Assignment of the 13C-NMR spectrum of phenanthro[4,3-A]dibenzothiophene through the utilization of two-dimensional relayed coherence transfer and double quantum coherence spectroscopy

Total assignment of the ¹³C-nmr spectrum of the helical molecule phenanthro[4,3-a]dibenzothiophene at 125.762 MHz is reported. Assignments were made by the combined application of ¹³C-¹³C autocorrelated double quantum coherence and heteronuclear relayed coherence transfer (RELAY) experiments.     

Assignment of the 1H- and 13C-NMR spectra of phenanthro[1,2-b]thiophene through the concerted application of two-dimensional NMR spectroscopic techniques

Two-dimensional nmr spectroscopy, by virtue of its second frequency domain which permits the segregation of spectral information along two frequency axes, considerably simplifies many assignment problems and facilitates others which may be impossible using conventional nmr methodology. A compound which falls into the latter category of assignment problem is phenanthro[1,2-b]thiophene. The assignment of the ¹H- and ¹³C-nmr spectra of phenanthro[1,2-b]thiophene are, however, reported through the concerted application of two-dimensional nmr techniques. Experiments utilized in making the assignments included: auto-correlated homonuclear (COSY) two-dimensional spectroscopy; heteronuclear two-dimensional J-resolved spectroscopy; proton-carbon chemical shift correlation two-dimensional spectroscopy; and two-dimensional ¹³C-¹³C double quantum coherence spectroscopy.     

Assignment of the 1H- and 13C-NMR spectra of congested helicenes using two-dimensional NMR methods: Phenanthro[3′,4′:3,4]phenanthro[2,1-b]thiophene

Phenanthro[3′,4′:3,4]phenanthro[2,1-b]thiophene has been prepared and its highly congested proton and carbon nmr spectra assigned. The nmr assignments required concerted utilization of two-dimensional nmr techniques which included: COSY, direct and long range optimized heteronuclear chemical shift correlation and heteronuclear relayed coherence transfer.     

Complete assignment of the 1h- and 13c-nmr spectra of [1]benzothieno[2,3-c]naphtho[1,2-h]quinoline and [1]benzothieno[2,3-c]naphtho[1,2-h][1,2,4]triazolo[4,3-a]quinoline. Concerted use of two-dimensional nmr techniques

The ¹H- and ¹³C-nmr spectra of [1]benzothieno[2,3-c]naphtho[1,2-h]quinoline and [1]benzothieno[2,3-c]-naphtho[1,2-h][1,2,4]triazolo[4,3-a]quinoline were totally assigned using a combination of two-dimensional nmr techniques. After correlation of the proton signals by a COSY spectrum and one-bond heteronuclear correlation, complete assignment of the ¹H- and ¹³C-nmr spectra of the novel heterocyclic compounds required the application of long-range CH coupling information particularly for quarternary resonance assignments and the orientations of individual spin systems relative to one another.     

Natural abundance 13C - 13C coupling constants observed via double quantum coherence. Structural elucidation by the one- and the two-dimensional NMR experiements of velloziolone,a new seco-diterpene.

With the help of Natural Abundance ¹³C - ¹³C Coupling Constants, observed via double quantum coherence, the structural determination of VELLOZIOLONE (1), a new diterpene, has been carried out.