¹⁵N NMR: Iminothiol‐thioamide tautomerism of 2‐mercaptobenzazoles and 1‐methyl‐2‐mercaptoimidazole

Abstract

lSN NMR spectra of a number of 2-mercaptoazoles were obtained and the position of the iminothiol-thioamide prototropic tautomeric equilibrium was determined. Because of the large chemical shift difference of cu 100 ppm between the iminothiol and thioamide nitrogen atoms, the I5N chemical shifts of the S-methyl and N-methyl analogs of each tautomer provided reasonable chemical shift models for the same nitrogen atom in the tantomers. Only a small correction for an N-methyl effect was required.

2-Mercaptobenzoxazole pentacyanoferrate(II/III) complexes: UV-Visible, Mössbauer, electron paramagnetic resonance, electrochemistry and molecular modeling

“…1, 2004 tautomer with the protonated N-atom. 7,8 Most of the electron density of the oxygen is in resonance with the aromatic ring making it a poor donor atom. Although S↔N linkage isomerism in bzoxs complexes is possible, no evidence has ever been published.…”

Spectroscopic Studies of Methimazole Reactivity toward the Aquapentacyanoferrate (II) Ion in Aqueous Solutions

“…The 1 H, 13 C, and 15 N NMR spectra, plus a 1 H-15 N (HMBC) spectrum, were recorded in DMSO-d 6 on a Bruker Avance 600 spectrometer operating at 600. [3,4] confirmed that the used MMI ligand was present in DMSO solely as thione tautomer.…”

Synthesis and Pain Inhibition Activity of the Analogs of 1-Allyl-3-Benzoylthiourea for New Analgesic Lead Compound Discovery

“…It also showed sharp strong absorbtion at 1664-1692 cm -1 corresponding to vinylic double bond, and a broad band at 3459-3466 cm -1 corresponding to the -OH iminol, the tautomeric forms of amide. 19 Mass spectra showed correct molecular ion peaks and fragmentation pattern. Isotopic patterns were utilized to confirm the presence of chloro substituent.…”