SMILES: C[C@@]12CC(=O)O[C@@]13[C@@](C4=C(C(=C(N4)CC5=C(C(=C(N5)/C=C\\6/[C@H]([C@](/C(=C/C(=N3)[C@H]2CCC(=O)O)/N6)(C)CC(=O)O)CCC(=O)O)CC(=O)O)CCC(=O)O)CCC(=O)O)CC(=O)O)(C)O
Description: The molecule is the intermediate in the biosynthesis of vitamin B12 from uroporphyrinogen III in which three methyl groups have been introduced at positions 2, 7 and 20 of the tetrapyrrole framework and in which the carboxymethyl group at position 2 has been oxidised to form a lactone ring. It is a conjugate acid of a precorrin-3B(7-) and a precorrin-3B(6-).