Synthesis and spectral characteristics of N-(2,2,2-trichloro-1-((5-(methylthio)-1,3,4-thiadiazol-2-yl)amino)ethyl)carboxamides

Fifteen steroidal and phenolic compounds were previously isolated and identified from the EtOAc fraction of flowers of Apocynum lancifolium (Apocynaceae) collected in Xinjiang-Uyghur Autonomous Region, PRC [1]. In continuation of research on the chemical composition of flowers of A. lancifolium, we chromatographed the n-BuOH fraction over a column of AB-8 macroporous resin. Compounds were eluted sequentially by H2O and EtOH (30 and 80%). The two fractions obtained using EtOH (30 and 80%) were rechromatographed over a column of ODS-A 120c (octadecylsilyl silica gel) using MeOH–H2O mixtures (20, 40, 60, and 80% and MeOH) to produce five fractions. The eluates of all fractions were separated by chromatography over a column of Sephadex LH-20 using MeOH–H2O (1:1) and MeOH to isolate six known pure compounds, the chemical structures of which were elucidated using PMR, 13C NMR, and 2D spectra in addition a comparison with the literature. Umbelliferone (1). Colorless crystals, C9H6O3, mp 230°C. Compound 1 was identified as umbelliferone using spectral data [2]. Protocatechoic acid (3,4-dihydroxybenzoic acid) (2), C7H6O4, mp 200–202°C. Spectral data agreed with those published [3]. 1-(3,4-Dihydroxycinnamoyl)-cyclopentane-2 ,3 -diol (3). Light-yellow crystals, C14H16O6, [ ]D 20 –54.0° (c 0.1, DMSO), mp 128–130°C. 1H NMR spectrum (600 MHz, DMSO-d6, , ppm, J/Hz): 7.45 (1I, d, J = 15.8, H-7), 7.08 (1H, d, J = 1.7, H-2), 6.97 (1I, dd, J = 8.2, 1.7, H-6), 6.77 (1I, d, J = 8.2, H-5), 6.23 (1H, d, J = 15.8, H-8), 5.19 (1H, m, H-1 ), 3.94 (1H, br.s, H-3 ), 3.50 (1H, dd, J = 9.7, 2.3, H-2 ), 1.99 (1H, d, J = 12.2, H-4 ), 1.85 (2H, m, H-5 ), 1.70 (1H, m, H-4 ). 13C NMR spectrum (150 MHz, DMSO-d6, , ppm): 166.34 (N-9), 148.60 (N-4), 145.79 (N-3), 144.71 (N-7), 125.46 (N-1), 121.21 (N-6), 115.87 (N-5), 114.77 (N-2), 114.52 (N-8), 73.13 (N-2 ), 71.43 (N-1 ), 71.30 (N-3 ), 39.37 (N-5 ), 37.94 (N-4 ) [4]. L-Bornesitol (4). White crystals, C7H14O6, mp 210–212°C, [ ]D 20 –19.0° (c 0.1, DMSO). 1H NMR spectrum (600 MHz, DMSO-d6, , ppm, J/Hz): 4.58 (1I, d, J = 4.2, 5-II), 4.55 (1I, d, J = 4.5, 6-II), 4.51 (1I, d, J = 4.3, 4-II), 4.46 (1I, d, J = 3.6, 2-II), 4.40 (1I, d, J = 5.6, 3-II), 3.92 (1I, dd, J = 3.6, 2.6, I-2), 3.43 (1I, td, J = 9.4, 4.5, I-6), 3.34 (1I, td, J = 9.4, 4.3, I-4), 3.29 (3I, s, OCH3), 3.10 (1I, ddd, J = 9.7, 5.6, 2.6, I-3), 2.91 (1I, td, J = 9.3, 4.2, I-5), 2.82 (1I, dd, J = 9.7, 2.6, I-1). 13C NMR spectrum (150 MHz, DMSO-d6, , ppm): 81.71 (N-1), 68.31 (N-2), 71.73 (N-3), 72.49 (N-4), 75.32 (N-5), 71.81 (N-6), 56.65 (OCH3) [5]. 2D NOESY: H-1/H-3; 3-OH/6-OH, 5-OH, 4-OH; 4-OH/6-OH, 5-OH, 3-OH; 5-OH/6-OH, 4-OH, 3-OH; 6-OH/5-OH, 4-OH, 3-OH. Trifolin (kaempferol-3-O-D-galactoside) (5). Yellow powder, C21H20O11, mp 256–257°C. Acid hydrolysis of 5 produced kaempferol and -D-galactose. 1H NMR spectrum (600 MHz, DMSO-d6, , ppm, J/Hz): 8.07 (1H, d, J = 8.9, H-2 , 6 ), 6.86 (2H, d, J = 8.9, H-3 , 5 ), 6.42 (1H, d, J = 2.0, H-8), 6.19 (1H, d, J = 2.0, H-6), 5.40 (1H, d, J = 7.7, H-1 ), 3.66 (1H, br.s, H-4 ), 3.54 (1H, t, J = 8.6, H-2 ), 3.46 (1H, dd, J = 10.4, 6.0, H-6 ), 3.37 (1H, dd, J = 9.5, 3.0, H-3 ), 3.34 (1H, t, J = 6.0, H-5 ), 3.30 (1H, dd, J = 10.4, 6.0, H-6 ). 13C NMR spectrum (150 MHz, DMSO-d6, , ppm): 177.44 (C-4), 164.60 (C-7), 161.17 (C-5), 159.94 (C-4 ), 156.40 (C-9), 156.24 (C-2), 133.19 (C-3), 130.94 (C-2 ), 120.86 (C-1 ), 115.03 (C-3 ), 103.76 (C-10), 101.69 (C-1 ), 98.79 (C-6), 93.70 (C-8), 75.76 (C-5 ), 73.08 (C-3 ), 71.19 (C-2 ), 67.86 (C-4 ), 60.17 (C-6 ) [6].

Synthesis, characterizations and conformational analysis of some new 2-arylidene N-(1,3-dioxoisoindolin-2-yl)aminothiocarbohydrazides and their conversion to functionalized hybrids of isoindole core with thiadiazoline

The assignment of the signals in the 13C and 1H NMR spectra of N‐phenyl‐2,4‐dimethylbuta‐1,3‐diene‐1,4‐sultam is difficult for the signal pairs C‐2 and C‐4, C‐1 and C‐3, (C‐1)H, (C‐2)CH3 and (C‐4)CH3. The 13C NMR spectrum recorded under gated decoupling conditions provide long‐range couplings which make possible an unambiguous assignment of the 13C NMR signal pairs. Application of the 1H CW off‐resonance decoupling technique in recording the 13C NMR spectra enables the assignment information from the 13C NMR spectrum to be transferred to the 1H NMR spectrum.

Various pulse techniques of NMR spectroscopy were applied to CR to assign some small signals in 13C and 1H NMR spectra for the rubber. First, the rubber was subjected to distortionless enhancement by polarization transfer and attached proton test. The small signals in the 13C NMR spectrum were assigned to secondary, tertiary, and quaternary carbons. Second, correlations between 13C and 1H were investigated by heteronuclear multiple quantum correlation, heteronuclear two bond correlation, and heteronuclear multiple bond correlation measurements to assign the small signals in the 13C NMR spectrum in detail. By using the resulting correlations between 13C and 1H, the small unassigned signals in 1H NMR spectrum were assigned to methylene and methine protons of the rubber.

The western diet is poor in n-3 fatty acids, therefore the consumption of fish oil supplements is recommended to increase the intake of these essential nutrients. The objective of this work is to demonstrate the qualitative and quantitative analysis of encapsulated fish oil supplements using high-resolution 1H and 13C NMR spectroscopy utilizing two different NMR instruments; a 500 MHz and an 850 MHz instrument. Both proton (1H) and carbon (13C) NMR spectra can be used for the quantitative determination of the major constituents of fish oil supplements. Quantification of the lipids in fish oil supplements is achieved through integration of the appropriate NMR signals in the relevant 1D spectra. Results obtained by 1H and 13C NMR are in good agreement with each other, despite the difference in resolution and sensitivity between the two nuclei and the two instruments. 1H NMR offers a more rapid analysis compared to 13C NMR, as the spectrum can be recorded in less than 1 min, in contrast to 13C NMR analysis, which lasts from 10 min to one hour. The 13C NMR spectrum, however, is much more informative. It can provide quantitative data for a greater number of individual fatty acids and can be used for determining the positional distribution of fatty acids on the glycerol backbone. Both nuclei can provide quantitative information in just one experiment without the need of purification or separation steps. The strength of the magnetic field mostly affects the 1H NMR spectra due to its lower resolution with respect to 13C NMR, however, even lower cost NMR instruments can be efficiently applied as a standard method by the food industry and quality control laboratories.

Upcycling Polytetrahydrofuran to Polyester

A series of derivatives with various oxygen functionalities in positions 17,22a or 19,20 was prepared from diene I and olefin XVI by addition and oxidation reactions. The structure of the obtained compounds was confirmed by 1H NMR, 13C NMR and IR spectroscopy. The kind of intramolecular association of the 17α-hydroxy group was studied in connection with modification of the side chain and substitution in position 22a. Complete assignment of the hydrogen signals and most of the coupling constants was accomplished using a combination of 1D and 2D NMR techniques. The 1H and 13C NMR spectra are discussed.

The development of chromofluorogenic sensors for anions is a well-established and studied field in the supramolecular chemistry realm.1 This is due to the important roles of anions in biological processes, deleterious effects (such as environmental pollutants), and as toxic compounds and carcinogenic species.2

Actinomycetes are well recognized as the richest source of bioactive compounds, including clinically important antibiotics, antitumor agents and cell function modulators, and hence of high pharmacological and commercial interest.1 Amongst this group, members of the genus Streptomyces are the most prolific producers of secondary metabolites, accounting for up to 80% of the bioactive small molecules discovered from actinomycetes.2 Meanwhile, it is quite notable that further discovery of unknown metabolites from Streptomyces is predicted by the genome analysis: the number of metabolites actually isolated is far more below the number of secondary metabolite biosynthetic gene clusters identified in the whole genomes of S. avermitilis and S. coelicolor.3,4 As a part of our chemical investigation on microbial secondary metabolites, we reported plant-growth promoting spiroacetals of polyketide origin,5 a linear polyketide with a dlactone terminus with cytotoxic activity,6 a polycyclic tetronate with antiinvasive activity7 and a biosynthetically unprecedented heterocyclic polyketide with antibacterial and antiinvasive activities8 from Streptomyces. During the course of our continuing effort to discover structurally unique secondary metabolites from these organisms, a new modified peptide was isolated from the culture broth of a soilderived actinomycete strain Streptomyces sp. SPMA113 collected in Thailand. The strain was cultured in A-11M liquid medium, and the whole culture broth was extracted with 1-butanol. The HPLC/UV analysis of the extract using our in-house metabolite database indicated the presence of an unknown compound showing a UV absorption maximum at 260nm, along with geldanamycins9 and elaiophylins.10 Guided by HPLC/UV, several steps of chromatographic purification resulted in the isolation of a new compound, prajinamide (1, Figure 1). Compound 1 was obtained as a pale yellow oil that analyzed for a molecular formula of C16H25N3O3 (6 degrees of unsaturation) by interpretation of HR–ESI–TOF–MS (observed [M+Na]+ at m/z 330.1788, calculated [M+Na]+ 330.1788). This molecular formula was corroborated by 1H and 13C NMR spectral data (Table 1). Analysis of the combined 1D and 2D NMR data established that 1 possessed three carbonyl, four olefinic methine, two sp3 methine, five sp3 methylene and two methyl carbons, in addition to three exchangeable protons. The IR absorptions at 1647, 1599 and 1538 cm 1 indicated the presence of amide functionalities, which was supported by the resonances of carbonyl carbons at d 165.6, 169.9 and 170.1 observed in the 13C NMR spectrum. As three carbonyls and two double bonds accounted for five of six double-bond equivalents, 1 must be a monocyclic compound. Further analysis of 1H-1H COSYand HMBC spectra provided three substructures (Figure 2). The first was an ornithine lactam that was established by the sequential COSY correlations from an NH proton at d 7.61 (2-NH) to another NH proton at d 8.07 (5-NH) through a methine proton (H-2) and three methylene protons (H-3, H-4 and H-5) and HMBC correlations from H-2, H-3, H-5 and 2-NH to a carbonyl carbon C-1 (d 169.9). The second substructure, a b-alanine, was assigned on the basis of COSY correlations between an NH proton at d 7.98 (8-NH) and H-8 and between H-8 and H-7 and HMBC correlations from H-7 and H-8 to C-6 (d 170.1). Two and three-bond C–H correlations from 2-NH and H-2 to C-6 allowed the b-alanine residue being connected to the ornithine lactam through an amide linkage. COSY correlations between four olefinic protons H-10, H-11, H-12 and H-13 provided a conjugated diene, which was then extended to include a carbonyl carbon C-9 (d 165.6) at C-10 on the basis of HMBC correlations from H-10 and H-11 to C-9. A vinyl methine H-13 showed a COSY correlation to H-14, which showed in turn correlations to two equivalent methyl protons H-15 and H-16, thereby establishing an isopropyl terminus attached to the diene fragment. The geometries of C-10–C-11 and C-12–C-13 double bonds were assigned as Z and E, respectively, on the basis of the vicinal coupling constants (JH10,H111⁄411.3Hz, JH12,H131⁄415.5Hz). The third substructure was thus

Synthesis, spectral characterisation of 2-(5-methyl-1 H-benzimidazol-2-yl)-4-bromo/nitro-phenols and their complexes with zinc(II) ion, and solvent effect on complexation

Analysis of the 13C and 1H NMR spectra of phenol-formaldehyde resole oligomers

The structural and spectroscopic investigation of 2-chloro-3-methylquinoline by DFT method and UV–Vis, NMR and vibrational spectral techniques combined with molecular docking analysis

Syntheses and NMR studies of five-co-ordinate rhodium(I) complexes with α-diimines (RNC(H)C(H)NR): [RhCl(CO)(η 2-C 2H 4)(α-diimine)] and [RhCl(L) 2(α-diimine)] (R = t−Bu, EtMe 2C−; L = CO,PF 3)

The benzimidazole derivatives have been obtained via weightreducing aid (L-Carnitine) as a cheap catalyst. A wide range of aromatic aldehydes easily undergo condensations with substituted o-phenylendiamine under mild condition to afford the target molecular in excellent yields. Melting points were measured on an Electrothemal X6 microscopy digital melting point apparatus. 1H NMR and 13C NMR spectra were recorded in DMSO-d6 on a Bruker AVANCE 400 (400 MHz) instrument with the TMS at d 0.00 ppm as an internal standard. C, H and N analysis were performed by a Perkin-Elmer 2400 CHN elemental analyzer. Chemicals used were of commercial grade without further purification. An equimloar (1.0 mmol) mixture of o-phenylenediamine 1, aromatic aldehyde 2, and L-Carnitine (10 mol%) was vigorously stirred at 60°C in EtOH (3 mL) for the specific time indicated by TLC (petroleum: ethyl acetate ether = 4:1). After completion of the reaction, the mixture was quenched by adding H2O (20 mL), extracted with EtOAc (3 x 10 mL), and the combined extracts were dried by anhydrous MgSO4. The filtrate was evaporated and the corresponding benzimidazole was obtained as the only product. The products 3a-3r were obtained in 82-95% yields. The structures of the products 3 were identified by their IR, 1H NMR, 13C NMR and elemental analysis spectra. The products were obtained in 82-95% yields in 30-80 min. The method has several advantages such as simple, clean and environmentally process, excellent yield and avoiding use of inconvenient preparation of catalyst. Meanwhile, the catalyst L-Carnitine is a kind of weightreducing aid, which might be applied to broad green catalyzed system. A facile synthesis of benzimidazoles comprising the reaction of various aldehydes with substituted o-phenylendiamine in good to excellent yield is provided using L-Carnitine as an efficient catalyst. The protocol overcomes the earlier disadvantages like harsh reaction conditions, tedious work-up, expensive process, wastes generation and the use of metallic oxide, which might be applied to the synthesis of benzimidazoles pharmaceticals in order to meet friendly environmental demands.

Synthesis and in silico studies of Novel Ru(II) complexes of Schiff base derivatives of 3-[(4-amino-5-thioxo-1,2,4-triazole-3-yl)methyl]-2(3H)-benzoxazolone compounds as potent Glutathione S-transferase and Cholinesterases Inhibitor