Epoxide
Oxetane
Alpha-lactone
Beta-lactone
Gamma-lactone
Aziridine
Azetidine
Alpha-lactam
Beta-lactam
Gamma-lactam
Furan
Tetrahydrofuran
Pyrrole
Pyrrolidine
Thiophene
Tetrahydrothiophene
Imidazole
Pyrazole
Oxazole
Isoxazole
Thiazole
Triazole
Tetrazole
Pyridine
Piperidine
Piperazine
Morpholine
Indole
Benzoxazole
Benzthiazole
Quinoline
Isoquinoline
