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1.
The total synthesis of Δ12‐prostaglandin J312‐PGJ3, 1 ), a reported leukemia stem cell ablator, through a number of strategies and tactics is described. The signature cross‐conjugated dienone structural motif of 1 was forged by an aldol reaction/dehydration sequence from key building blocks enone 13 and aldehyde 14 , whose lone stereocenters were generated by an asymmetric Tsuji–Trost reaction and an asymmetric Mukaiyama aldol reaction, respectively. During this program, a substituent‐governed regioselectivity pattern for the Rh‐catalyzed C?H functionalization of cyclopentenes and related olefins was discovered. The evolution of the synthesis of 1 from the original strategy to the final streamlined process proceeded through improvements in the construction of both fragments 13 and 14 , exploration of the chemistry of the hitherto underutilized chiral lactone synthon 57 , and a diastereoselective alkylation of a cyclopentenone intermediate. The described chemistry sets the stage for large‐scale production of Δ12‐PGJ3 and designed analogues for further biological and pharmacological studies.  相似文献   

2.
Some 1,1′‐ethenedithiolato complexes of nickel(II), palladium(II), and platinum(II) with different phosphine ligands, such as PPh3, PEt3, and dppe were prepared. Starting from 2‐, 3‐ as well as 4‐pyridyl methyl ketone, the complexes 1–15 were obtained in an one‐pot synthesis through reaction with carbon disulfide, using potassium‐tert‐butylate as a base. They were characterized by 1H, 13C, and 31P NMR, mass spectra, infrared spectra, and UV–VIS spectra. The molecular structures of the (Ph3P)2PdII complex 9 containing the 3‐pyridyl‐ethenedithiolato ligand and of the (Et3P)2PtII complex 12 containing the 4‐pyridyl‐ethenedithiolato ligand were determined. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:369–378, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20103  相似文献   

3.
A convenient three‐step procedure for the synthesis of three types of 3‐aryl‐2‐sulfanylthienopyridines 4, 8 , and 12 has been developed. The first step of the synthesis of thieno[2,3‐b]pyridine derivatives 4 is the replacement of the halo with a (sulfanylmethyl)sulfanyl group in aryl(2‐halopyridin‐3‐yl)methanones 1 by successive treatment with Na2S?9 H2O and chloromethyl sulfides to give aryl{2‐[(sulfanylmethyl)sulfanyl]pyridin‐3‐yl}methanones 2 . In the second step, these were treated with LDA (LiNiPr2) to give 3‐aryl‐2,3‐dihydro‐2‐sulfanylthieno[2,3‐b]pyridin‐3‐ols 3 , which were dehydrated in the last step with SOCl2 in the presence of pyridine to give the desired products. Similarly, thieno[2,3‐c]pyridine and thieno[3,2‐c]pyridine derivatives, 8 and 12 , respectively, can be prepared from aryl(3‐chloropyridin‐4‐yl)methanones 5 and aryl(4‐chloropyridin‐3‐yl)methanones 9 , respectively.  相似文献   

4.
A method for the synthesis of bicyclo[4.1.0]heptenes from 1,6‐enynes through Pd‐catalyzed cycloisomerization has been developed. N‐ and O‐tethered 1,6‐enynes were successfully transformed to their corresponding 3‐aza‐ and 3‐oxabicyclo[4.1.0]heptenes in reasonable‐to‐high yields using the catalysts [PdCl2(CH3CN)2]/P(OPh)3 or [Pd(maleimidate)2(PPh3)2] in toluene. The computational calculations using density functional theory indicate that [PdCl2{P(OPh)3}] in the oxidation state PdII acts as the active catalyst species for the formation of 3‐azabicyclo[4.1.0]heptenes through 6‐endo‐dig cyclization.  相似文献   

5.
A convergent synthesis of an analogue of (1α)‐1,25‐dihydroxyvitamin D3 ( 1b ) with a C7 side chain at C(12), i.e., of 5 (Fig.), is described. A key step of the synthesis is the assembly of the triene system by a PdII‐catalyzed ring closure of an enol triflate (‘bottom’ fragment) followed by coupling of the resulting PdII intermediate with an alkenylboronate (‘upper’ fragment) (Scheme 2). The synthetic strategy allows isotopic labelling at the end of the synthesis.  相似文献   

6.
Two different zinc sulfite compounds have been prepared through the decomposition of pyrosulfite–­di­thionite ions in aqueous solution, viz. a dimeric complex, di‐μ‐sulfito‐κ3O,O′:O′′;κ3O:O′,O′′‐bis­[(4,4′‐di­methyl‐2,2′‐bi­pyridine‐κ2N,N′)­zinc(II)] dihydrate, [Zn2(SO3)2(C12H12N2)2]·2H2O, (I), which was solved and refined from a twinned sample, and an extended polymer, poly­[[aqua(1,10‐phenanthroline‐κ2N,N′)­zinc(II)]‐μ3‐sulfito‐κ2O:O′:O′′‐zinc(II)‐μ3‐sulfito‐κ3O:O:O′], [Zn2(SO3)2(C12H10N2)(H2O)]n, (II). In (I), the dinuclear ZnII complex has a center of symmetry. The cation is five‐coordinate in a square‐pyramidal arrangement, the anion fulfilling a bridging chelating role. Compound (II) comprises two different zinc units, one being five‐coordinate (square pyramidal) and the other four‐coordinate (trigonal pyramidal), and two independent sulfite groups with different binding modes to the cationic centers.  相似文献   

7.
The structures of the anhydrous 1:1 proton‐transfer compounds of the dye precursor aniline yellow [4‐(phenyldiazenyl)aniline], namely isomeric 4‐(phenyldiazenyl)anilinium 2‐carboxy‐6‐nitrobenzoate, C12H12N3+·C8H4NO6, (I), and 4‐(phenyldiazenyl)anilinium 2‐carboxy‐4‐nitrobenzoate, C12H12N3+·C8H4NO6, (II), and 4‐(phenyldiazenyl)anilinium 3‐carboxy‐5‐nitrobenzoate monohydrate, C12H12N3+·C8H4NO6·H2O, (III), have been determined at 130 K. In (I) the cation has longitudinal rotational disorder. All three compounds have substructures comprising backbones formed through strong head‐to‐tail carboxyl–carboxylate hydrogen‐bond interactions [graph set C(7) in (I) and (II), and C(8) in (III)]. Two‐dimensional sheet structures are formed in all three compounds by the incorporation of the 4‐(phenyldiazenyl)anilinium cations into the substructures, including, in the cases of (I) and (II), infinite H—N—H to carboxylate O—C—O group interactions [graph set C(6)], and in the case of (III), bridging through the water molecule of solvation. The peripheral alternating aromatic ring residues of both cations and anions give only weakly π‐interactive step features which lie between the sheets.  相似文献   

8.
The reaction of propane‐1,3‐diamine hydrochloride, 18‐crown‐6 and zinc(II) chloride in methanol solution yields the title complex salt [systematic name: propane‐1,3‐diaminium tetrachloridozincate(II)–1,4,7,10,13,16‐hexaoxacyclooctadecane (1/1)], (C3H12N2)[ZnCl4]·C12H24O6, with an unusual supramolecular structure. The diprotonated propane‐1,3‐diaminium cation forms an unexpected 1:1 supramolecular rotator–stator complex with the crown ether, viz. [C3H12N2(18‐crown‐6)]2+, in which one of the –NH3+ substituents nests in the crown and interacts through N—H...O hydrogen bonding. The other –NH3+ group interacts with the [ZnCl4]2− anion via N—H...Cl hydrogen bonding, forming cation–crown–anion ribbons parallel to [010].  相似文献   

9.
In order to study the in vivo protective effect on myocardial ischemia, (20S ,24R )‐epoxydammarane‐12β,25‐diol, (V), and (20S ,24S )‐epoxydammarane‐12β,25‐diol, (VI), were synthesized through a novel synthetic route. Two key intermediates, namely (20S ,24R )‐3‐acetyl‐20,24‐epoxydammarane‐3β,12β,25‐triol, (III) [obtained as the hemihydrate, C32H54O5·0.5H2O, (IIIa ), and the ethanol hemisolvate, C32H54O5·0.5C2H5OH, (IIIb ), with identical conformations but different crystal packings], and (20S ,24S )‐3‐acetyl‐20,24‐epoxydammarane‐3β,12β,25‐triol, C32H54O5, (IV), were obtained during the synthesis. The structures were confirmed by 1H NMR, 13C NMR and HRMS analyses, and single‐crystal X‐ray diffraction. Molecules of (IIIa ) are extended into a two‐dimensional network constructed with water molecules linked alternately through intermolecular O—H…O hydrogen bonds, which are further stacked into a three‐dimensional network. Compound (IIIb ) contains two completely asymmetric molecules, which are linked in a disordered manner through intermolecular C—H…O hydrogen bonds. While the crystal stacks in compound (IV) are linked via weak C—H…O hydrogen bonds, the hydrogen‐bonded chains extend helically along the crystallographic b axis.  相似文献   

10.
4‐Amino‐trans‐azobenzene {or 4‐[(E)‐phenyl­diazen­yl]aniline} can form isomeric salts depending on the site of protonation. Both orange bis{4‐[(E)‐phenyl­diazen­yl]anilinium} hydrogen phos­phate, 2C12H12N3+·HPO42−, and purple 4‐[(E)‐phenyl­diazen­yl]­anilinium dihydrogen phosphate phosphoric acid solvate, C12H12N3+·H2PO4·H3PO4, (II), have layered structures formed through O—H⋯O and N—H⋯O hydrogen bonds. Additionally, azobenzene fragments in (I) are assembled through C—H⋯π inter­actions and in (II) through π–π inter­actions. Arguments for the colour difference are tentatively proposed.  相似文献   

11.
The design and synthesis of metal coordination and supramolecular frameworks containing N‐donor ligands and dicyanidoargentate units is of interest due to their potential applications in the fields of molecular magnetism, catalysis, nonlinear optics and luminescence. In the design and synthesis of extended frameworks, supramolecular interactions, such as hydrogen bonding, π–π stacking and van der Waals interactions, have been exploited for molecular recognition associated with biological activity and for the engineering of molecular solids.The title compound, [Ag(CN)(C12H12N2)]n, crystallizes with the AgI cation on a twofold axis, half a cyanide ligand disordered about a centre of inversion and half a twofold‐symmetric 5,5′‐dimethyl‐2,2′‐bipyridine (5,5′‐dmbpy) ligand in the asymmetric unit. Each AgI cation exhibits a distorted tetrahedral geometry; the coordination environment comprises one C(N) atom and one N(C) atom from substitutionally disordered cyanide bridging ligands, and two N atoms from a bidentate chelating 5,5′‐dmbpy ligand. The cyanide ligand links adjacent AgI cations to generate a one‐dimensional zigzag chain. These chains are linked together via weak nonclassical intermolecular interactions, generating a two‐dimensional supramolecular network.  相似文献   

12.
Hybrid peptides composed of α‐ and β‐amino acids have recently emerged as new class of peptide foldamers. Comparatively, γ‐ and hybrid γ‐peptides composed of γ4‐amino acids are less studied than their β‐counterparts. However, recent investigations reveal that γ4‐amino acids have a higher propensity to fold into ordered helical structures. As amino acid side‐chain functional groups play a crucial role in the biological context, the objective of this study was to investigate efficient synthesis of γ4‐residues with functional proteinogenic side‐chains and their structural analysis in hybrid‐peptide sequences. Here, the efficient and enantiopure synthesis of various N‐ and C‐terminal free‐γ4‐residues, starting from the benzyl esters (COOBzl) of N‐Cbz‐protected (E)α,β‐unsaturated γ‐amino acids through multiple hydrogenolysis and double‐bond reduction in a single‐pot catalytic hydrogenation is reported. The crystal conformations of eight unprotected γ4‐amino acids (γ4‐Val, γ4‐Leu, γ4‐Ile, γ4‐Thr(OtBu), γ4‐Tyr, γ4‐Asp(OtBu), γ4‐Glu(OtBu), and γ‐Aib) reveals that these amino acids adopted a helix favoring gauche conformations along the central Cγ? Cβ bond. To study the behavior of γ4‐residues with functional side chains in peptide sequences, two short hybrid γ‐peptides P1 (Ac‐Aib‐γ4‐Asn‐Aib‐γ4‐Leu‐Aib‐γ4‐Leu‐CONH2) and P2 (Ac‐Aib‐γ4‐Ser‐Aib‐γ4‐Val‐Aib‐γ4‐Val‐CONH2) were designed, synthesized on solid phase, and their 12‐helical conformation in single crystals were studied. Remarkably, the γ4‐Asn residue in P1 facilitates the tetrameric helical aggregations through interhelical H bonding between the side‐chain amide groups. Furthermore, the hydroxyl side‐chain of γ4‐Ser in P2 is involved in the interhelical H bonding with the backbone amide group. In addition, the analysis of 87 γ4‐residues in peptide single‐crystals reveal that the γ4‐residues in 12‐helices are more ordered as compared with the 10/12‐ and 12/14‐helices.  相似文献   

13.
Carba‐closo‐dodecaborate anions with two functional groups have been synthesized via a simple two‐step procedure starting from monoamino‐functionalized {closo‐1‐CB11} clusters. Iodination at the antipodal boron atom provided access to [1‐H2N‐12‐I‐closo‐1‐CB11H10]? ( 1 a ) and [2‐H2N‐12‐I‐closo‐1‐CB11H10]? ( 2 a ), which have been transformed into the anions [1‐H2N‐12‐RC?C‐closo‐1‐CB11H10]? (R=H ( 1 b ), Ph ( 1 c ), Et3Si ( 1 d )) and [2‐H2N‐12‐RC?C‐closo‐1‐CB11H10]? (R=H ( 2 b ), Ph ( 2 c ), Et3Si ( 2 d )) by microwave‐assisted Kumada‐type cross‐coupling reactions. The syntheses of the inner salts 1‐Me3N‐12‐RC?C‐closo‐1‐CB11H10 (R=H ( 1 e ), Et3Si ( 1 f )) and 2‐Me3N‐12‐RC?C‐closo‐1‐CB11H10 (R=H ( 2 e ), Et3Si ( 2 f )) are the first examples for a further derivatization of the new anions. All {closo‐1‐CB11} clusters have been characterized by multinuclear NMR and vibrational spectroscopy as well as by mass spectrometry. The crystal structures of Cs 1 a , [Et4N] 2 a , K 1 b , [Et4N] 1 c , [Et4N] 2 c , 1 e , and [Et4N][1‐H2N‐2‐F‐12‐I‐closo‐1‐CB11H9]?0.5 H2O ([Et4N ]4 a ?0.5 H2O) have been determined. Experimental spectroscopic data and especially spectroscopic data and bond properties derived from DFT calculations provide some information on the importance of inductive and resonance‐type effects for the transfer of electronic effects through the {closo‐1‐CB11} cage.  相似文献   

14.
A new bridging ligand, 2,3‐di(2‐pyridyl)‐5‐phenylpyrazine (dpppzH), has been synthesized. This ligand was designed so that it could bind two metals through a NN‐CNN‐type coordination mode. The reaction of dpppzH with cis‐[(bpy)2RuCl2] (bpy=2,2′‐bipyridine) affords monoruthenium complex [(bpy)2Ru(dpppzH)]2+ ( 12+ ) in 64 % yield, in which dpppzH behaves as a NN bidentate ligand. The asymmetric biruthenium complex [(bpy)2Ru(dpppz)Ru(Mebip)]3+ ( 23+ ) was prepared from complex 12+ and [(Mebip)RuCl3] (Mebip=bis(N‐methylbenzimidazolyl)pyridine), in which one hydrogen atom on the phenyl ring of dpppzH is lost and the bridging ligand binds to the second ruthenium atom in a CNN tridentate fashion. In addition, the RuPt heterobimetallic complex [(bpy)2Ru(dpppz)Pt(C?CPh)]2+ ( 42+ ) has been prepared from complex 12+ , in which the bridging ligand binds to the platinum atom through a CNN binding mode. The electronic properties of these complexes have been probed by using electrochemical and spectroscopic techniques and studied by theoretical calculations. Complex 12+ is emissive at room temperature, with an emission λmax=695 nm. No emission was detected for complex 23+ at room temperature in MeCN, whereas complex 42+ displayed an emission at about 750 nm. The emission properties of these complexes are compared to those of previously reported Ru and RuPt bimetallic complexes with a related ligand, 2,3‐di(2‐pyridyl)‐5,6‐diphenylpyrazine.  相似文献   

15.
In 3,4‐di‐2‐pyridyl‐1,2,5‐oxadiazole (dpo), C12H8N4O, each mol­ecule resides on a twofold axis and inter­acts with eight neighbours via four C—H⋯N and four C—H⋯O inter­actions to generate a three‐dimensional hydrogen‐bonded architecture. In the perchlorate analogue, 2‐[3‐(2‐pyrid­yl)‐1,2,5‐oxadiazol‐4‐yl]pyridinium perchlorate, C12H9N4O+·ClO4 or [Hdpo]ClO4, the [Hdpo]+ cation is bisected by a crystallographic mirror plane, and the additional H atom in the cation is shared by the two pyridyl N atoms to form a symmetrical intra­molecular N⋯H⋯N hydrogen bond. The cations and perchlorate anions are linked through C—H⋯O hydrogen bonds and π–π stacking inter­actions to form one‐dimensional tubes along the b‐axis direction.  相似文献   

16.
The synthesis and characterization of the unsymmetric hafnium dialkyl [1‐(η5‐9‐fluorenyl)‐2‐(η5‐1‐indenyl)ethane]HfCl2 ( 2 ) and corresponding dimethyl complex [1‐(η5‐9‐fluorenyl)‐2‐(η5‐1‐indenyl)ethane]Hf(CH3)2 ( 3 ) is described. The dialkyl hafnocene ( 3 ) crystallizes in monoclinic space group P21/c (No. 14) with a = 9.458(8), b = 8.541(8), c = 23.733(11) Å, β = 93.16(5) deg., V = 1914(3) Å3, Z = 4. Further on, complex 3 was activated with methylaluminiumoxane (MAO) and utilized as a catalyst in ethene polymerization.  相似文献   

17.
Carbon monoxide (CO) has recently been identified as a gaseous signaling molecule that exerts various salutary effects in mammalian pathophysiology. Photoactive metal carbonyl complexes (photoCORMs) are ideal exogenous candidates for more controllable and site‐specific CO delivery compared to gaseous CO. Along this line, our group has been engaged for the past few years in developing group‐7‐based photoCORMs towards the efficient eradication of various malignant cells. Moreover, several such complexes can be tracked within cancerous cells by virtue of their luminescence. The inherent luminecscent nature of some photoCORMs and the change in emission wavelength upon CO release also provide a covenient means to track the entry of the prodrug and, in some cases, both the entry and CO release from the prodrug. In continuation of the research circumscribing the development of trackable photoCORMs and also to graft such molecules covalently to conventional delivery vehicles, we report herein the synthesis and structures of three rhenium carbonyl complexes, namely, fac‐tricarbonyl[2‐(pyridin‐2‐yl)‐1,3‐benzothiazole‐κ2N ,N ′](4‐vinylpyridine‐κN )rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C12H8N2S)(CO)3](CF3SO3), ( 1 ), fac‐tricarbonyl[2‐(quinolin‐2‐yl)‐1,3‐benzothiazole‐κ2N ,N ′](4‐vinylpyridine‐κN )rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C16H10N2S)(CO)3](CF3SO3), ( 2 ), and fac‐tricarbonyl[1,10‐phenanthroline‐κ2N ,N ′](4‐vinylpyridine‐κN )rhenium(I) trifluoromethanesulfonate, [Re(C7H7N)(C12H8N2)(CO)3](CF3SO3), ( 3 ). In all three complexes, the ReI center resides in a distorted octahedral coordination environment. These complexes exhibit CO release upon exposure to low‐power UV light. The apparent CO release rates of the complexes have been measured to assess their comparative CO‐donating capacity. The three complexes are highly luminescent and this in turn provides a convenient way to track the entry of the prodrug molecules within biological targets.  相似文献   

18.
An efficient and simple method developed for the synthesis of 6‐methyl‐1,2,3,4‐tetrahydro‐N‐aryl‐2‐oxo/thio‐4‐arylpyrimidine‐5‐carboxamide derivatives ( 4a‐o ) using UO2(NO3)2.6H2O catalyst under conventional and ultrasonic conditions. The ultrasound irradiation synthesis had shown several advantages such as milder conditions, shorter reaction times and higher yields. The structures of all the newly synthesized compounds have been confirmed by FT‐IR, 1H NMR, 13C NMR and mass spectra.  相似文献   

19.
In the lattice of the title compound (systematic name: 5,6,7‐trihydroxy‐4′‐meth­oxy­isoflavone monohydrate), C16H12O6·H2O, the isoflavone mol­ecules are linked into chains through R43(17) motifs composed via O—H⋯O and C—H⋯O hydrogen bonds. Centrosymmetric R42(14) motifs assemble the chains into sheets. Hydrogen‐bonding and aromatic π–π stacking inter­actions lead to the formation of a three‐dimensional network structure.  相似文献   

20.
The isomorphous structures of the title molecules, 4‐amino‐1‐(2‐deoxy‐β‐d ‐erythro‐pento­furan­osyl)‐3‐iodo‐1H‐pyrazolo‐[3,4‐d]pyrimidine, (I), C10H12IN5O3, and 4‐amino‐3‐bromo‐1‐(2‐deoxy‐β‐d ‐erythro‐pento­furan­osyl)‐1H‐pyrazolo[3,4‐d]­pyrimidine, (II), C10H12BrN5O3, have been determined. The sugar puckering of both compounds is C1′‐endo (1′E). The N‐­glycosidic bond torsion angle χ1 is in the high‐anti range [?73.2 (4)° for (I) and ?74.1 (4)° for (II)] and the crystal structure is stabilized by hydrogen bonds.  相似文献   

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