Showing papers by "Georgia Melagraki published in 2005"

Prediction of high weight polymers glass transition temperature using RBF neural networks

Abstract: A novel approach to the prediction of the glass transition temperature (Tg) for high molecular polymers is presented. A new quantitative structure–property relationship (QSPR) model is obtained using Radial Basis Function (RBF) neural networks and a set of four-parameter descriptors, P MVðterÞðRterÞ, LF, DXSB and P PEI. The produced QSPR model (R 2 Z0.9269) proved to be considerably more accurate compared to a multiple linear regression model (R 2 Z0.8227). q 2004 Elsevier B.V. All rights reserved.

Novel Short-Step Synthesis of Functionalized γ-Phenyl-β-hydroxybutenoates and Their Cyclization to 4-Hydroxycoumarins via the N-Hydroxybenzotriazole Methodology.

Abstract: A novel method for the synthesis of functionalized 3- substituted 4-hydroxycoumarins is reported. C-Acylation com- pounds were derived from the reaction of the N-hydroxybenzotri- azole ester of the functionalized acetyl salicylic acids and a variety of active methylene compounds and cyclized to the title com- pounds. The synthesis is simple and the compounds are produced in yields varying from 39 to 80%. The structure of the newly prepared C-acylation compounds was thoroughly studied through NMR spectroscopy for the first time in the literature.