with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 2

Full Title

Heterocyclic compounds containing six-membered rings having one oxygen atom as the only hetero atom, condensed with other rings > ortho- or peri-condensed with carbocyclic rings or ring systems > Benzo[b]pyrans, not hydrogenated in the carbocyclic ring > other than with oxygen or sulphur atoms in position 2 or 4 > with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 2