Tricyclic derivatives of bispidine as AMPA receptor allosteric modulators

1. Download : Download high-res image (210KB)
2. Download : Download full-size image

     

Direct formylation of 2-pyridone core of 3-N-methylcytisine via Duff reaction; synthesis of 9-enyl, 9-ynyl and 9-imino derivatives

The first direct synthesis of 3-N-methyl-9-formylcytisine via electrophylic formylation is described. It is established, that Vilsmeier-Haack and Gatterman variants of this reaction are unsuccessful in the case with 3-substituted (-)-cytisine derivatives, but Duff procedure (with hexamethylenetetramine in trifluoroacetic acid) gives a possibility to obtain the target pseudo aromatic aldehyde with the 69% yield. Convenient precursors for [4 + 2]- or [3 + 2]-cycloaddition reactions are obtained by means of condensation of synthesized 3-N-methyl-9-formylcytisine with acetone, nitromethane and phosphorous ylides with yields from 70 to 87%. Alternative aprroach to alkenyl products and to 9-alkynyl-3-methylcytisine is realized using the Heck and Sonogashira cross-coupling reactions of methyl vinyl ketone, cyclohexenone or trimethylsilylacetylene with 9-bromo-3-methylcytisine (55, 70 and 60% accordingly). It is shown, that interaction of 3-N-methyl-9-formylcytisine with hydroxylamines leads to corresponding nitrone (93%) and oxime (70%). All individual compounds are isolated by column chromatography and completely characterized on the basis of NMR spectroscopy data.     

Phenyl α-bromovinyl sulfone in cycloadditions with azomethine ylides: an unexpected facile aromatization of the cycloadducts into pyrroles

Phenyl α-bromovinyl sulfone reacts with glycine ester Schiff bases regioselectively in the presence of catalytic amounts of AgOAc and DBU yielding polysubstituted pyrrolidine cycloadducts. Utilization of excess DBU induces subsequent facile aromatization of the cycloadducts and affords 5-arylpyrrole-2-carboxylic acid esters in 39-85% yields in a single step.     

A study of Galerkin method for the heat convection equations

The paper investigates the Galerkin method for an initial boundary value problem for heat convection equations. New error estimates for the approximate solutions and their derivatives in strong norm are obtained.     

Convergent and flexible approach to stereodefined polyhydroxylated fragments

Stereodefined acyclic polyhydroxylated fragments characteristic to polyketide natural products could be easily prepared in good yields and excellent diastereoisomeric ratios from common and simple enol carbamates. The reaction provides these fragments through a combined, one-pot sequence of metalation, carbamoyl transfer, aldol reaction, and finally Tishchenko reduction. This strategy assembles up to five consecutive stereogenic centers with exceptional stereocontrol. 2009 Elsevier Ltd. All rights reserved.     

More Causes Less Effect: Destructive Interference in Decision Making

We present a new experiment demonstrating destructive interference in customers’ estimates of conditional probabilities of product failure. We take the perspective of a manufacturer of consumer products and consider two situations of cause and effect. Whereas, individually, the effect of the causes is similar, it is observed that when combined, the two causes produce the opposite effect. Such negative interference of two or more product features may be exploited for better modeling of the cognitive processes taking place in customers’ minds. Doing so can enhance the likelihood that a manufacturer will be able to design a better product, or a feature within it. Quantum probability has been used to explain some commonly observed “non-classical” effects, such as the disjunction effect, question order effect, violation of the sure-thing principle, and the Machina and Ellsberg paradoxes. In this work, we present results from a survey on the impact of multiple observed symptoms on the drivability of a vehicle. The symptoms are assumed to be conditionally independent. We demonstrate that the response statistics cannot be directly explained using classical probability, but quantum formulation easily models it, as it allows for both positive and negative “interference” between events. Since quantum formalism also accounts for classical probability’s predictions, it serves as a richer paradigm for modeling decision making behavior in engineering design and behavioral economics.