In organic chemistry, atoms other than carbon and hydrogen are generally referred to as heteroatoms. The most common heteroatoms are nitrogen, oxygen and sulfur. Now I present to you an article called Conjugated Macrocycles Related to the Porphyrins. 25.Proton NMR Spectroscopic Evidence for a Preferred [18]Annulene Substructure in Carbaporphyrins from the Magnitude of Selected 4JH,H CH:C-CH3 Coupling Constants, published in 2003-03-07, which mentions a compound: 616-43-3, mainly applied to benzocarbaporphyrin preparation NMR, Recommanded Product: 3-Methyl-1H-pyrrole.
Two new benzocarbaporphyrins with four or five alkyl substituents have been synthesized by the “”3 + 1″” MacDonald methodol. At lower temperatures, the proton NMR spectrum of the asym. substituted carbaporphyrin I gave two NH resonances, while carbaporphyrin II, which retains a plane of symmetry, gave only one resonance of this kind. As no addnl. peaks were seen for the remaining protons, these data strongly support the proposal that a single tautomer predominates in solution where the two NH protons flank the interior CH. Carbaporphyrin I, which has a CH:CMe unit on the pyrrolic ring opposite the indene moiety, gave a long-range coupling constant of 4JMe,H = 1.3-1.4 Hz. On the other hand, the CH:CMe units of II, which correspond to the pyrrole rings on each side of the carbocyclic moiety, gave 4JMe,H = 0.9-1.0 Hz. These values are in accord with those expected if the exterior carbon-carbon bonds of the pyrrole units next to the indene ring are part of a fully delocalized 18π electron system, while the C:C bond of the remaining pyrrole ring retains substantial olefinic character.
This literature about this compound(616-43-3)Recommanded Product: 3-Methyl-1H-pyrrolehas given us a lot of inspiration, and I hope that the research on this compound(3-Methyl-1H-pyrrole) can be further advanced. Maybe we can get more compounds in a similar way.
Reference:
Synthesis and Crystal Structure of a Chiral C3-Symmetric Oxygen Tripodal Ligand and Its Applications to Asymmetric Catalysis,
Chiral lanthanide(III) complexes of sulphur–nitrogen–oxygen ligand derived from aminothiourea and sodium D-camphor-β-sulfonate