Proton and carbon-13 chemical shift data have been acquired for 2 6, 7, 8, 9-tetrahydro-4H- pyrido [1, 2-a] pyrimidin-4-ones and 20 methylated derivatives. Least-squares regression analysis has been undertaken on the aliphatic ring carbons of compounds with unequivocal conformations to determine the methyl substituent parameters for the four distinct aliphatic positions, and the results have been used to estimate the position of equilibrium of ...
![4H-Pyrido[1,2-a]pyrimidine-3-carboxylicacid, 4-oxo-, ethyl ester Structure](https://image.chemsrc.com/caspic/142/32092-18-5.png)
![6,7,8,9-Tetrahydro-4-oxo-4H-pyrido[1,2-a]pyrimidine-3-carboxylic acid ethyl ester Structure](https://image.chemsrc.com/caspic/251/38326-36-2.png)