Inve stigation of substit uent effects phenyl on the intramolecular hydrogen bo nd of methyl ۳-oxo-۳-phenyl propanoa te (MOPP)

ß-diketones are capable of keto-enol tautomerism .the cis-enol forms of ß-diketones are stabilized by a str ong intramolecular hydrogen bond.The hydrogen bond formation leads to an enhancem ent of the re sonance co njugation of the ʌ –electrons ,which causes a m arked tendency equalization of the bond ord er of the valance bonds in the resulting six me mber chelate d ring. Therefore, it seems that any parameter that affects the electron density of the chelated rin g will change the hydrog en bond str ength. It is w ell known that substitution in Į or ȕ position drasti cally changes the hydrog en strength.

کلیدواژه ها:

elect ron-withdra wing group ، electron do nating group ، intramolecular hydro gen bond ، ß-diketones