Dicondensed indolinobenzospiropyrans as precursors of thermo- and photochromic spiropyrans. Part II: Assignment of (1)H and (13)C NMR spectra

The (1)H and (13)C NMR spectra of dicondensed indolinobenzospiropyrans as precursors of thermo- and photochromic spiropyrans, DC1-DC5, were completely assigned. Especially, the (1)H assignment and coupling characteristics of the diastereotopic protons at the carbon-3 position of the benzopyran rings were achieved by conducting (1)H-(1)H COSY and nOe experiments. The dihedral angles (theta(1), theta(2) and theta(3)) calculated from the experimental values of the vicinal coupling constants ((3)J) of DC5 are in good agreement with the observed values in the solid state. All of the carbons in the DC dye molecules were investigated through a combination of heteronuclear 2D-shift correlation spectroscopy (HETCOR) and DEPT135.     

Enantioselective self-assembly of bimetallic [Mn(II) (delta)-Cr(III)(C2O4)3]- and [Mn(II) (lambda)-Cr(III)(C2O4)3]- layered anionic networks templated by the optically active (Rp)- and (Sp)-[1-CH2N(n-C3H7)3-2-CH3-C5H3Fe-C5H5]+ ions

The ferrocenic ammonium (Rp)- and (Sp)-[1-CH2NR(3-)-2-CH3-C5H3Fe-C5H5] iodide salts with R=CH3, C2H5, n-C3H7, n-C4H9, were synthesized starting from the (Rp)- and (Sp)-[1-CH2N(CH3)2-2-CH3-C5H3Fe-C5H5] amines obtained in their optically active forms through asymmetric cyclopalladation of [C5H5Fe-C5H4CH2N(CH3)2]. 1H NMR studies of these planar chiral 1,2-disubstituted ferrocenic ammonium iodide salts in the presence of the (Delta)-(tris(tetrachlorobenzenediolato)phosphate(V) anion), [(Delta)-Trisphat] support the formation of specific diastereomeric ion pairs. Such intermolecular interactions can be related to the self-assembly of the two-dimensional optically active compounds [[(Sp)-1-CH2N(n-C3H7)3-2-CH3-C5H3Fe-C5H5][Mn (Delta)-Cr(C2O4)3]] and [[(Rp)-1-CH2N(n-C3H7)3-2-CH3-C5H3Fe-C5H5][Mn (Lambda)-Cr(C2O4)3]] starting from the resolved (Rp)- and (Sp)-[1-CH2N(n-C3H7)3-2-CH3-C5H3Fe-C5H5]+ ion associated to the racemic anionic building block rac-[Cr(C2O4)3]3- and Mn2+. Both enantiomeric forms of the networks behave as ferromagnets with a Curie temperature of 5.7 K.     

1H and 13C NMR assignments for new heterocyclic TAM leuco dyes, (2Z,2'E)-2,2'-(2-phenyl propane-1,3-diylidene) bis(1,3,3-trimethylindoline) derivatives. Part II

The (1)H and (13)C NMR spectra of the novel heterocyclic Leuco-TAM dyes, (2Z, 2'E)-2,2'-(2-phenyl propane-1,3-diylidene) bis(1,3,3-trimethylindoline) derivatives 1-4 as precursors of triarylmethane (TAM)(+) (Malachite Green FB-analog) dyes were completely assigned by 1D and 2D NMR experiments, including DEPT, COSY, HSQC, HMBC, and NOESY. Especially, the diastereotopic gem-dimethyl protons at the C3 and C3' positions of the FB rings were definitively assigned. The (Z,E) isomers adopt the energetically favored three-bladed propeller conformation in solution.     

Structure and absolute configuration of hydroxy‐bis‐dihydrofarinosin from Encelia farinosa

The structure of the dimeric eudesmanolide hydroxy‐bis‐dihydrofarinosin ( 1 ) from Encelia farinosa followed after contrasting their ¹H and ¹³C NMR spectra with those of encelin ( 6 ), hydroxy‐bis‐dihydroencelin ( 3 ), and farinosin ( 4 ). Structure  1 was verified by single‐crystal X‐ray diffraction analysis, which further provided the stereochemistry of the hydroxy group at C‐4. Comparison of the experimental vibrational circular dichroism spectrum of its derived diacetate 2 with that calculated by density functional theory provided the absolute configuration, which resulted the same as that of its biogenetic precursor 4 . Evaluation of several chemical shift differences between the two eudesmanolide fragments of 1 and 3 allows also ascertaining the yet not reported absolute configuration of the C‐4 stereogenic center of 3 . Copyright © 2016 John Wiley & Sons, Ltd.     

Assignments of 1H and 13C NMR spectral data for ondansetron and its two novel metabolites, 1-hydroxy-ondansetron diastereoisomers

Assignments of 1H and 13C NMR chemical shifts were made by means of heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) experiments for ondansetron, and by means of 1H-1H correlation spectroscopy (1H-1H COSY) and two-dimensional nuclear Overhauser effect spectroscopy (NOESY) experiments for two novel metabolites (M1 and M2) of ondansetron. These two metabolites were isolated for the first time from Mucor circinelloides.     

Complete and unambiguous assignments of 1H and 13C chemical shifts of new arylamino derivatives of ortho-naphthofuranquinones

Six new nor-beta-lapachones have been synthesized from reaction of 3-bromo-nor-beta-lapachone with arylamines. These derivatives have potent anticancer properties against several cell lines. Here, we report complete unambiguous assignments of (1)H and (13)C chemical shifts of the new compounds. The assignments were made using a combination of one- and two-dimensional NMR techniques ((1)H, (13)C, (1)H-(1)H COSY, (1)H-(13)C HSQC, and (1)H-(13)C HMBC).     

Synthesis of Novel Photochromic 6‐Benzyloxo‐spirobenzopyran Compounds

The synthesis of four novel derivatives of 1′,3′,3′‐trimethylspiro‐[2H‐1]‐benzopyran‐6‐benzyloxo‐2,2′‐indoline is reported. The synthetic approach to these compounds involves the preparation of the key compound, 3‐formyl‐4‐hydroxybenzophenone, by means of the Reimer–Tiemann reaction. The photochromic compounds were isolated and characterized by ¹H and ¹³C NMR as well as FT‐IR and UV‐VIS spectrometry. Comparative studies performed in these compounds showed a higher molar extinction coefficient and red shift of maximum absorption wavelength when the benzyloxo group is introduced in the spirobenzopyran molecule.     

Isolation and spectral study of 4‐methyl‐6,8‐dihydroxy‐7H‐benz[de]anthracen‐7‐one

4‐Methyl‐6,8‐dihydroxy‐7H‐benz[de]anthracen‐7‐one was isolated from the sap of Aloe by column chromatography. Its ¹H and ¹³C NMR spectra were completely assigned by utilizing two‐dimensional ¹H‐detected heteronuclear one‐bond (HMQC) and multiple‐bond (HMBC) chemical shift correlation experiments together with ¹H–¹H COSY and DEPT techniques. These techniques were also valuable in assigning the protons and carbons of those benzanthrone compounds which were previously incompletely reported because of the overlap of proton signals. The molecular structure was elucidated by 2D NMR analysis. The spectral properties (MS, IR and UV) are also presented. Copyright © 2003 John Wiley & Sons, Ltd.     

19F and 1H NMR spectra of halocarbons

19F NMR chemical shifts and coupling constants are reported for 215 compounds. For 77 of these compounds, 1H NMR spectral data are also given. Long-range couplings, including 8J(F,F) and 5J(F,H), are reported. The complexity of halocarbon spectra owing to the presence of rotational isomers, asymmetric centers, long-range couplings, and chlorine isotope effects are illustrated, and the methods used for analyzing such complex spectra are briefly discussed.     

Study of spontaneous E/Z isomerization of bis[(Z)‐cyanomethylidene]‐diazapentacyclodienedicarboxylates by 1H, 13C,and 15N NMR spectroscopy,X‐ray,and quantum chemical calculation data

X‐ray data show that the diethyl 6,13‐bis[(Z)‐cyanomethylidene]‐5,5,14,14‐tetramethyl‐4,15‐dioxa‐7,12‐diazapentacyclo[9.5.2.0^2,10.0^3,7.0^12,16]octadeca‐8,17‐diene‐10,17‐dicarboxylate is formed as the ZZ isomer and diastereomer with the (1R*,2R*,3R*,10S*,11R*,12R*,16R*) configuration. The ¹H, ¹³C, and ¹⁵N NMR data exhibit that on standing in chloroform‐d solution, there is a spontaneous isomerization of this compound resulting in a thermodynamically stable mixture of the ZZ, ZE, EE, and EZ isomers with the same backbone. Using the 2D [¹H–¹H] COSY, [¹H–¹³C] HSQC, and [¹H–¹³C, ¹H–¹⁵N] HMBC NMR techniques and quantum chemical calculations makes it possible a complete assignment of signals in the ¹H, ¹³C, and ¹⁵N NMR spectra of each of the isomers. Such isomerization does not occur for similar compounds with the more bulky substituents at the 1,3‐oxazolidine rings. Copyright © 2016 John Wiley & Sons, Ltd.     

Complete 1H and 13C assignments of 8-C-beta-D-[2-O-(E)-p-coumaroyl]glucopyranosyl-2-(2-hydroxy)propyl-7-methoxy-5-methylchromone

1H and 13C NMR spectra of 8-C-beta-D-[2-O-(E)-p-coumaroyl] glucopyranosyl-2-(2-hydroxy)propyl-7-methoxy-5-methylchromone were completely assigned by 2D NMR observations. Especially the 1H assignments of the glucosyl and hydroxyl protons were achieved by utilizing HMQC, HMBC, 1H-1H COSY and DEPT techniques together with a heavy water exchange 1H NMR experiment.     

Complete assignment of NMR data of 22 phenyl‐1H‐pyrazoles' derivatives

Complete assignment of ¹H and ¹³C NMR chemical shifts and J(¹H/¹H and ¹H/¹⁹F) coupling constants for 22 1‐phenyl‐1H‐pyrazoles' derivates were performed using the concerted application of ¹H 1D and ¹H, ¹³C 2D gs‐HSQC and gs‐HMBC experiments. All 1‐phenyl‐1H‐pyrazoles' derivatives were synthesized as described by Finar and co‐workers. The formylated 1‐phenyl‐1H‐pyrazoles' derivatives were performed under Duff's conditions. Copyright © 2011 John Wiley & Sons, Ltd.     

1H and 13C NMR studies of 2-functionalized 5-(methylsulfonyl)-1-phenyl-1H-indoles

The 1H and 13C NMR resonances of thirty 2-functionalized 5-(methylsulfonyl)-1-phenyl-1H-indoles were assigned completely and unequivocally using the concerted application of one- and two-dimensional experiments (DEPT, gs-HMQC and gs-HMBC). Finally, the influence of the 2-substituent of 5-(methylsufonyl)-1-phenyl-1H-indoles on the carbon atoms of the indole moiety was estimated.     

(1)H and (13)C NMR studies of asymmetrically substituted bis- and tris-Tröger's bases

The (1)H and (13)C NMR spectra of two stereoisomeric bis-Tr?ger's bases and four stereoisomeric tris-Tr?ger's bases asymmetrically substituted on the external aromatic rings were recorded and the corresponding signals assigned. The relative configuration of the stereogenic units has been unequivocally determined on the basis of homoallylic couplings and NOE experiments.     

Multinuclear magnetic resonance analysis of 2-(trifluoromethyl)-2-oxazoline

(1)H, (19)F, (13)C, (15)N, and (17)O NMR chemical shifts and (1)H-(1)H, (1)H-(19)F, (1)H-(13)C, (19)F-(13)C, and (19)F-(15)N coupling constants are reported for 2-(trifluoromethyl)-2-oxazoline.     

Diastereoisomerism of thiol complexes of arsenic acids and pseudoasymmetry of arsenic: a 1H and 13C NMR study

Diastereoisomeric complexes of methylphenylarsinic acid and (L)-glutathione could be partially separated by HPLC, but the separated compounds rapidly racemized, presumably by pyramidal inversion at the arsenic atom. Hydrolysis of the diastereoisomeric complexes yielded methylphenylarsinous acid as a pair of enantiomers revealed by a 1H NMR study with an asymmetric lanthanide shift reagent. Methylphenylarsinous acid was also synthesized as an enantiomeric pair, shown by an asymmetric shift reagent experiment, by the hydrolysis of iodomethylphenylarsine. 1H and 13C NMR spectroscopy were used to demonstrate that complexing of phenylarsonic acid with (R,S)-3-mercapto-1,2-propanediol and with (R,S)-1-mercapto-2-propanol yielded, in each case, a pair of enantiomers, PhAs[(R)-ligand)]2, PhAs[(S)-ligand)]2, in which the homomorphic ligands were diastereotopic, and a pair of diastereoisomers, PhAs[(R)-ligand][(S)-ligand], which differed from each other in the configuration about the pseudoasymmetric arsenic atom.     

1H and 13C spectral assignment of substituted 5H-[1,3]thiazolo[2,3-b]quinazolin-5-one and 12H-[1,3]benzothiazolo[2,3-b] quinazolin-12-one

(1)H and (13)C spectroscopic data for 5H-[1,3]thiazolo[2,3-b]quinazolin-5-one and 12H-[1,3]benzothiazolo[2,3-b]quinazolin-12-one derivatives were fully assigned by combination of one- and two-dimensional experiments (DEPT, HMBC and HMQC). Both heterocyclic systems show similar spectroscopic properties with some remarkable differences.     

Conformational analysis. Part 40: a theoretical and NMR investigation of the conformations of cis‐ and trans‐cyclopentane‐1,3‐diol

The conformations of cis‐ ( 1 ) and trans‐cyclopentane‐1,3‐diol ( 2 ) have been studied by ab initio (Gaussian 98) and molecular mechanics (PCMODEL) calculations and by NMR spectroscopy. The calculations gave two low‐energy conformations for ( 1 ), 1A and 1B , both with axial hydroxyl groups. Two conformations with equatorial hydroxyl groups ( 1C and 1D ) were found but with much higher energy (ca 4.0 kcal mol^?1). Five low‐energy conformers were found for 2 . Four were envelope conformations and one a half‐chair. The complete analysis of the 400 MHz ¹H NMR spectra of 1 in a variety of solvents and 2 in chloroform was performed by extensive decoupling experiments, iterative computer analysis and spectral simulation. This gave all the H,H couplings in the molecule, including in 1 a long‐range ⁴J(H,H) coupling between H‐2cis and H‐4,5cis. The ³J(H,H) couplings were used to determine the conformer populations in these molecules. This was initially achieved using the Haasnoot, de Leeuw and Altona equation. to obtain the conformer couplings. It was found that this equation was not accurate for the C·CH₂·CH₂·C fragment in these molecules and the following equation was derived for this fragment from five‐ and six‐ membered cyclic compounds in fixed conformations: (1) The conformer populations were obtained by calculating the conformer couplings which were then compared with the observed couplings. Compound 1 in benzene solution is an approximately equal mixture of conformers 1A and 1B with small (<4%) amounts of 1C and 1D . In the polar solvents acetone and acetonitrile the populations of 1A and 1B are again equal, with 20% of 1C and <2% of 1D . In 2 the major conformers are 2B and 2D with small amounts of 2C , 2E and 2A . These novel findings are considered with previous data on cyclopentanol and cis‐ and trans‐cyclopentane‐1,2‐diol and it is shown that the axial hydroxyl substituent at the fold of the envelope appears to be a major factor in determining the conformational energies of these compounds. Copyright © 2003 John Wiley & Sons, Ltd.     

1H and 13C assignments of two new macrocyclic lactones isolated from Streptomyces sp. 211726 and revised assignments of azalomycins F3a, F4a and F5a

Azalomycin F(4a) 2-ethylpentyl ester (1) and Azalomycin F(5a) 2-ethylpentyl ester (2), two new macrocyclic lactones, along with three known compounds of Azalomycins F(3a) (3), F(4a) (4) and F(5a) (5), were identified from metabolites of Streptomyces sp. 211726 isolated from mangrove rhizosphere soil. The complete (1)H and (13)C assignments of these compounds were achieved by using (1)H, (13)C, DEPT, HSQC, (1)H-(1)H COSY and HMBC spectra, and the relative stereochemistry of 5 was first elucidated on the basis of proton-proton coupling constants, NOESY and IR spectra. Moreover, some errors in the (1)H and (13)C assignments published of 3, 4 and 5 were found and revised. 1 and 2 were active against Candida albicans, and exhibited moderate cytotoxicity against HCT-116 cell line.     

1H, 13C and 15N NMR spectral characterization of twenty-seven 1,2-diaryl-(4E)-arylidene-2-imidazolin-5-ones

1H, 13C and 15N NMR chemical shifts and couplings (n)J(H,C) in DMSO-d(6) at 30 degrees C have been determined for 1,2-diaryl-(4E)-arylidene-2-imidazolin-5-one derivatives 1-27. Their chemical shift assignments are based on PFG DQF 1H,1H COSY, PFG 1H,13C HMQC as well as PFG 1H,13C and 1H,15N HMBC experiments. For compounds 1-10 including aryl fluorine substituent(s) also the couplings (n)J(F,C) (n = 1 - 4) are reported.