Karaman, Rafik published the artcileSynthesis and characterization of the first water-soluble closely interspaced cofacial porphyrin dimer, Synthetic Route of 636-73-7, the publication is Journal of Organic Chemistry (1991), 56(11), 3470-2, database is CAplus.
The only documented example of a quadruply-bridged, closely-interspaced cofacial porphyrin dimer was synthesized by Kagan (1977). The target of this communication is the synthesis and characterization of the first water soluble quadruply-bridged, closely-interspaced cofacial porphyrin I (R = R1). Reaction of meso-tetrakis(3-bromomethylphenyl)porphyrin with m-pyridinesulfonamide provides the closely-interspaced cofacial porphyrin dimer I (R = R2) which on quaternization with MeI provides the water soluble I (R = R1). Reactions of I with Zn(OAc)2 provided the corresponding bis-zinc complexes I. Porphyrins I and their bis-zinc complexes, exist in a closed down conformation with closely approaching porphyrin planes or in an open conformation. It was established, on the basis of 1H-NMR UV/vis, and emission spectrophotometries, and I (R = R2) exists in a closed down conformation in DMSO or acetone and a more open conformation is CHCl3. With zinc complexes of I (or protonated I) the conformation is open regardless of the solvent.
Journal of Organic Chemistry published new progress about 636-73-7. 636-73-7 belongs to pyridine-derivatives, auxiliary class Pyridine,Sulfonic acid, name is Pyridine-3-sulfonic acid, and the molecular formula is C5H5NO3S, Synthetic Route of 636-73-7.
Referemce:
https://en.wikipedia.org/wiki/Pyridine,
Pyridine | C5H5N – PubChem