The Chemistry of Carbonyl Cyanide. Dienophilic Properties of Carbonyl Cyanide and Diethyl Mesoxalate. Formation of Dihydropyran Derivatives

The reactions of carbonyl cyanide with butadiene or 2,3-dimethylbutadiene have been studoied. In either case there was found to take place diene condensation leading to corresponding derivatives of dihydropyran. Dihydropyran derivatives synthesis was also found to occur when die thylmesoxalate was condensed with the dienes. The correctness of the structure of the adducts obtained was established by degradation experiments

Combating state explosion in the detection of dynamic properties of distributed computations

In the context of asynchronous distributed systems, many important applications depend on the ability to check that all observations of the execution of a distributed program, or distributed computation, satisfy a desired (or undesired) temporal evolution of states, or dynamic property. Examples include the implementation of distributed algorithms, automated testing via oracles, debugging, and building fault-tolerant applications through exception detection and handling. When a distributed program exhibits a high degree of concurrency, the number of possible observations of an execution can grow exponentially, quickly leading to an explosion in the amount of space and time required to check a dynamic property. In the worst case, detection of such properties may be defeated. This is the run-time counterpart of the well-known state explosion problem studied in model checking. In this thesis, we study the problem of state explosion as it arises in the detection of dynamic properties. In particular, we consider the potential of applying well-known techniques for dealing with state explosion from model checking to the case of dynamic property detection. Significant semantic similarities between the two problems means that there is great potential for deriving techniques for dealing with state explosion in dynamic property detection based on existing model checking techniques. However, differences between the contexts in which model checking and dynamic property detection take place mean that not all approaches to dealing with state explosion in model checking may carryover to the run-time case. We investigate these similarities and differences and provide the development and analysis of two approaches for combating state explosion in dynamic property detection based on model checking methods: on-the-fly automata theoretic model checking, and partial order reduction.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The expedition of Francisco de Orellana and the exploration of the Amazon River as far as its mouth at the Atlantic : about the value of the source report of Gaspar de Carvajal

In this article, we undertake some problems which are practically absent in Polish studies. It is the expedition led by Francisco de Orellana, who, after eight months of risky navigation and having overcome innumerable obstacles, managed to reach the Atlantic, crossing a completely unknown river. The article focalise on plausibility of the main source that regards to the study of the exploration of Orellana, that is, the story of the eyewitness, the Dominican Gaspar de Carvajal. The verification of this source is based on a detailed study of the geographic points of reference that we find in this narration, showing that Carvajal’s manuscript can be considered a trustworthy source of information. Some additional studies complete the true profile of that episode of the history of the New World.Nuestra aportación aborda una problemática prácticamente ausente en la bibliografía polaca. Se trata de la expedición dirigida por Francisco de Orellana, quien, tras ocho meses de una arriesgada navegación y superación de innumerables obstáculos, logró llegar, recorriendo un río completamente desconocido, al Atlántico. Nuestra publicación se dedica por completo al problema de la verosimilitud de la principal fuente correspondiente al estudio de la exploración de Orellana, es decir el relato del testigo ocular, el dominico Gaspar de Carvajal. La verificación de esta fuente la basamos en un concienzudo estudio de los puntos geográficos de referencia que encontramos en esta narración, mostrando que el manuscrito de Carvajal se puede considerar como una fuente digna de confianza. Lectura de algunos estudios adicionales completa el verdadero perfil de aquel episodio de la historia del Nuevo Mundo

La probable composición del inventario ganadero de la expedición de Gonzalo Pizarro al País de la Canela (Una contribución a la crítica de las fuentes históricas)

Dentro de nuestros estudios en torno de la temprana exploración de la región amazónica (expedición de Gonzalo Pizarro y Francisco Orellana) han aparecido informaciones, en diferentes fuentes del siglo XVI, sobre grandes números de animales (caballos, perros, llamas y cerdos) que acompañaron al equipo de Pizarro en su salida de Quito (1540/1541). La magnitud de rebaños nos llamó tanta atención que nos propusimos verificar la veracidad de estas informaciones, recurriendo tanto a las fuentes históricas como, por cierto muy escasas, aportaciones contemporáneas. Como resultado salieron hartas dudas en cuanto a las informaciones mencionadas, particularmente a raíz de tratar de dilucidar la cuestión de la introducción de los animales europeos, con el propósito de su crianza, en el Nuevo Mundo

Synthesis of cyclopropyl-substituted furans by Brønsted acid promoted cascade reactions

Chloroacetic acid promotes an efficient and diastereoselective intramolecular cascade reaction of electron-deficient ynenones to deliver products featuring a 2,3,5-trisubstituted furan bearing a fused cyclopropyl substituent at the 5-position. Synthetically relevant polycyclic building blocks featuring rings of various sizes and heteroatoms have been synthesized in high yield using this mild acid-catalyzed reaction

Application of dehydroabietic acid in palladium-catalysed enyne cycloisomerisation

YesDehydroabietic acid (DAA) promotes palladium(0)‐catalysed cyclisations of arene‐tethered 1,7‐enynols and 1,m‐enynoates (m=6,7) to give fused carbocyclic dienes. 6,6,6,5‐Tetracyclic lactones are accessible by one‐pot cycloisomerisation/Diels–Alder reaction/lactonisation from 1,7‐enynols. Furthermore, asymmetric counteranion‐directed catalysis has been developed, which afforded an indene derivative with an all‐carbon quaternary stereogenic center.NSFC. Grant Number: 21462004 State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources. Grant Number: CMEMR2014A04 2015 GXNSFBA. Grant Number: 139032 GXN