Abstract: N-formyl compounds are useful fine chemicals and intermediates for medicines, pesticide, and herbicide. They are good solvents. We have obtained NMR spectra of a series of N-formyl compounds, general features of which are compared and discussed. Especially noticed the appearance of isomers due to double bond character of C-N bond and stabilization of hydrogen bond to the isomer. The spectra of the more complex N-formyl compounds are discussed in terms of the conclusions drawn from the spectra of simple compounds. To study the isomerism of N-formyl compounds, we have taken the temperature variation NMR technique. We have studied the ratio of isomers at different temperatures.It is our conclusion that the isomerism of N-formyl compounds is caused by double bond characer of C-N bond and hydrogen bond.

Key words: N-formyl compounds, NMR, Isomer, Hydrogen bond, Variation temperature experiment