Polifunkcionalizált alifás és heterociklusos vegyületek új, alfa-azidoketonokból kiinduló szintézismódszereinek kifejlesztése = Development of new methodologies for the synthesis of polyfunctionalized aliphatic and heterocyclic compounds from alpha-azidoketones

További szintetikus bizonyítékokkal támasztottuk alá az alfa-azido-ketonokból nyerhető karbanionok és imid anionok alkalmazhatóságát több funkciós csoportot tartalmazó szintetikus építőkövek és különböző heterociklusos vegyületek előállítására. Ezek az új metodológiák bonyolultabb szerkezetű kiindulási anyagok esetén számos, eddig ismeretlen vegyületcsalád, köztük 4-aroil-3-azido-2-butenoátok, 3-aroil-2H-azirin-2-karbonsav észterek, 5-hidroxi-2,5-dihidrooxazol-4-karbonsav észterek és 2-aroilamino-3-oxoalkánsav észterek elérését teszik lehetővé. Javaslatot tettünk ez utóbbi vegyületek nemvárt, anomális képződési reakciójának mechanizmusára. Hatékony redukciós módszereket fejlesztettünk ki és megoldottuk a labilis alfa-aminoketonok elfogását és védett származékká alakítását. Hatékony és általános módszert dolgoztunk ki 3-amino-kromonok és 2-alkilezett származékaik szintézisére. Megállapítottuk, hogy az 1,3-dipoláris cikloaddíció alkalmas alfa-(1,2,3-triazolil)-ketonok előállítására. A Sharpless-Meldal-féle ''click'' reakció alfa-hidrogént tartalmazó alfa-azido-ketonok esetén a kívánt triazolokat adta, de eredménytelennek bizonyult az alfa-azido-alfa,béta-telítetlen ketonok esetében. Ez utóbbi vegyületeket a Huisgen-féle termikus reakcióval sikerült triazolokká alakítani. | We have added further synthetic proofs to the usefulness of carbanions and imide anions prepared from alfa-azido ketones in the synthesis of multifunctionalized building blocks and various heterocycles. Using more complex starting materials these new synthetic methodologies allowed the preparation of several hitherto unknown compound classes including 4-aroyl-3-azido-2-butenoates, 3-aroyl-2H-azirin-2-carboxylates, 5-hydroxy-2,5-dihydrooxazol-4-carboxylates and 2-aroylamino-3-oxoalkanoates. These latter products were formed in an anomalous reaction, a mechanism to interpret the unexpected transformation was suggested. Efficient reduction methods have been developed and the obtained unstable alfa-aminoketones were successfully trapped in protected form. Efficient and general method has been found for the synthesis of 3-aminochromones and their 2-alkyl derivatives. 1,3-dipolar cycloaddition reactions proved to be useful tools for the synthesis of alfa-(1,2,3-triazolyl)ketones. The Sharpless-Meldal's ''click'' reaction gave the desired triazoles when alfa-azido ketones with alfa-hydrogen were used as starting materials but failed to yield any product in the case of alfa-azido-alfa,beta-unsaturated ketones. These latter substrates were transformed into their triazoles by using Huisgens's thermal conditions

Application of Carbohydrates with Methylene or Vinyl Groups in Heck–Mizoroki Cross-Coupling Reactions with O-Heterocycles

Structurally novel carbohydrate–O-heterocycle derivatives linked by various unsaturated carbon bridges were synthesized by palladium-catalyzed cross-coupling reactions

Synthesis of 8-Bromoflavone and its Buchwald-Hartwig Reaction

Simple and convenient synthesis of 8-bromoflavone was achieved, starting from 2-bromophenol through 3’-bromo-2’-hydroxyacetophenone whose preparation was managed to be solved by optimized Fries rearrangement. The Buchwald-Hartwig reaction of 8-bromoflavone with different type of primary and secondary amines was carried ou

Regioselective Suzuki–Miyaura Cross-Coupling Reactions of the Bis(triflate) of 1,4-Dihydroxy-9H-fluoren-9-one

1,4-Diaryl-9H-fluoren-9-ones were prepared by regioselective Suzuki–Miyaura cross-coupling reaction of the bis(triflate) of 1,4-dihydroxy-9H-fluoren-9-one. The reactions proceeded with excellent site selectivity. The first attack occurs at position 1, due to electronic reason

Comparative Endoscopic Anatomic Description of the Mitral Valvular Complex: a Cadaveric Study

Background We compared the aortic, left atrial, and apical approaches to visualize the mitral valve with the goal to investigate the endoscopic anatomy and give exact step-by-step descriptions of these views. Materials and Methods The mitral valvular complex of human cadaveric fresh hearts was investigated from three approaches using 0, 30, and 70 degrees rigid endoscopic optics. In 30 cases after the removal of the hearts, the endoscopes were introduced directly into the aortic root through an aortotomy, left atrium through a standard atriotomy, and apex of the heart through a transmural incision. In 10 cases, the in situ visualization was performed using standard surgical approaches, such as partial upper ministernotomy, right and left minithoracotomy. The investigation was performed first with the mitral valve open, then the left ventricle was filled with saline, and the valve was closed by clamping the aorta. Results For the visualization of ventricular surfaces of the mitral leaflets and the subvalvular apparatus, the apical approach was most optimal. The aortic approach had limitations at the posterior leaflet. Using the atrial approach, we did not obtain any direct visual information about the subvalvular apparatus with the valve closed. The atrial surfaces of the leaflets were best visible using both the atrial and apical approaches with the mitral valve open. In the case of a closed valve, the apical approach did not allow for an investigation of the atrial surfaces. The aortic approach was useful to visualize the atrial surface of the posterior leaflet with an opened valve. Conclusion In mitral valve repairs through the left atrium, an additional aortic or apical view could be useful to obtain functional information about the subvalvular apparatus by the sealing probe

α-Azido Ketones, Part 8: Base-Induced Coupling of α-Azido Ketones with a 1,2-Diaza-1,3-diene as a Michael Acceptor1

Carbanions generated from various acyclic and cyclic α-azido ketones in the presence of bases were reacted with ethyl 3-[(carbamoylimino)amino]but-2-enoate as a Michael acceptor to give the corresponding adducts. The adducts of acyclic azides were unstable and eliminated hydrazoic acid to give the corresponding ethyl 2-[1-[(carbamoylamino)imino]ethyl]-4-oxo-4-phenylbut-2- enoates as (E,E/Z,E)-diastereomeric mixtures. The relative configuration of these diastereomers was determined by X-ray analysis. Adducts of cyclic α-azido ketones were obtained in diastereomerically pure form, with the exception of 2-azidobenzosuberone