Search

The benzo[1,4]-oxazine ring system executing an important template has attracted considerable interest in the search for novel pharmaceutical compounds, but their pyridine derivatives were rarely mentioned in the literature. Only very few like synthesis of 2H-pyrido[3,2-b][1,4]oxazine, pyrido[4,3-b][1,4]oxazine and 4-acetyl-3(R)and 3(S)(hydroxymethyl)-3,4-dihydro-2H-pyrido[3,2-b]oxazine were reported. On the other hand most of the compounds reported in the literatures possess [1,4]-oxazinone moieties. Thus the reported methods demonstrated the synthesis of pyrido[3,2-b][1,4]-oxazine derivatives but there is no synthetic approach valuable for the synthesis of its isomer pyrido[2,3-b][1,4]-oxazine series having the nitrogen of pyridine and N of oxazine in trans fashion. It is known that 2-amino-3-pyridol is liable to O-alkylation rendering the formation of pyrido [3,2-b][1,4]oxazine. The selection of 2hydroxy pyridine is less liable and more problematic for the O-alkylation to obtain [1,4]-oxazine. We have earlier reported the reaction of 2-chloro-3-pyridol with chloroacetamides could undergo Smiles rearrangement to afford pyrido[2,3b][1,4]oxazinones. In this paper we outline the approach to synthesize pyrido[2,3-b][1,4]oxazine as potential scaffold for bioactive compounds. Endlessly, benzo[1,4]oxazines and pyrido[3,2-b][1,4]oxazines are prepared by direct cyclization of 2-haloacetyl halides or alkyl 2-halopropionates with 2-aminophenol or 2amino-3-hydroxypyridine. A similar approach, however, is not directly applicable to the pyrido[2,3-b][1,4]oxazine ring system. Nevertheless it was felt that the Smiles rearrangement could be exploited to circumvent this limitation. Since the Smiles rearrangement necessitates an electron-deficient center to proceed at a reasonable rate, we selected 2haloacetamide and 2-halo-3-hydroxypyridine as the reaction partners. The reduction of the lactam function with metal hydrides was found to be promising but it was found that sodium borohydride was better reagent for reduction of pyrido[2,3-b][1,4]oxazinone. In order to form the oxazine the hydroxy group was replaced with mesyl group by reacting with mesyl chloride and the mesyl ester thus obtained was removed with sodium methoxide to afford pyrido[2,3b][1,4]-oxazines. The use of three-step reaction condition in converting the oxazine by reduction of lactam, converting to O-Ms and the removal of O-Ms by base afforded pyridooxazines. Moreover the regioselective formation of pyrido[3,2-b][1,4]oxazine could be understood by this and it can be applied for the synthesis of large number of heterocycles by Diels-Alder or Aza Diels-Alder reactions to synthesize a various kinds of scaffold for new drug development. In an demonstrative experiment, reaction of 2-chloro-3hydroxy pyridine with (S)-2-chloro-N-(1-phenylethyl) acetamide 2 in the presence of potassium carbonate furnished (S)-2-(2-chloropyridin-3-yloxy)-N-(1-phenylethyl) acetamide 3 as the major product in 96% yield (Scheme 1). The 2-chloro-N-(1-phenylethyl) acetamide 2 was prepared by known procedures using chloroacetyl chloride with (S)(−)-α-methyl benzylamine 1 in the presence of potassium carbonate (95% yield). The subsequent exposure of 3 with cesium carbonate afforded cyclized product, (S)-1-(1

In the past 30 years as the pulse width of lasers has been narrowed and high-power lasers have been developed, researches on the interaction between photon and materials using femtosecond lasers have been actively conducted. The high energy density of femtosecond pulsed lasers enables nonlinear photoionization processes in several ways depending. This paper reports a study of a type Argentum direct laser writing in silver containing zinc phosphate glasses by inducing a nonlinear absorption deformation of femtosecond laser pulses. When silver-containing zinc phosphate glasses are irradiated with femtosecond laser pulses, ring-shaped clusters are formed due to non-linear absorption. The fluorescence properties and the refractive index of the silver cluster induced by this deformation are different from those of the original glass.Simultaneous comparisons of chemical micro probes, NSOM and numerical modeling were used to analyze the laser-induced silver species distribution. The results significantly strengthen the understanding of material modifications in such glasses in a non-thermal interaction regime. In particular, it has been found that the spatial distribution of species in silver-containing glasses produced by femtosecond laser irradiation has a significant effect on chemical etching selectivity.The Y-shaped beam splitters, 2D structures made by using type A DLW, was fabricated and its performance was measured. It was confirmed that a waveguide of a general shape in which the refractive index of the core is larger than that of cladding can be produced through type A DLW. Since the type A DLW always induces positive refractive index changes from 2.7x10-3 to 5.1x10-3, it is very suitable for making waveguide. A symmetric Y-junction and various asymmetric Y-junctions were designed and fabricated using double line waveguides, and the output ratios were measured according to the transition of the inject position. It was confirmed that the output ratio could be from 96%-4% to 57%-43% due to the different irradiance in the process of writing between the upper branch and lower branch. So DLW in silver containing zinc phosphate glasses can be utilized easily and quickly to fabricate the desired type of optical device with only the writing process.Finally, by researching 5D optical data storage (ODS) using type A DLW, the scope of application was further expanded. We have demonstrated 5D optical data storage encoded in orientated type A DLW modifications by using a relatively low laser irradiance compared to conventional DLW. Five dimensions were achieved by adding the orientation of ellipse pattern and fluorescence intensity to 3D position. The ellipse pattern was created by anamorphic focusing, and the orientation was adjusted to 16 levels by employing SLM. In addition, AOM device was used to adjust the femtosecond laser irradiance of 16 levels.To confirm the possibility of the proposed 5D ODS, two different images were simultaneously embedded in one image by type A DLW. And the two different original images of 4-bit bitmap format were successfully restored. The corresponding reading fidelities of 60.5% and 25.1% were obtained for the orientation direction and fluorescence intensity levels, respectively. In addition, it is shown that the reading accuracy can be greatly improved to 85.0% and 47.1% when 3-bit bitmap format was applied. Using the proposed this technology, we have reached a maximum data density of 14.9 Gb/cm3, and we believe that data storage densities of up to 119.2 Gb/cm3 (using NA = 1.3 oil target) can be achieved.In conclusion, the fluorescence characteristics of type A DLW in silver containing zinc phosphate glasses were studied, and its utility as a multi-dimension application was confirmed. We believe this technology has great potential for nano-scale patterning in semiconductor and fabrication of micro-scale optical devices.; Au cours des 30 dernières années, alors que la largeur d'impulsion des lasers a été réduite et que les lasers haute puissance ont été développés, des recherches sur l'interaction entre le photon et les matériaux utilisant des lasers femtosecondes ont été activement menées. La haute densité d'énergie des lasers pulsés femtosecondes permet des processus de photoionisation non linéaire de plusieurs manières selon. Cet article rapporte une étude d'une écriture laser directe de type Argentum dans des verres de phosphate de zinc contenant de l'argent en induisant une déformation d'absorption non linéaire d'impulsions laser femtoseconde. Lorsque des verres de phosphate de zinc contenant de l'argent sont irradiés avec des impulsions laser femtoseconde, des amas en forme d'anneau se forment en raison d'une absorption non linéaire. Les propriétés de fluorescence et l'indice de réfraction de l'amas d'argent induit par cette déformation sont différents de ceux du verre d'origine.Des comparaisons simultanées de microsondes chimiques, de NSOM et de modélisation numérique ont été utilisées pour analyser la distribution des espèces d'argent induite par laser. Les résultats renforcent considérablement la compréhension des modifications matérielles de ces verres dans un régime d'interaction non thermique. En particulier, il a été constaté que la distribution spatiale des espèces dans des verres contenant de l'argent produits par irradiation laser femtoseconde a un effet significatif sur la sélectivité de la gravure chimique.Les séparateurs de faisceau en forme de Y, des structures 2D fabriquées à l'aide de DLW de type A, ont été fabriqués et leurs performances ont été mesurées. Il a été confirmé qu'un guide d'onde de forme générale dans laquelle l'indice de réfraction du noyau est plus grand que celui du revêtement peut être produit par le biais d'un DLW de type A. Étant donné que le DLW de type A induit toujours des changements d'indice de réfraction positifs de 2,7 x 10-3 à 5,1 x 10-3, il est très approprié pour fabriquer un guide d'onde. Une jonction Y symétrique et diverses jonctions Y asymétriques ont été conçues et fabriquées à l'aide de guides d'ondes à double ligne, et les rapports de sortie ont été mesurés en fonction de la transition de la position d'injection. Il a été confirmé que le ratio de sortie pourrait être de 96% -4% à 57% -43% en raison de l'irradiance différente dans le processus d'écriture entre la branche supérieure et la branche inférieure. Ainsi, les verres DLW en argent contenant du phosphate de zinc peuvent être utilisés facilement et rapidement pour fabriquer le type de dispositif optique souhaité avec uniquement le processus d'écriture.Enfin, en recherchant le stockage optique de données 5D (ODS) à l'aide de DLW de type A, le champ d'application a été élargi. Nous avons démontré le stockage optique de données 5D encodé dans des modifications orientées DLW de type A en utilisant un rayonnement laser relativement faible par rapport au DLW conventionnel. Cinq dimensions ont été obtenues en ajoutant l'orientation du motif d'ellipse et l'intensité de fluorescence à la position 3D. Le motif d'ellipse a été créé par mise au point anamorphique, et l'orientation a été ajustée à 16 niveaux en utilisant SLM. De plus, un dispositif AOM a été utilisé pour régler l'irradiance laser femtoseconde de 16 niveaux.Pour confirmer la possibilité du 5D ODS proposé, deux images différentes ont été simultanément intégrées dans une image par DLW de type A. Et les deux images originales différentes au format bitmap 4 bits ont été restaurées avec succès. Les fidélité de lecture correspondantes de 60,5% et 25,1% ont été obtenues pour la direction d'orientation et les niveaux d'intensité de fluorescence, respectivement. De plus, il est démontré que la précision de lecture peut être considérablement améliorée à 85,0% et 47,1% lorsque le format bitmap 3 bits a été appliqué. [...]