Complete 1H and 13C NMR assignments of the epimeric menthane-1-carboxylic acids

Complete NMR analyses with full assignments for (1)H and (13)C NMR spectral data for both epimers of menthane-1-carboxylic acid are described. The NMR properties of the recently synthesized axial isomer had not been previously described, and through use of a variety of 1D and 2D techniques, additional information is provided for the equatorial isomer. As well as assignments of chemical shifts, homonuclear coupling constants were determined for the equatorial isomer and most of coupling constants were measured for the axial isomer.     

Complete 1H and 13C NMR assignments of clerodane diterpenoids of Salvia splendens

Unambiguous and complete assignments of 1H and 13C NMR chemical shifts for five clerodane diterpenes, four of them isolated from Salvia splendens (salviarin, splendidin and splenolides A and B) and one obtained by acetylation of splenolide A, are presented. The assignments are based on 2D shift-correlated [1H,1H-COSY, 1H,13C-gHSQC-1J(C,H) and 1H,13C-gHMBC-nJ(C,H) (n=2 and 3)] and nuclear Overhauser effect (NOE) experiments. The conformation of the rings of these compounds is supported by the 3J(H,H) values and NOE results.     

Complete assignments of (1)H and (13)C NMR spectroscopic data for two new triterpenoid saponins from Ilex pernyi

Ilexpernoside A and ilexpernoside B, two new pentacyclic C(4)-nortriterpenoid saponins, were isolated from the leaves of Ilex pernyi Franch. Their chemical structures were determined by MS, NMR spectroscopy and chemical analysis. Complete assignments of the (1)H and (13)C NMR spectroscopic data were achieved by 1D and 2D NMR experiments (HSQC, HMBC, (1)H-(1)H COSY and NOESY).     

Complete assignments of 1H and 13C NMR spectroscopic data for two new triterpenoid saponins from Ilex hainanensis

Two novel unsaturated E-ring pentacyclic triterpenoid saponins, ilexhainanoside A and ilexhainanoside B, were isolated from the leaves of Ilex hainanensis. Their chemical structures were determined by MS, NMR spectroscopy and chemical analysis. Complete assignments of the 1H and 13C NMR spectroscopic data were achieved by 1D and 2D NMR experiments (HSQC, HMBC, ROESY and 1H-1H COSY).     

Complete 13C NMR assignments for ent-kaurane diterpenoids from Sideritis species

In this work, the detailed NMR studies and full (13)C NMR assignments for five diterpenoids isolated from Sideritis caesarea and Sideritis athoa are described. The assignments are based on a combination of 1D and 2D NMR techniques including (1)H, (13)C, (1)H-(1)H COSY, gHSQC [(1)J(C,H)] and gHMBCδ(C) [(n)J(C,H)(n=2 and 3)] and NOESY experiments.     

1H and 13C NMR spectral assignments of some natural abietane diterpenoids

An NMR study of 11 naturally occurring abietane diterpenoids is described. In addition to one‐dimensional NMR methods, including DPFGSE 1D‐NOE spectra, two‐dimensional shift‐correlated experiments [¹H,¹H COSY, ¹H,¹³C‐gHSQC ¹J(C,H) and ¹H,¹³C‐gHMBC ⁿJ(C,H) (n = 2 and 3)] were used for the complete and unambiguous ¹H and ¹³C chemical shift assignments of these substances. Copyright © 2003 John Wiley & Sons, Ltd.     

1H and 13C NMR assignments for two new angular furanocoumarin glycosides from Peucedanum praeruptorum

Two novel angular-type furanocoumarin glycosides, peucedanoside A (1) and peucedanoside B (2), along with a known compound apterin (3), were isolated from the roots of Peucedanum praeruptorum Dunn. Their chemical structures were determined by MS, NMR spectroscopy and chemical analysis. Complete assignments of the 1H and 13C NMR spectroscopic data were achieved by 1D and 2D NMR experiments including DEPT, HSQC, HMBC and ROESY.     

Complete 1H and 13C NMR assignments for two new monodesmoside saponins from Pentaclethra macroloba (Willd.) Kuntze

A detailed NMR study and full assignments of the 1H and 13C spectral data for two novel triterpenoid saponins isolated from the stem bark of Pentaclethra macroloba (Willd.) Kuntze are described. Their structures were established using a combination of 1D and 2D NMR techniques including 1H,1H-COSY, TOCSY, NOESY, gs-HMQC and gs-HMBC, and also electrospray ionization mass spectrometry and chemical methods. The structures were established as 3beta-O-([O-beta-D-glucopyranosyl-(1-->2)-O-beta-D-glucopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->3)-O-alpha-L-rhamnopyranosyl-(1-->2)]-[O-beta-D-glucopyranosyl-(1-->3)-O-beta-D-glucopyranosyl-(1-->4)])-alpha-L-arabinopyranosylhederagenin (1) and 3beta-O-)[O-beta-D-glucopyranosyl-(1-->2)-O-beta-D-glucopyranosyl-(1-->4)-O-beta-D-glucopyranosyl-(1-->3)-O-alpha-L-rhamnopyranosyl-(1-->2)]-[O-beta-D-glucopyranosyl-(1-->3)-O-beta-D-glucopyranosyl-(1-->4)])-alpha-L-arabinopyranosyloleanolic acid (2).     

Complete assignments of 1H and 13C NMR spectral data for a novel diterpenoid from Semiaquilegia adoxoides

Semiaquilegoside A (1), a new diterpenoid, was isolated from the roots of Semiaquilegia adoxoides. Its chemical structure was established as 3beta, 11- dihydroxy-12-O-beta-D-glucopyranosyl-8,11,13-abietatrien-6-one through spectroscopic techniques and chemical analysis.     

Complete assignments of 1H and 13C NMR spectral data for three sesquiterpenoids from Inula helenium

The complete assignments of all the (1)H and (13)C NMR signals of three sesquiterpene lactones, 4-oxo-5(6),11-eudesmadiene-8,12-olide (1), 4-oxo-11-eudesmaene-8,12-olide (2) and (1(10)E)-5beta-Hydroxygermacra-1(10),4(15),11-trien-8, 12-olide (3), were carried out by various 2D NMR experiments. Compounds 1-3 were isolated from the roots of Inula helenium for the first time. Among them, 1 was identified as a new nor-sesquiterpene lactone, and 2 was isolated from a natural source for the first time. The (13)C-NMR data of compound 3 was also reported for the first time.     

Complete assignments of 1H and 13C NMR data for two new sesquiterpenes from Cyperus rotundus L.

Two new sesquiterpenes, epi‐guaidiol A (1) and sugebiol (3), together with four known sesquiterpenes, guaidiol A(2), sugetriol triacetate (4), cyperenoic acid (5), and cyperotundone (6) were isolated from the rhizomes of Cyperus rotundus L. Their structures were identified by MS and NMR experiments, and the complete assignments of ¹H and ¹³C NMR data for two new sesquiterpenes were obtained by the aid of two‐dimensional (2D) NMR techniques, including HSQC, HMBC, ¹H‐¹HCOSY and nuclear overhauser enhancement spectroscopy(NOESY). Copyright © 2009 John Wiley & Sons, Ltd.     

Complete 1H and 13C NMR assignments of four new oligosaccharides and two new glycosides from Periploca forrestii

Four new oligosaccharides (1–4), one new pregnane glycoside (5), and one new cardiac glycoside (6) were isolated from the roots of Periploca forrestii Schltr. (Asclepiadaceae), a traditional Chinese medicine used for the treatment of rheumatoid arthritis and wounds. Their structures were characterized on the basis of extensive analysis of NMR (¹H, ¹³C NMR, ¹H‐¹H COSY, HSQC, HMBC, TOCSY and ROESY) spectra. Copyright © 2009 John Wiley & Sons, Ltd.     

Complete 1H and 13C NMR assignments of three labdane diterpenoids isolated from Leonotis ocymifolia and six other related compounds

Unambiguous and complete assignments of ¹H and ¹³C NMR chemical shifts for three structurally complex labadane diterpenoids isolated from Leonotis ocymifolia (leonotin, leonotinin and nepetaefolin) and six other related compounds (hispanolone, 7α‐ and 7β‐hispanols, marrubiin, villenol and andalusol), previously isolated from Labiatae species, are presented. The assignments are based on 2D shift‐correlated [¹H, ¹H‐COSY, ¹H, ¹³C‐gHSQC–¹J(C,H), ¹H,¹³C‐gHMBC–ⁿJ(C,H) (n = 2 and 3)] and DPFGSE 1D‐NOE experiments. Copyright © 2003 John Wiley & Sons, Ltd.     

Complete assignments of 1H and 13C NMR data for new dibenzocyclooctadiene lignans from Kadsura oblongifolia

Two new dibenzocyclooctadiene lignans, named kadoblongifolins A (1) and B (2), and one new natural product dibenzocyclooctadiene lignan, named kadoblongifolin C (3), were isolated from the stems of Kadsura oblongifolia (K. oblongifolia), together with five known ones, schizanrin F (4), propinquanin C (5), schisantherin G (6), heteroclitin Q (7), kadsurarin (8). The structures of these new lignans were elucidated by a combination of high‐resolution electron ionization mass spectrometry (HR‐EI‐MS), ¹H NMR, ¹³C NMR, HMQC, HMBC, and NOESY spectra. Copyright © 2009 John Wiley & Sons, Ltd.     

1H and 13C NMR spectral assignments and conformational analysis of 14 19-nor-neoclerodane diterpenoids

Unambiguous and complete assignments of 1H and 13C NMR chemical shifts for 14 19-nor-neoclerodane diterpenoids, nine of them isolated from natural sources and five other synthetic derivatives, are presented. The assignments are based on 2D shift-correlated (1H,1H-COSY, 1H,13C-gHSQC and 1H,13C-gHMBC) and NOE experiments. The conformations of rings A and B of these compounds are supported by the 3J(H,H) values and they agree with the low-energy conformations obtained by semi-empirical calculations. Moreover, the data obtained in this work for 2-acetoxyteucvidin and a semisynthetic 18-aldehyde derivative indicate that the configuration at C-2 of the former and at C-10 of the latter must be reversed with respect to those reported previously.     

Complete assignments of the 1H and 13C NMR spectra of five rearranged abietane diterpenoids

An NMR study of five highly functionalized and rearranged abietane diterpenoids is described. In addition to 1D NMR methods, including 1D NOESY spectra, 2D shift‐correlated experiments [¹H, ¹³C‐gHSQC‐¹J (C,H) and ¹H, ¹³C‐gHMBC‐ⁿJ (C,H) (n = 2 and 3)] were used for the complete and unambiguous ¹H and ¹³C chemical shift assignments of these substances. Copyright © 2002 John Wiley & Sons, Ltd.     

Complete 1H and 13C data assignments of two new guaianolides isolated from Ainsliaea fragrans

Two new guaianolides, 8alpha-hydroxy-11alpha,13-dihydroglucozaluzanin C and 11alpha,13-dihydroglucozaluzanin C, were isolated from Ainsliaea fragrans, along with two known guaianolides, 8alpha-hydroxy-11alpha,13-dihydrozaluzanin C and glucozaluzanin C. The structures of the new compounds were unambiguously established by HR-ESI-MS, one-dimensional (1D) (DEPT), two-dimensional (2D) ((1)H-(1)H COSY, HSQC, HMBC, ROESY) NMR experiments and by comparison with structurally related compounds. The known compounds were identified by comparison of spectral data with published references. Some NMR data of the known compounds were reported for the first time.     

Complete assignments of 1H and 13C NMR data for three new arylnaphthalene lignan from Justicia procumbens

Three new arylnaphthalene lignans, named neojusticin C (1), procumbenoside C (2) and procumbenoside D (3), have been isolated from the whole plant of Justicia procumbens, together with three known ones, justicidinoside B (4), justicidinoside C (5), and diphyllin-1-O-beta-D-apiofuranoside (6). The complete assignments of 1H and 13C NMR data for three new lignans were first obtained by means of 2D NMR techniques, including HSQC and HMBC.     

1H and 13C NMR assignments for two new cordiaquinones from roots of Cordia leucocephala

From the roots of Cordia leucocephala (Boraginaceae), two new meroterpenoid naphthoquinones, 6‐[10‐(12,12‐dimethyl‐13α‐hydroxy‐16‐methenyl‐cyclohexyl)ethyl]‐1,4‐naphthalenedione (cordiaquinone L) and 5‐methyl‐6‐[10‐(12,12‐dimethyl‐13β‐hydroxy‐16‐methenyl‐cyclohexyl)methyl‐1,4‐naphthalenedione (cordiaquinone M) were isolated. Their structures were elucidated after detailed 1D and 2D NMR (COSY, HSQC, HMBC and NOESY) data analyses and comparison with literature data for analogous compounds. Copyright © 2008 John Wiley & Sons, Ltd.     

Complete assignments of 1H and 13C NMR spectroscopic data for three new stigmastane glycosides from Vernonia cumingiana

Three new steroidal saponins, Vernoniosides S1 ( 1 ), Vernoniosides S2 ( 2 ) and Vernoniosides S3 ( 3 ) were isolated from the stem of Vernonia cumingian. Their chemical structures were elucidated on the basis of MS, NMR spectroscopic and chemical analysis. Complete assignment of ¹H and ¹³C NMR spectroscopic data were achieved by 1D and 2D NMR experiments (HMQC, HMBC, ROESY). Copyright © 2008 John Wiley & Sons, Ltd.