Fifteen-membered 8a-aza-8a-homoerythromycins derived from either erythromycin or clarithromycin have been acylated to form 4″-O-propenoyl derivative. These functionalized analogues underwent Michael reaction with primary or secondary amines to afford novel 8a-aza-8a-homoerythromycin—4″-(3-substituted-amino)propionates. This preparative sequence was adapted so that analogues could be made by parallel synthesis. Among them, 4-quinolone derivatives show particularly good antibacterial potency against macrolide resistant bacteria, comparable or better than azithromycin and telithromycin.