A QSAR study of two sets of carbonic anhydrase inhibitors is presented using a variety of molecular descriptors including topological indices. The first set consists of 29 benzenesulphonamides, and the second set includes 35 sulphanilamide Schiff bases. Two regression methodologies have been used involving ridge regression and the CODESSA program, and their results are compared with those of previous QSAR studies. Good correlations were found for the former set, and less satisfactory results for the latter set when the number of molecular descriptors is kept below five.

An interesting observation was made when studying the S N Ar reaction between several 4-aryloxy-7-nitrobenzofurazans (2) and several amino acids leading to the apparition of detectable fluorescence from the substitution products 3. Acidic amino acids reacted very slowly=while basic amino acids react fastest with 2 having an unsubstituted phenyl or a 4-formyl-phenyl Ar group. Amongst neutral amino acids, proline reacts fastest at room temperature after 100 min. with 2 having a methoxy-substituted Ar group.

Colorectal cancer is a malignant tumor, one of the main types of cancer which produces a large number of deaths each year in many countries around the world. The main objective of this work is to employ various bioinformatics tools to perform docking of the transitional metal complexes (Zn (II), Co (II), Cu (II), Fe (II), Ni (II)) with cholic acid (AC) as ligand against Aurora A Kinase (RCSB Protein Data Bank code: 2X6E). Molegro Virtual Docker (MVD) was used for the docking process. The molecular docking score and the values of the statistic parameter Root Mean Square Deviation (RMSD) are presented in Table 1. The results obtained in this study serve to design new complex combinations with potential action against Aurora A Kinase inhibitor.

New possibilities for estimating octanol/water partition coefficients (logP) and the water solubility (S w ) were investigated using Kovàts retention indices (I) obtained from GLC retention data for 132 volatile organic compounds belonging to 7 different chemical classes (hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids, esters and halogen compounds). Application of the multilinear regression method led to six equations, all involving index I, as follows: (i) direct correlation logP vs. I (eq.1); (ii) logP vs. I , molar refractivity, and surface tension (eq. 2); (iii) logP vs. I and structural characteristics (eqs. 3, 4 and 6); (iv) logP vs. the I/S w ratio (eq. 5). Excepting eq. 1 (which showed relatively weak correlations), eqs. 2 -6 can provide reliable values for logP and for logS w as proved by the significant statistical parameters. The general models presented through eqs. 2 -6 may also be applied in estimation of other biological and/or ecological important properties, which are linearly dependent on the logP or log S w values. By generalization, a new calculation method is suggested (eq. 7), in order to allow the estimation of logP or logS w in terms of the number of bonds and the Kovàts retention index.

The sequence of all paths pi of lengths i = 1 to the maximum possible length in a hydrogen-depleted molecular graph (which sequence is also called the molecular path code) contains significant information on the molecular topology, and as such it is a reasonable choice to be selected as the basis of topological indices (TIs). Four new (or five partly new) TIs with progressively improved performance (judged by correctly reflecting branching, centricity, and cyclicity of graphs, ordering of alkanes, and low degeneracy) have been explored. (i) By summing the squares of all numbers in the sequence one obtains Sigmaipi(2), and by dividing this sum by one plus the cyclomatic number, a Quadratic TI is obtained: Q = Sigmaipi(2)/(mu+1). (ii) On summing the Square roots of all numbers in the sequence one obtains Sigmaipi(1/2), and by dividing this sum by one plus the cyclomatic number, the TI denoted by S is obtained: S = Sigmaipi(1/2)/(mu+1). (iii) On dividing terms in this sum by the corresponding topological distances, one obtains the Distance-reduced index D = Sigmai{pi(1/2)/[i(mu+1)]}. Two similar formulas define the next two indices, the first one with no square roots: (iv) distance-Attenuated index: A = Sigmai{pi/[i(mu + 1)]}; and (v) the last TI with two square roots: Path-count index: P = Sigmai{pi(1/2)/[i(1/2)(mu + 1)]}. These five TIs are compared for their degeneracy, ordering of alkanes, and performance in QSPR (for all alkanes with 3-12 carbon atoms and for all possible chemical cyclic or acyclic graphs with 4-6 carbon atoms) in correlations with six physical properties and one chemical property.