Organic Compounds (class 532, Subclass 1)

Heterocyclic carbon compounds containing a hetero ring having chalcogen (i.e., oxygen, sulfur, selenium or tellurium) or nitrogen as the only ring hetero atoms (Class 540/1)

Cyclopentanohydrophenanthrene ring system containing (Class 540/2)
Azaporphyrins (Class 540/121)
Porphyrins (including hydrogenated; e.g., chlorophyll, etc.) (Class 540/145)
Hetero ring is four-membered containing nitrogen and having chalcogen double bonded directly to a ring carbon which is adjacent to the ring nitrogen (Class 540/200)
The hetero ring contains at least eight members including nitrogen and carbon (Class 540/450)
The hetero ring contains seven members including nitrogen and carbon (Class 540/484)

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