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1.
A Facile Synthesis of Oxoindenothiazine and Dioxospiro(indene‐2,4′‐thiazine) Derivatives from (Substituted ethylidene)hydrazinecarbothioamides
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Alaa A. Hassan Yusria R. Ibrahim Essmat M. El‐Sheref Mahmoud A. A. Ibrahim Stefan Bräse 《Journal of heterocyclic chemistry》2015,52(4):1201-1207
(E)‐2‐[2‐(1‐Substituted ethylidene)hydrazinyl]‐5‐oxo‐9b‐hydroxy‐5,9b‐dihydroindeno[1,2‐d][1,3]‐thiazine‐4‐carbonitriles and (E)‐5‐oxo‐[(E)‐(1‐substituted ethylidene)hydrazinyl]‐2,5‐dihydroindeno[1,2‐d][1,3]thiazine‐4‐carbonitriles have been obtained from the reaction of 2‐(substituted ethylidene)hydrazinecarbothioamides with 2‐(1,3‐dioxo‐2,3‐dihydro‐1H‐inden‐2‐ylidene)propanedinitrile ( 1 ) in ethyl acetate solution. However, (Z)‐6′‐amino‐1,3‐dioxo‐3′‐substituted‐2′‐[(E)‐(1‐phenylethylidene)hydrazono]‐1,2′,3,3′‐tetrahydrospiro(indene‐2,4′‐[1,3]thiazine)‐5′‐carbonitriles were observed during the reaction of N‐substituted‐2‐(1‐phenylethylidene)hydrazinecarbothioamides with ( 1 ). The structure assignment of products has been confirmed on the basis of 1H‐, 13C‐NMR, and mass spectrometry, as well as theoretical calculations. 相似文献
2.
Mehdi Rimaz Nader Noroozi Pesyan Jabbar Khalafy 《Magnetic resonance in chemistry : MRC》2010,48(4):276-285
The tautomerism of the synthesized 3‐arylpyrimido[4,5‐c]pyridazine‐5,7(6H,8H)‐diones ( 1a–d ) and 3‐aryl‐7‐thioxo‐7,8‐dihydro‐6H‐pyrimido[4,5‐c]pyridazine‐5‐ones ( 2a–d ) was studied in dimethyl sulfoxide (DMSO)‐d6. 1H NMR spectra of 1a–d showed a clustered water molecule in the structure backbone that is attached by strong intermolecular H bonding. The relation between the temperature and H bonding of the clustered water molecule with 1a was also studied as representative. The relation between the electronegativity (χ) of the substituent on phenyl ring and the chemical shifts of clustered water protons in 1a–d was also studied. All of 1a–d and also 2d compounds existed in lactam ( I ) form, whereas 2a–c compounds have two distinguished tautomers in DMSO‐d6 [lactam ( I ) and lactim ( II ) forms]. The solvent‐substrate proton exchange was examined in compounds 1a–d and 2a–d by adding one drop of D2O. All compounds (except 1d ) showed proton/deuterium exchange of the clustered water protons in DMSO by adding one drop of D2O. Some compounds (but not all of them) that are easily soluble in DMSO‐d6 containing D2O showed isotopic splitting (β‐isotope effect) in their 13C NMR spectra. Among them, compound 1a was the best evidence to help the spectral assignments and structure determination of predominant tautomer by carbon‐13 splitting (β‐isotope effect). Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
3.
G. K. Pierens T. K. Venkatachalam D. Reutens 《Magnetic resonance in chemistry : MRC》2014,52(8):453-459
Ortho‐substituted and para‐substituted aminophenyl benzothiazoles were synthesised and characterised using NMR spectroscopy. A comparison of the proton chemical shift values reveals significant differences in the observed chemical shift values for the NH protons indicating the presence of a hydrogen bond in all ortho‐substituted compounds as compared to the para compounds. The presence of intramolecular hydrogen bond in the ortho amino substituted aminophenyl benzothiazole forces the molecule to be planar which may be an additional advantage in developing these compounds as Alzheimer's imaging agent because the binding to amyloid fibrils prefers planar compounds. The splitting pattern of the methylene proton next to the amino group also showed significant coupling to the amino proton consistent with the notion of the existence of slow exchange and hydrogen bond in the ortho‐substituted compounds. This is further verified by density functional theory calculations which yielded a near planar low energy conformer for all the o‐aminophenyl benzothiazoles and displayed a hydrogen bond from the amine proton to the nitrogen of the thiazole ring. A detailed analysis of the 1H, 13C and 15N NMR chemical shifts and density functional theory calculated structures of the compounds are described. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
4.
《Magnetic resonance in chemistry : MRC》2003,41(11):908-920
Structure elucidation of compounds in the benzisoxazole series ( 1 – 6 ) and naphtho[1,2‐d][1,3]‐ ( 7 – 10 ) and phenanthro[9,10‐d][1,3]oxazole ( 11 – 14 ) series was accomplished using extensive 2D NMR spectroscopic studies including 1H–1H COSY, long‐ range 1H–1H COSY, 1H–13C COSY, gHMQC, gHMBC and gHMQC‐TOCSY experiments. The distinction between oxazole and isoxazole rings was made on the basis of the magnitude of heteronuclear one‐bond 1JC2, H2 (or 1JC3, H3) coupling constants. Complete analysis of the 1H NMR spectra of 11 – 14 was achieved by iterative calculations. Gradient selected gHMQC‐TOCSY spectra of phenanthro[9,10‐d][1,3]oxazoles 11 – 14 were obtained at different mixing times (12, 24, 36, 48 and 80 ms) to identify the spin system where the protons of phenanthrene ring at H‐5, H‐6 and at H‐9 and H‐7 and H‐8 were highly overlapping. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
5.
A series of new substituted‐[1,2,4]oxadiazolo[5,4‐d][1,5]benzothiazepine derivatives containing pyrazole ring 4 / 4′ was synthesized by substituted‐pyrazolo[1,5]benzothiazepines 2 / 2′ and substituted‐benzohydroximinoyl chlorides 3 through the 1,3‐dipolar cycloaddition reaction in the presence of Et3N at room temperature, and characterized by MS, IR, 1H NMR and elemental analyses. In addition, the structure of 4′l was determined by X‐ray crystallography. J. Heterocyclic Chem., 2011. 相似文献
6.
Hao Gao Kui Hong Guo‐Dong Chen Chuan‐Xi Wang Jin‐Shan Tang Yang Yu Miao‐Miao Jiang Man‐Mei Li Nai‐Li Wang Xin‐Sheng Yao 《Magnetic resonance in chemistry : MRC》2010,48(1):38-43
Two new oxidized sterols 1 and 2 were obtained from the active fraction of a mangrove fungus Aspergillus awamori isolated from the soils around the mangrove plant Acrostichum speciosum. Their structures were elucidated using spectroscopic methods as 22E‐7α‐methoxy‐5α,6α‐epoxyergosta‐8(14),22‐dien‐3β‐ol (1) and 22E‐3β‐hydroxy‐5α,6α,8α,14α‐diepoxyergosta‐22‐en‐7‐one (2). The NMR data and complete assignments for both DMSO‐d6 and CDCl3 were given. Their cytotoxic activity against A549 cell line was evaluated. Furthermore, the detailed conformation analysis for ring B (cyclohexene oxide system) of sterol 1 was given on the basis of NOEs. The endo‐boat conformation was considered as the preferred conformation for ring B rather than half‐chair conformation. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
7.
Hisashi Saitoh Hisako K. Ijuin Nobuko Watanabe Masakatsu Matsumoto 《Helvetica chimica acta》2013,96(9):1704-1713
When treated with LiNiPr2 (LDA) at ?78°, 1‐[(methylsulfanyl)methyl]‐2‐[(1Z,3E)‐4‐phenylbuta‐1,3‐dien‐1‐yl]benzene easily cyclized to form benzocycloheptenyl anion, which successively underwent intramolecular nucleophilic substitution to give a cyclopropanaphthalene. Similar LDA‐mediated cyclization also occurred for 4‐phenyl‐ or 4‐methyl‐substituted 1‐[2‐(methoxymethyl)phenyl]buta‐1,3‐dienes to furnish the corresponding benzocycloheptenes and cyclopropanaphthalenes. A 4‐tert‐butyl analog also underwent LDA‐mediated cyclization to give a benzocycloheptene, but not a cyclopropanaphthalene. 相似文献
8.
Conjugated Dienyne‐Imides as Robust Precursors of 1‐Azatrienes for 6π Electrocyclizations to Furo[2,3‐b]dihydropyridine Cores
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Yanjun Wan Dr. Xuchun Zheng Prof. Dr. Cheng Ma 《Angewandte Chemie (International ed. in English)》2018,57(19):5482-5486
A novel strategy to generate functionalized 1‐azatriene intermediates for 6π electrocyclizations was developed by using readily accessible dienyne‐imides and various terminal olefins under PdII catalysis. Taking advantage of the sequential cooperation between preloaded and incorporated functional handles at 1,3‐dien‐5‐yne skeletons, this method not only enables the selective generation of putative 1‐azatrienes but significantly accelerates their thermal 6π‐electrocyclic ring‐closure processes to a series of highly substituted furo[2,3‐b]dihydropyridine derivatives in good yields. 相似文献
9.
Erich Kleinpeter 《Structural chemistry》1997,8(2):161-173
The results of NMR spectroscopic and X-ray crystallographic studies are critically discussed with respect to the structure of hydantoins, their tautomerism, and their acidity. The imide NH proton of the preferred, nearly planar 2,4-imidazolidine-dione tautomer proved to be more acidic than the corresponding amide NH proton. Phenyl substituents at the ring nitrogen atoms and at C-5 are twisted from the plane of the hydantoin ring; in case ofortho substituents restricted rotation about the N-aryl bond was found and the barrier to rotation determined by dynamic NMR spectroscopy. For 5-benzyl substituents, afolded conformation of the two rings, due to intramolecular interactions, was found and for 5-exo-methylene substituted hydantoins the relevant E/Z isomerism at theexo-cyclic C, C double bond was studied. In addition, the1H and13C chemical shifts of the hydantoins proved to excellently indicate the electronic distribution along the hydantoin ring moiety. Finally, the mass spectrometric fragmentation of the hydantoins is critically discussed.Dedicated to Prof. Rolf Borsdorf on the occasion of his 65th birthday. 相似文献
10.
The phenylimidorhenium(V) complexes [Re(NPh)X3(PPh3)2] (X = Cl, Br) react with the N‐heterocyclic carbene (NHC) 1,3‐diethyl‐4,5‐dimethylimidazole‐2‐ylidene (LEt) under formation of the stable rhenium(V) complex cations [Re(NPh)X(LEt)4]2+ (X = Cl, Br), which can be isolated as their chloride or [PF6]? salts. The compounds are remarkably stable against air, moisture and ligand exchange. The hydroxo species [Re(NPh)(OH)(LEt)4]2+ is formed when moist solvents are used during the synthesis. The rhenium atoms in all three complexes are coordinated in a distorted octahedral fashion with the four NHC ligands in equatorial planes of the molecules. The Re–C(carbene) bond lengths between 2.171(8) and 2.221(3) Å indicate mainly σ‐bonding between the NHC ligand and the electron deficient d2 metal atoms. Attempts to prepare analogous phenylimido complexes from [Re(NPh)Cl3(PPh3)2] and 1,3‐diisopropyl‐4,5‐dimethylimidazole‐2‐ylidene (Li?Pr) led to a cleavage of the rhenium‐nitrogen multiple bond and the formation of the dioxo complex [ReO2(Li?Pr)4]+. 相似文献
11.
Fawaz Aldabbagh Paul Dervan Marisa Phelan Karen Gilligan Desmond Cunningham Patrick McArdle Per B. Zetterlund Bunichiro Yamada 《Journal of polymer science. Part A, Polymer chemistry》2003,41(24):3892-3900
The 2,6‐spirodicyclohexyl substituted nitroxide, cyclohexane‐1‐spiro‐2′‐(3′,5′‐dioxo‐4′‐benzylpiperazine‐1′‐oxyl)‐6′‐spiro‐1″‐cyclohexane (BODAZ), was investigated as a mediator for controlled/living free‐radical polymerization of styrene. The values of the number‐average molecular weight increased linearly with conversion, but the polydispersities were higher than for the corresponding 2,2,6,6‐tetramethylpiperidinyl‐1‐oxy (TEMPO) and 2,5‐bis(spirocyclohexyl)‐3‐benzylimidazolidin‐4‐one‐1‐oxyl (NO88Bn) mediated systems at approximately 2.2 and 1.6 at 100 and 120 °C, respectively. These results were reflected in the rate coefficients obtained by electron spin resonance spectroscopy; at 120 °C, the values of the rate coefficients for polystyrene‐BODAZ alkoxyamine dissociation (kd), combination of BODAZ and propagating radicals (kc), and the equilibrium constant (K) were 1.60 × 10?5 s?1, 5.19 × 106 M?1 s?1, and 3.08 × 10?12 M, respectively. The value of kd was approximately one and two orders of magnitude lower, and that of K was approximately 20 and 7 times lower than for the NO88Bn and TEMPO adducts. These results are explained in terms of X‐ray crystal structures of BODAZ and NO88Bn; the six‐membered ring of BODAZ deviates significantly from planarity as compared to the planar five‐membered ring of NO88Bn and possesses a benzyl substituent oriented away from the nitroxyl group leading to a seemingly more exposed oxyl group, which resulted in a higher kc and a lower kd than NO88Bn. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3892–3900, 2003 相似文献
12.
《Magnetic resonance in chemistry : MRC》2002,40(9):614-617
[D ‐Leu1]‐microcystin‐LR is a recently discovered microcystin. We report the isolation of this microcystin analogue from a Microcystis aeruginosa strain isolated from the Lagoa de Iquipari, Rio de Janeiro, Brazil. The 1H and 13C NMR spectra were completely assigned in both MeOH‐d4 and DMSO‐d6. Further, the solution structure of this compound was investigated with the use of two‐dimensional NMR and the amide proton temperature dependence, and was compared with those of its analogs, microcystin‐RR and microcystin‐LR. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
13.
A Cyclic Methylenediphosphinic Acid: 1,3‐Dihydroxy‐1,3‐dioxo‐1,2,3,4‐tetrahydro‐1λ5,3λ5‐[1,3]diphosphinine Strong acids protonate 1,3‐bis(dimethylamino)‐1λ5,3λ5‐[1,3]diphosphinine ( 5 ) to give the corresponding cation. The protonation is followed by hydrolytic cleavage of the dimethylamino groups resulting in the formation of the cyclic methylenediphosphinic acid ( 6 ). 相似文献
14.
Ya‐Qiu Sun Prof. Dr. Dong‐Zhao Gao Yue Ma Guang‐Ming Yang Prof. Dr. Dai‐Zheng Liao Prof. Dr. Shi‐Ping Yan 《无机化学与普通化学杂志》2009,635(15):2682-2687
The two complexes of formula [Cu2(CuL)2(μ‐N3)4] · 2CH3OH ( 1 ) and [Cu2(NiL)2(μ‐N3)4] · 2CH3OH ( 2 ) (CuL and NiL, H2L = 2,3‐dioxo‐5,6,14,15‐dibenzo‐1,4,8,12‐tetraazacyclo‐pentadeca‐7,13‐dien), were synthesized and structurally determined. The magnetic susceptibility data of 1 and 2 were analyzed. For complex 1 , magnetic measurements show alternating ferromagnetic and antiferromagnetic exchange couplings J1 = 23.67 cm–1, J2 = –189.11 cm–1, zJ’ = –0.62 cm–1. For complex 2 , the doubly bridged asymmetric EO promotes a ferromagnetic interaction between CuII and CuII ions(J = 40.764 cm–1). 相似文献
15.
Heteronuclear NMR spectroscopic investigations of hydrogen bonding in 2‐(benzo[d]thiazole‐2′‐yl)‐N‐alkylanilines
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T. K. Venkatachalam G. K. Pierens P. V. Bernhardt D. C. Reutens 《Magnetic resonance in chemistry : MRC》2015,53(6):448-453
The 2‐(benzo[d]thiazole‐2′‐yl)‐N‐alkylanilines have previously revealed the presence of a strong intramolecular hydrogen bond. This in turn gives rise to a more complicated multiplet for the protons attached to the carbon adjacent to the amino group. This intramolecular hydrogen bond was investigated by a deuterium exchange experiment using heteronuclear NMR spectroscopy (1H, 13C, 15 N and 2H). We observed changes in the multiplet structure and chemical shifts providing further evidence that the deuterium replaces the hydrogen in the intramolecular hydrogen bond. A time course study of the D2O exchange confirmed the presence of a strong hydrogen bond. The comparison of the structures obtained by X‐ray crystallography showed a very small difference in planarity between the two‐substituted and four‐substituted amino compounds. In both the cases, the phenyl ring is not absolutely coplanar with the thiazole unit. The existence of this intramolecular hydrogen bond in 2‐(benzo[d]thiazole‐2′‐yl)‐N‐alkylanilines was further confirmed by single crystal X‐ray crystallography. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
16.
Proton Order–Disorder Phenomena in a Hydrogen‐Bonded Rhodium–η5‐Semiquinone Complex: A Possible Dielectric Response Mechanism
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Dr. Minoru Mitsumi Kazunari Ezaki Yuuki Komatsu Prof. Dr. Koshiro Toriumi Dr. Tatsuya Miyatou Prof. Dr. Motohiro Mizuno Nobuaki Azuma Prof. Dr. Yuji Miyazaki Prof. Dr. Motohiro Nakano Prof. Dr. Yasutaka Kitagawa Dr. Takayasu Hanashima Dr. Ryoji Kiyanagi Dr. Takashi Ohhara Prof. Dr. Kazuhiro Nakasuji 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(27):9682-9696
A newly synthesized one‐dimensional (1D) hydrogen‐bonded (H‐bonded) rhodium(II)–η5‐semiquinone complex, [Cp*Rh(η5‐p‐HSQ‐Me4)]PF6 ([ 1 ]PF6; Cp*=1,2,3,4,5‐pentamethylcyclopentadienyl; HSQ=semiquinone) exhibits a paraelectric–antiferroelectric second‐order phase transition at 237.1 K. Neutron and X‐ray crystal structure analyses reveal that the H‐bonded proton is disordered over two sites in the room‐temperature (RT) phase. The phase transition would arise from this proton disorder together with rotation or libration of the Cp* ring and PF6? ion. The relative permittivity εb′ along the H‐bonded chains reaches relatively high values (ca., 130) in the RT phase. The temperature dependence of 13C CP/MAS NMR spectra demonstrates that the proton is dynamically disordered in the RT phase and that the proton exchange has already occurred in the low‐temperature (LT) phase. Rate constants for the proton exchange are estimated to be 10?4–10?6 s in the temperature range of 240–270 K. DFT calculations predict that the protonation/deprotonation of [ 1 ]+ leads to interesting hapticity changes of the semiquinone ligand accompanied by reduction/oxidation by the π‐bonded rhodium fragment, producing the stable η6‐hydroquinone complex, [Cp*Rh3+(η6‐p‐H2Q‐Me4)]2+ ([ 2 ]2+), and η4‐benzoquinone complex, [Cp*Rh+(η4‐p‐BQ‐Me4)] ([ 3 ]), respectively. Possible mechanisms leading to the dielectric response are discussed on the basis of the migration of the protonic solitons comprising of [ 2 ]2+ and [ 3 ], which would be generated in the H‐bonded chain. 相似文献
17.
The synthesis, characterization and crystal structures of substituted imidazolate bridged binuclear copper(II) complexes, [Cu2(dien)2(L)](ClO4)3, where dien = diethylenetriamine, L = imidazolate (im—) ( 1 ), 2‐methylimidazolate (mim—) ( 2 ) and benzimidazolate (bim—) ( 3 ), are reported. The copper(II) ions of 1 — 3 posses a square planar coordination environment with dien coordinating as a tridentate ligand and the fourth position being occupied by a nitrogen atom of the bridging μ‐imidazolato group. In all three compounds the tendency to form additional long apical bonds at the copper(II) ions to the oxygen atoms of the perchlorate anions is observed. Temperature depended susceptibility data of polycrystalline samples reveal an antiferromagnetic coupling of the copper(II) atoms in 1 — 3 with J = —63.8, —75.4 and —36.8 cm—1, respectively. Significant changes for these coupling constants could not be observed for measurements on frozen aqueous solutions. ESR spectra for solids and frozen solutions are consistent with intramolecular antiferromagnetic exchange interaction between the metal ions. From the data reported it can be concluded that the predominate mechanism for transmitting exchange coupling through the imidazolate bridge is due to a σ exchange pathways. 相似文献
18.
Five new eremophilane‐type sesquiterpenes, 3β‐(acetyloxy)‐7‐hydroxynoreremophila‐6,9‐dien‐8‐one ( 1 ), 8β‐hydroxy‐2‐dehydroxyliguhodgsonal ( 2 ), 3β‐(acetyloxy)‐11‐methoxy‐8‐oxoeremophila‐6,9‐dien‐12‐oic acid ( 3 ), 3β‐(acetyloxy)‐11‐(2′‐methylbutanoyloxy)‐8‐oxoeremophila‐6,9‐dien‐12‐oic acid ( 4 ), and 3β‐(acetyloxy)‐6α‐hydroxyligularenolide ( 5 ), along with the three known compounds 6 – 8 , were isolated from the roots of Ligularia przewalskii. The structures of the new compounds were elucidated through spectral studies including HR‐EI‐MS, IR, and NMR data. 相似文献
19.
Two 3d‐4f Heterometallic Coordination Polymers of Macrocyclic Oxamide with Benzotriazole‐5‐carboxylate Co‐ligand: Syntheses,Crystal Structures and Magnetic Properties
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Two heterometallic 3d–4f coordination polymers, [Gd(CuL)2(Hbtca)(btca)(H2O)] · 2H2O ( 1 ) and [Er(CuL)2(Hbtca)(btca)(H2O)] · H2O · CH3OH ( 2 ) (CuL, H2L = 2,3‐dioxo‐5,6,14,15‐dibenzo‐1,4,8,12‐tetraazacyclo‐pentadeca‐7,13‐dien; H2btca = benzotriazole‐5‐carboxylic acid) were synthesized by solvothermal methods and characterized by single‐crystal X‐ray diffraction. Complexes 1 and 2 exhibit a double‐strand meso‐helical chain structures formed by [LnIIICuII2] (LnIII = Gd, Er) units by oxamide and benzotriazole‐5‐carboxylate bridges. They are isomorphic except that one free water molecule of 1 is replaced by a methanol molecule. All 1D chains are further interlinked by hydrogen bonds resulting in a 3D supramolecular architecture. The magnetic properties of the compound 1 and 2 are also discussed. 相似文献
20.
Gustavo Portalone Marcello Colapietro 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(3):o181-o184
A proton‐transfer compound, 1‐phenylbiguanidium 5‐nitro‐2,6‐dioxo‐1,2,3,6‐tetrahydropyrimidin‐4‐olate monohydrate, C8H12N5+·C4H2N3O5−·H2O, has been synthesized by a reaction between dilituric acid (5‐nitro‐2,4,6‐trihydroxypyrimidine, Dilit) and phenylbiguanide (N‐phenylimidocarbonimidic diamide, Big). This compound cocrystallized as a 1:1 adduct, and the asymmetric unit consists of two dilituric amino–oxo planar tautomeric anions (Dilit−), two monoprotonated phenylbiguanidium cations (BigH+) and two water molecules of crystallization (Z′ = 2). Protonation occurs at the N atom attached to the phenyl ring of Big as a result of the proton‐transfer process from the acidic hydroxy group of Dilit. In the crystal structure, the hydrated 1:1 adduct is stabilized by 25 two‐ and three‐center hydrogen bonds. 相似文献