)-kalkonok, valamint dehidroecetsavból nyert telítetlen ketonok és hidrazinok reakciójával új 2-pirazolinokat szintertizáltunk. E vizsgálatok körében kiemelendők a (karboxi-fenil)-hidrazinok és ezen telítetlen ketonok erekakciónak vizsgálatai és karboxilcsoportot tartalmazó 2-pirazolinok szintézise. Izoflavonok, homoizoflavonok és 4-tioanalogonjaik és hidrazinok reakciójával új pirazolokat szintetizáltunk, amelyek tautoméria viszonyait NMR-spektroszkópiai mérésekkel és kvantumkémiai számításokkal tanulmányoztuk. Racionális eljárást dolgoztunk ki új, exociklusos (E,E)-cinnamilidén-ketonok előállítására. E vegyületeket kiindulási anyagokként használtuk eddig ismeretlen sztiril-pirazolinok és tetraciklusos sztiril-1,5-benzotiazepinek előáálítására. Résztesen tanulmányztuk ezen telítetlen ketonok dimetildioxiránnal történő epoxidálását és az így nyert epoxidik sztereokémiáját. | New 2-pyrazolines have been synthesized by the reaction of chalcones, (3-coumarinyl)-chalcones and unsaturated ketones derived from dehydroacetic acid with hydrazines. Reactions of these unsaturated ketones with (carboxyphenyl)hydrazines for the preapartion of hitherto unknown (carboxyphenyl)-2-pyrazolines should be emphesized. New types of pyrazoles have been prepared by the reaction of isoflavones, homoisoflavones and their 4-thio analogues with hydrazines. Tautomerism of these new substances have been elucidated by NMR spectrsocopy and quantumchemical calculations. Versatile procedures were worked out for the synthesis of new exocyclic (E,E)-cinnamylideneketones. These substances were utilized as starting materials for the synthesis of hitherto unknown styrylpyrazolines and tetracyclic styryl-1,5-benzothiazepines. Epoxidation of these (E,E)-cinnamylideneketones with dimethyldioxirane has been achieved

Synthesis and structure elucidation of novel pyrazolyl-2-pyrazolines obtained by the reaction of 3-(3-aryl-3-oxopropenyl)chromen-4-ones with phenylhydrazine

Novel 3-aryl-5-{4-[5-(2-hydroxyphenyl)-1-phenylpyrazolyl]}-2-pyrazolines 2a-g have been prepared by the treatment of 3-(3-aryl-3-oxopropenyl)chromen-4-ones 1a-g with phenylhydrazine in refluxing acetic acid. NMR studies on deuteriochloroform solutions of pyrazolyl-2-pyrazolines 2a-g at different temperatures showed that at room temperature a mixture of diastereomers are present. This diastereoselectivity arises from the combination of the pyrazoline C-4 stereocenter and two planar chiral subunits due to internal steric hindrance. The energy barriers of this steric hindrance were overcome in DMSO-d6 solutions at 60oC. The acetylation of some pyrazolyl-2-pyrazoline derivativess 2a-c,e helped to confirm the presence of the referred mixture of diastereomers

Dimethyldioxirane oxidation of exocyclic (E,E)-cinnamylideneketones

http://apps.isiknowledge.com/full_record.do?product=UA&search_mode=GeneralSearch&qid=11&SID=X22NMCKHdF5lcLIJG6o&page=1&doc=1&colname=WOSExocyclic (E,E)-cinnamylideneketones were oxidized by an excess of isolated dimethyldioxirane (DMDO, in acetone solution) at room temperature, providing diastereomeric mixtures of the α,β:γ,δ-diepoxides. In the case of derivatives bearing an ortho-nitrocinnamylidene moiety, α,β-monoepoxides were also isolated as minor products. The structures of all new compounds and the stereochemistry of the monoepoxides and diepoxide diastereomers were established by NMR studies

Epoxidation of 2-Styrylchromone derivatives

2-Styrylchromones constitute a small group of natural heterocyclic compounds with significant biological properties. Certain natural and synthetic hydroxyl derivatives have shown important pharmacological and mainly antioxidant activities [1 ,2]. We are interested in the design of new 2-styrylchromones analogues containing hydroxyl groups at C-3 and in the Ca=C~ systems because they could increase the antioxidation activity of these type of compounds [2]. Our first approach is the preparation of epoxy systems and then we will try to open the epoxy ring to give the desired hydroxyl derivatives. We studied the epoxidation of 2-styryl-chromones 1 with hydrogen peroxide and iodosylbenzene using [salen Mn(lll)] as catalyst, and the epoxy products 2 were obtained in moderate yields. Since the best results were obtained with iodosylbenzene, we applied oxidant to compounds 3 in order to prepare 4. In this communication, we will report the synthetic details and the structural characterisation of the epoxides 3 and 4