2932: Heterocyclic compounds with oxygen hetero-atom(s) onl

293211: Tetrahydrofuran 293212: 2-furaldehyde (furfuraldehyde) 293213: Furfuryl alcohol and tetrahydrofurfuryl alcohol 293219: Heterocyclic compounds with unfused furan ring, nes 293221: Coumarin, methylcoumarins and ethylcoumarins 293229: Lactones, other than coumarins 293290: Heterocyclic compound,oxygen hetero-atom(s) only,nes 2932: Heterocyclic compounds with oxygen hetero-atom(s) onl