In general, if the atoms that make up the ring contain heteroatoms, such rings become heterocycles, and organic compounds containing heterocycles are called heterocyclic compounds. An article called Synthesis of 4-amino-2-chloropyridine, published in 2005-09-30, which mentions a compound: 2402-95-1, Name is 2-Chloropyridine 1-oxide, Molecular C5H4ClNO, Formula: C5H4ClNO.
4-Amino-2-chloropyridine was synthesized from 2-chloropyridine by oxidation with hydrogen peroxide and nitration with fuming nitric acid to give 2-chloro-4-nitropyridine-N-oxide followed by reduction in 75% overall yield.
Compounds in my other articles are similar to this one(2-Chloropyridine 1-oxide)Formula: C5H4ClNO, you can compare them to see their pros and cons in some ways,such as convenient, effective and so on.
Reference:
Isoxazole – Wikipedia,
Isoxazole | C3H3NO – PubChem