Synthesis of N-heteryl-beta-[(2-alkoxyethyl)oxy]/beta-[[2-(N,N- dialkylamino)ethyl]oxy]acetamides as possible H1-antihistaminics.

The synthesis of beta-[2-(alkoxyethyl)oxy]- and beta-[[2-(N,N-dialkylamino)ethyl]oxy]acetamides containing an N-heteryl moiety is reported. Three heteryl systems, 2-phenyl/methyl-3,4-dihydro-4-oxoquinazolin-3- yl, 5-aryl-1,3,4-oxadiazol-2-yl, and 5-alkyl-1,3,4-thiadiazol-2-yl, were employed. Appropriate heterylamines were first converted into their respective chloroacetamides and then reacted with 2-alkoxyethanols/2-(N,N-dialkylamino)ethanols in dry acetone in the presence of anhydrous potassium carbonate to obtain the title compounds. Ten such new acetamides from each series were synthesized and characterized. Their in vitro antihistaminic activity was determined using the isolated guinea pig ileum method. The IC50 values of the compounds indicated correlations with their structural and electronic features.