https://doi.org/10.1351/goldbook.P04764
Hexahydroporphyrins in which the nitrogen atoms and four @M03838@ positions are saturated.
Sources:
PAC, 1987, 59, 779. (Nomenclature of tetrapyrroles (Recommendations 1986)) on page 798 [Terms] [Paper]
White Book, 2nd ed., p. 294 [Terms] [Book]