THE SYNTHESIS AND CHEMISTRY OF SELECTED 4-METHYL-2-PYRROLIDONES AND 3-METHYL-PYRROLIDINES THE KARPLUS-EQUATION CONSTANT CALCULATION AND CARBON-13, NITROGEN-15 STUDY OF SELECTED PYRROLIDONES AND PYRROLIDINES

The purpose of this investigation was the synthesis and study of the configuration of various 4-methyl-2-pyrrolidones and 3-methyl pyrrolidines. Then, by using the steric energies and coupling constants to figure out the Karplus-equation constant of 5-member ring heterocyclic compounds. Initially, attempts were made to prepare a number of methyl-4-alkylamino-3-methyl-2-butenoates, stable as the hydrochloride, by the reaction of methyl-4-bromo-3-methyl-2-butenoate with a series of amines. The unsaturated amino ester was readily reduced to the corresponding methyl-4-alkylamino-3-methyl-butyrate hydrochloride. Methyl-4-t-butylamino-3-methyl-butyrate was hydrolyzed to 4-t-butylamino-3-methyl-butyric acid. When the hydrolyzation procedure was applied to methyl-4-cyclohexyl-3-methyl-butyrate, the desirable amino-acid, along with 2-pyrrolidone, was collected in a 1:2 ratio. When methyl-4-benzylamino-3-methylbutyrate was hydrolyzed, the only product was 1-benzyl-4-methyl-pyrrolidone. 1-Alkyl-4-methyl-2-pyrrolidones were obtained by vacuum distillation of the corresponding methyl-4-alkylamino-3-methylbutyrates which were initially refluxed under different conditions. The 3-methyl pyrrolidines were obtained by reducing the corresponding pyrrolidones in the presence of lithium aluminium hydride. The coupling constants were checked by a computer simulation program named NMR-SIM2 . The steric energies were done by a computer program-QCPE No 395. An equation dealing with the relationship among the dihedral angle, coupling constant, steric energy and Karplus constant was derived. By setting B = 0 and C = 1.4, the Karplus constant parameter A was figured out by putting each data set into that equation. A is equal 8.9 in this study. The (\u2713)C and (\u2715)N chemical shifts of pyrrolidones and pyrrolidines were determined. The coupling constants were calculated by using the available data and equations