ether organonitrogen compound oxime O-ether 41.998 CHEBI:36816 CNOR3 O-organyl oximes R2C=NOR' (R' =/= H). O-substituted oximes [*]O\N=C(/[*])[*] chebi_ontology oxime O-ether oxime O-ethers oxime O-ethers oxime ether oxime ethers