Solid-Liquid Equilibrium and Thermodynamic Properties of 6-Bromo-2-chloro-8-cyclopentyl-5-methylpyrido[2,3]pyrimidin-7(8 H)-one in 10 Pure Solvents and 3 Different Miscible Systems at T = (278.15-323.15) K

6-Bromo-2-chloro-8-cyclopentyl-5-methylpyrido[2,3]pyrimidin-7(8H)-one is a key intermediate in the synthesis of Ibrance. We used high-performance liquid chromatography to analyze the solubility of 6-bromo-2-chloro-8-cyclopentyl-5-methylpyrido[2,3]pyrimidin-7(8H)-one in 10 single solvents [dichloromethane, n-hexane, ethyl acetate, n-butyl alcohol, tetrahydrofuran (THF), ethyl alcohol, isopropanol, 1-propanol, dimethylformamide, and isophorone] and 3 binary solvents (ethyl acetate + ethyl alcohol, isophorone + isopropanol, and THF + ethyl alcohol) at atmospheric pressure from 278.15 to 323.15 K. The results show that temperature and the solubility of 6-bromo-2-chloro-8-cyclopentyl-5-methylpyrido[2,3]pyrimidin-7(8H)-one in single solvents and binary solvents are positively correlated. The solubility in pure solvents is fitted by the modified Apelblat model and the Buchwski-Ksiazaczak λh model, and the solubility data in the binary solvent are correlated by the CNIBS/R-K model and the Jouyban-Acree model. The good agreement between the calculated value of the equation and the experimental result is shown by the results of equation fitting. By comparing the average value of relative average deviation and root-mean-square deviation of the equations, we can see that the modified Apelblat model has the best correlation effect in the single solution systems and the CNIBS/R-K model has the best correlation effect in the miscible systems. The KAT-LSER model is used to explain the competition between solute-solvent interactions and solvent-solvent interactions in pure solvents.