A combination of 1D and 2D NMR techniques, including HMQC, HSQC, ¹H-¹H COSY and HMBC, was used to provide completely assigned ¹H and ¹³C NMR data for the structures of three 3-[substituted methylidene]-1H,3H-naphtho[1,8-cd]-pyran-1-ones—3-[(4-methoxyphenyl)methylidene]-1H,3H-naphtho[1,8-cd]-pyran-1-one, 3-[(4-fluorophenyl)methylidene]-1H,3H-naphtho-[1,8-cd]-pyran-1-one and 3-[(thiophen-3-yl)methylidene]-1H,3H-naphtho[1,8-cd]-pyran-1-one. The heteronuclear coupling constants ^1–4J_CF and ^3–4J_HF were correspondingly determined. Additionally, IR and Raman spectral data were provided in support of the assigned structures.

The structure verification of 5′-oxospiro-(fluorene-9,4′-imidazolidine)-2′-thione by NMR is reported. Toward this aim, 2D NMR techniques including ¹H-¹H COSY, HMQC, and HMBC experiments were used to assist with the assignment of the ¹H and ¹³C chemical shifts for the corresponding structure. The mutual interpretation of the 1D and 2D NMR spectra ensured a complete and accurate ¹H and ¹³C NMR data assignment for 5′-oxospiro-(fluorene-9,4′-imidazolidine)-2′-thione.

The structure of spiro-(fluorene-9,4’-imidazolidine)-2’,5’-dithione was verified by 1D (¹H, ¹³C, DEPT 135) and 2D NMR (¹H-¹H COSY, HMQC and HMBC) spectroscopy. Additionally, the completely assigned NMR data was supported by Raman band assignments. HOSE predictions were incorporated by using the open-access NMRShiftDB database for verification of the assigned ¹³C NMR chemical shifts.

The structure verification of 5'-oxospiro-(fluorene-9,4'-imidazolidine)-2'-thione by NMR was reported. For the aim, 2D NMR techniques including 1H-1H COSY, HMQC and HMBC experiments were used to assist the assignment of the 1H and 13C chemical shifts for the corresponding structure. The mutual interpretation of the 1D and 2D NMR spectra ensured a complete and an accurate 1H and 13C NMR data assignment for 5'-oxospiro-(fluorene-9,4'-imidazolidine)-2'-thione.

A number of 1D and 2D NMR techniques, such as ¹H, ¹³C, DEPT 135, ¹H-¹H COSY, HSQC, and HMBC, were utilized for the structure verification of 4-(8-propyl-2,4-dithioxo-1,3-diazaspiro[4.5]decan-3-yl)spiro[1,5-dihydro-1,5-benzodiazepine-2,3′-indoline]-2′-one). The NMR spectra provided evidence for the tautomeric conversion of the compound. The completely assigned NMR data was supported additionally by ATR.