[Hydrophobic constant values (delta RM0) of functional groups. I. Comparative study of delta RM0 values determined in...

delta RM0 values of functional groups (methyl, ethyl, n-propyl, methylene, phenyl, benzyl, saturation) of nitrogen bridgehead compounds [PP = pyrido(1,2-a)-pyrimidine, THPP = tetrahydropyrido(1,2-a)-pyrimidine, CTM-PP = 2,3-cyclotrimethylpyrido(1,2-a)-pyrimidine, CTM-THPP = 2,3-cyclotrimethylenetetrahydropyrido(1,2-a)-pyrimidine, CTRM-PP = 2,3-cyclotetramethylenepyrido(1,2-a)-pyrimidine, CTRM-THPP = 2,3-cyclotetramethylene-tetrahydropyrido(1,2-a)-pyrimidine, CTRM-THPP = 2,3-cyclotetramethylene-tetrahydropyrido(1,2-a)-pyrimidine, THPQ = tetrahydropyrroloquinazoline-, HHAQ = hexahydroazepinoquinazoline-derivates have been calculated from difference of retention values measured on RP-di-C1 stationary phase using methanol + water mobile phases of 6 (10 respectively) various compositions and of retention values (RM0) extrapolated to 0% organic phase. Retention data have been determined in normal chambers loaded with change of phase rate because of the vapour space of the developing chamber and in so-called pressurized ultramicro chamber which is free of change of phase rate and that of vapour space, respectively. It has been ascertained that delta RM0 values of same functional groups--that had been measured in the two different chamber systems--have not significantly differ from each other. It has also been established that opposite direction distortions of RM0 values--measured in normal chambers with mobile phases nearing or moving off 0% organic phase--have generally similar effects on delta RM0 values which are free of change of phase rate. Significant investigations were carried out by programs written on TEXAS SR-52 computer and work has always been done in 95% confidence interval.