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 Chemical shifts in proton NMR spectra of 2-substituted furans and electrophilic constants σp+, published in 1980-07-31, which mentions a compound: 3194-15-8, mainly applied to furan NMR LFER; substituent constant NMR furan, SDS of cas: 3194-15-8.
Published values of substituent-induced chem. shift changes (Δδ) at H-5 of 2-substituted furans were correlated with σp+ constants by Δδ = 0.654 σp+ – 0.017. This equation was then used to find the σp+ constants of 15 substituents, including heterocyclic and oxime-containing groups.
In some applications, this compound(3194-15-8)SDS of cas: 3194-15-8 is unique.If you want to know more details about this compound, you can contact with the author or consult more relevant literature.
Reference:
Benzoxazole – Wikipedia,
Benzoxazole | C7H5NO – PubChem