An improved process is provided for selectively synthesizing pyridine and 3-alkylpyridine in high yield by reacting ammonia and a carbonyl reactant selected from the group consisting of formaldehyde, an aldehyde containing from 2 to 4 carbon atoms, a ketone containing from 3 to 5 carbon atoms, and mixtures thereof under effective conditions in the presence of a catalyst comprising an active form of a synthetic porous crystalline MCM-49 or synthetic porous crystalline material characterized by an X-ray diffraction pattern including interplanar d-spacings at 12.36.+-.0.4, 11.03.+-.0.2, 8.83.+-.0.14, 6.18.+-.0.12, 6.00.+-.0.10, 4.06.+-.0.07, 3.91.+-.0.07, and 3.42.+-.0.06 Angstroms, e.g., MCM-22, and recovering from the resulting reaction mixture a product enriched in pyridine and 3-alkylpyridine.