Monoheterocyclic parent hydrides

Structure	Retained name	Hantzsch-Widman name	ChEBI
Mancude rings
	furan	oxole	CHEBI:35559
	thiophene	thiole	CHEBI:30856
	selenophene	selenole	CHEBI:30857
	tellurophene	tellurole	CHEBI:30858
	2H-pyran	2H-oxine *	CHEBI:35592
	4H-pyran	4H-oxine *	CHEBI:35593
	1H-pyrrole	1H-azole	CHEBI:19203
	2H-pyrrole	2H-azole	CHEBI:35558
	3H-pyrrole	3H-azole	CHEBI:35557
	1H-pyrazole	1H-1,2-diazole	CHEBI:17241
	3H-pyrazole	3H-1,2-diazole	CHEBI:38595
	4H-pyrazole	4H-1,2-diazole	CHEBI:38599
	1H-imidazole	1H-1,3-diazole	CHEBI:16069
	4H-imidazole	4H-1,3-diazole	CHEBI:51802
	pyridine	azine †	CHEBI:16227
	pyridazine	1,2-diazine	CHEBI:30954
	pyrimidine	1,3-diazine	CHEBI:16898
	pyrazine	1,4-diazine	CHEBI:30953
Saturated rings
	pyrrolidine	azolidine	CHEBI:33135
	pyrazolidine	1,2-diazolidine	CHEBI:33138
	imidazolidine	1,3-diazolidine	CHEBI:33137
	piperidine	azinane	CHEBI:18049
	piperazine	1,4-diazinane	CHEBI:28568
	morpholine	1,4-oxazinane	CHEBI:34856
	thiomorpholine	1,4-thiazinane	CHEBI:36392

*	The H-W name ‘oxine’ is not recommended by IUPAC “because it is used as a trivial name for 8-quinolinol” [1, p. 413].
†	The H-W name ‘azine’ is not recommended by IUPAC “because of its long established use as a class name for =N–N= compounds” [1, p. 413].

Reference

1. Powell, W.H. (1983) Revision of the extended Hantzsch-Widman system of nomenclature for heteromonocycles. Pure and Applied Chemistry 55, 409—416.