SEARCH Articles Figures Tables Five-membered heterocycles with O and N atoms Lactolides (s. a. O-Heterocyclics, 2-alkoxy N-halogenaminoalcohol N- and O-Heterocycles N- and O-Heterocyclic carboxylic acids O-Acylamino-N-heterocyclics O-Amino-N-heterocyclics O-Cyanamino-N-heterocyclics O-Halogeno-N-heterocyclic O-Hydroxy-N-heterocyclics O-heterocycles