Synthesis of new metal-free 1,2,4,5,9,10,12,13-octaaza[16]annulene derivatives using the reaction of vinamidinium salts with thiocarbohydrazide

A new series of marcocyclic ligands, 1,2,4,5,9,10,12,13-octaaza[16]annulene derivatives were synthesized by using the condensation reaction of the correspondingly [2+2] 2-heteroaryl-substituted vinamidinium salts or phenyl vinamidinium salts and derivatives or halo-substituted vinamidinum salt [1A-10A] with thiocarbohydrazide in ethanolic medium under mild condition. Metal complexes were formed by reacting of ethanolic solution of Co, Ni, and Zn with macrocyclic ligand in ethanolic medium under mild condition. Purposed complexes have been characterized with the help of elemental analyses, comparative absorption band of ν(C=N), mass, and NMR. Geometry and complex formulation are out of scope of this work. The biological activities of carohydrazide and thiocarbohydrazide base of the ligands and purposed complexes such as antimicrobial, antitumor, and insecticides have attracted significant attention in bioorganic chemistry.     

Synthesis of fluorinated allylic amines: Reaction of 2-(trimethylsilyl)ethyl sulfones and sulfoxides with fluorinated imines

A new synthesis of fluorinated allylamines through the reaction of 2-(trimethylsilyl)ethyl sulfones and sulfoxides (as vinyl anion equivalents) with imines and imino esters has been described. The process includes a TBAF-mediated fragmentation of 2-(trimethylsilyl)ethyl sulfones to afford the desired allylic amines. When the reaction is performed with the corresponding sulfoxides, the fragmentation takes place under the addition conditions, affording the final products in a single step.     

Synthesis of dihydrofurans containing trifluoromethyl ketone and heterocycles by radical cyclization of fluorinated 1,3-dicarbonyl compounds with 2-thienyl and 2-furyl substituted alkenes

Manganese(III) acetate based radical cyclization of various fluorinated 1,3-dicarbonyl compounds with 2-thienyl and 2-furyl substituted alkenes produced 3-trifluoroacetyl and 2-trifluoromethyl-dihydrofurans in good yields. The radical cyclizations of 2-methyl-5-[(E)-2-phenylvinyl]furan 2b and 2-[(E)-2-phenylvinyl]thiophene 2c led to the formations of 5-(5-methyl-2-furyl)-4,5-dihydrofuran and 5-(2-thienyl)-4,5-dihydrofuran, respectively. In the reactions of 1,3-dicarbonyls with alkenes, 2-thienyl substituted alkenes formed 4,5-dihydrofurans in higher yields than 2-furyl substituted alkenes.     

Nickel(II)-catalyzed carbon-carbon bond formation reaction of functionalized organozinc reagents with aromatic aldehydes

In the presence of a silylating reagent and catalytic amount of Ni(acac)₂, organozinc halides reacted with aromatic aldehydes to give the corresponding dialkylation products in good to excellent yields under mild conditions.     

Synthesis of monofluorinated indolizines and their derivatives by the 1,3-dipolar reaction of N-ylides with fluorinated vinyl tosylates

Monofluorinated indolizines 4, benzo[d]indolizines 7 and 4H-pyrrolo[1,2-a]benzimidazoles 8 were synthesized in moderate yields by 1,3-dipolar reaction between fluorinated vinyl tosylates 2a and N-ylides of pyridinium, isoquinolinium and benzimidazolinium, generated in situ from their halides salts. When the same N-ylides were allowed to react with 2,3,3-trifluoro-1-propenyl tosylate 2b, the unexpected product formylated indolizines and their derivatives 9 were obtained. The reaction mechanism is also proposed.     

Stereoselective synthesis of (Z)-β-fluoro-α,β-unsaturated esters from (Z)-2-fluoro-1-alkenyliodonium salts

(Z)-β-Fluoro-α,β-unsaturated esters were stereoselectively synthesized from (Z)-2-fluoro-1-alkenyliodonium salts by the Pd-catalyzed methoxycarbonylation reaction. The reaction proceeded at room temperature and various functional groups on the substrate can tolerate the reaction conditions.     

Synthesis of novel ferrocene-containing 1,3-thiazinan-2-imines: One-pot reaction promoted by ultrasound irradiation

A simple one-pot synthesis of new ferrocene-containing 1,3-thiazinan-2-imines from 3-arylamino-1-ferrocenylpropan-1-ols and phenyl isothiocyanate has been developed. The key intermediate β-hydroxy thioureas were generated in situ using ultrasound irradiation and subsequent cyclization was achieved by the addition of acetic acid. The scope of the reaction towards various 3-arylamino-1-ferrocenylpropan-1-ols has been explored and the corresponding 3-aryl-6-ferrocenyl-N-phenyl-1,3-thiazinan-2-imines were obtained in moderate to high yields (52–90%).     

Synthesis of 2-Aryl and 2-Hetaryl Derivatives of 2'-Aminospiro[(1,3-dioxane)-5,5'-thiazolin]-4'-one and Spiro[(1,3-dioxane)-5,5'-thiazolidine]2',4'-dione

2-(Het)aryl derivatives of 2'-aminospiro[(1,3-dioxane)-5,5'-thiazolin]-4'-one or spiro[(1,3-dioxane)-5,5'-thiazolidine]-2',4'-dione are formed by the acid catalyzed interaction of 2-amino-5,5-bis(hydroxymethyl)-4-thiazolinone or its oxo analog 5,5-bis(hydroxymethyl)thiazolidine-2,4-dione with (hetero)aromatic aldehydes.     

Reactions of 4-ethoxy-l,l,l-trifluoro-3-buten-2-one with phosphorous nucleophiles: Diethyl phosphite, tributyl phosphine and tris(diethylamino) phosphine

The reaction of (E)-4-ethoxy-l,l,l-trifluoro-3-buten-2-one EtOCHCHCOCF₃1 with diethyl phosphite (EtO)₂P(O)H 2 afforded a 1:1 cis- and trans-mixture of diethyl(l-trifluomethyl-3-ethoxy)allyl-phosphate EtO-CHCH-CH(CF₃)OP(O)(OEt)₂3 via the 1,2-λ⁵-oxaphosphol-4-ene intermediate. While tributyl phosphine Bu₃P added to 1 giving the double addition product Bu₃P⁺CH₂-C⁻(COCF₃)-CHCH-COCF₃5. Its resonance structure was fully identified by spectral methods and single crystal X-ray diffraction analysis. More strong phosphorous nucleophile tris(diethylamino) phosphine (Et₂N)₃P reacted with 1 to give the known compound (E)-4-(diethylamino)-l,l,l-trifluoro-3-buten-2-one Et₂N-CHCH-COCF₃10 in good yield.     

Synthesis of tripeptides containing a very crowded α,α-disubstituted glycine with pyridine rings by solid-phase Ugi reaction

Tripeptides containing a novel α,α-disubstituted glycine with two pyridine rings, α,α-di(2-pyridyl)glycine (2Dpy), were synthesized by the solid-phase Ugi reaction using di(2-pyridyl)methanimine attached directly to a Rink amide resin. Thereby, yields of the tripeptides, Z-AA₁-2Dpy-AA₃-OMe (AA₁ and AA₃ = Gly or Aib), were markedly improved, compared with yields by the solution method.     

5-(5-氟-2-吡啶偶氮)-2,4-二氨基甲苯与钴显色反应的研究及应用

研究了新合成试剂5-(5-氟-2-吡啶偶氮)-2,4-二氨基甲苯(5-F-PADAT)与钴(Ⅱ)的显色反应。实验表明,在pH4.7~9.0范围内,钴与试剂形成紫红色配合物,其最大吸收波长位于506 nm。该配合物在无机酸作用下,可转化为另一具有较高吸收特性的质子化型体,最大吸收波长红移到565 nm,适宜的酸浓度范围分别为:0.24~3.6 mol/L HClO4、0.16~3.84 mol/L H2SO4、0.48~2.4 mol/L HCl、0.64~3.84 mol/L H3PO4。配合物表观摩尔吸光系数ε565=9.1×104L.mol-1.cm-1,钴(Ⅱ)质量浓度在0~0.5μg/mL内符合比尔定律。所拟方法已应用于维生素B12针剂中微量钴的测定。     

Synthesis and properties of (E)-1,2-difluoroethylene derivatives: improvement of the ultraviolet light stability

The synthesis and properties of (E)-α,β-difluorostilbene derivatives were studied. In particular, we investigated three suppression methods of (E)–(Z) isomerisation by shortening the molecular conjugation length, which included the introduction of a fluorine atom into the ortho or para position of the benzene ring or the replacement of the benzene ring with a cyclohexane ring. The relationship between the molecular structure of liquid crystals and the level of isomerisation by ultraviolet (UV) light was discussed.     

Synthesis and anticonvulsant activity of new fluorinated N-phenyl- and N-benzyl-2-azaspiro[4.4]nonane- and [4.5]decane-1,3-dione derivatives: Part III

A series of N-phenyl- and N-benzyl-2-azaspiro[4.4]nonane- and [4.5]decane-1,3-diones containing a fluoro or trifluoromethyl substituents at the aryl ring was synthesized and tested for their anticonvulsant activity in the maximal electroshock (MES) and subcutaneous metrazole (sc.Met) tests. Among them, the most active were N-benzyl derivatives with fluoro and trifluoromethyl substituents especially at position-2 of the aryl moiety. The introduction of the phenyl ring at the imide nitrogen atom resulted in less active compounds. The results obtained showed that incorporation of fluoro or trifluoromethyl substituents increased the anticonvulsant activity in comparison to respective chloro, methoxy or methyl analogues. Crystallographically obtained conformation for one active and two inactive derivatives with trifluoromethyl substituents at position-2 or -3 of phenyl ring were initially used for molecular electrostatic potentials (MEP) calculation. The MEP distribution at carbonyl oxygen atoms was different for active and inactive molecules.     

Achieving strictly linear polyethylenes by the NNN-Fe precatalysts finely tuned with different sizes of ortho-cycloalkyl substituents

Six examples of newly synthesized α,α’-bis (aryl)-2,3:5,6-bis (pentame thylene)pyridyliron complexes [2,3:5,6-{C₄H₈C(NAr)}₂C₅HN]FeCl₂ (Ar = 2-(c-C₅H₉)-6-MeC₆H₃ Fe1 , 2-(c-C₆H₁₁)-6-MeC₆H₃ Fe2 , 2-(c-C₈H₁₅)-6-MeC₆H₃ Fe3 , 2-(c-C₅H₉)-4,6-Me₂C₆H₂ Fe4 , 2-(c-C₆H₁₁)-4,6-Me₂C₆H₂ Fe5 , 2-(c-C₈H₁₅)-4,6-Me₂C₆H₂ Fe6 ; c refers as cyclic), on activation with methylalumoxane (MAO) or modified MAO (MMAO), exhibit high activities towards ethylene polymerization, producing strictly linear polyethylenes with terminal vinyl groups. The catalytic performances are systematically investigated along with various polymerization parameters as well as the microstructures of resultant polyethylenes. The steric hindrances of ortho-cycloalkyl substituents of N_imino-aryl groups significantly affect the activities of the corresponding iron precatalysts as well as the microstructures of resultant polyethylenes: higher steric hindrance the ortho-cycloalkyl substituents, higher activity the iron precatalyst, lower molecular weight the resultant polyethylenes. Experimental observations are additionally supported by the computational study. The resultant polyethylenes exhibited excellent hydrophobicity.     

CAN-catalyzed microwave promoted reaction of indole with Betti bases under solvent-free condition and evaluation of antibacterial activity of the products

CAN-catalyzed reaction of Betti bases with indoles under microwave irradiation gives 3-(α,α-diarylmethyl)indoles. Better yield of the products, especially when one of the aryl ring is phenol were achieved. The reaction is performed in solvent-free condition. The antibacterial studies of the synthesized compounds were performed and some of the compounds showed good activity against Methicillin-resistant Staphylococcus aureus bacteria.     

Structural diversification of the coordination mode of divalent metals with 1,3-propanediaminetetraacetate (1,3-pdta): The missing crystal structure of the s-block metal complex [Sr2(1,3-pdta)(H2O)6]·H2O

This paper reports the synthesis and X-ray characteristics of the missing homonuclear s-block metal complex {[Sr₂(1,3-pdta)(H₂O)₆]·H₂O}_n. In the title compound, the hexadentate 1,3-propanediaminetetraacetate (1,3-pdta) ligand joins to two Sr(II) centers via the diamine chain. Moreover, each Sr(II) is bridged through two carboxylate O atoms and a water molecule to two neighboring Sr(II) ions. The coordination sphere around each Sr(II) ion consists of one diamine nitrogen, four carboxylate oxygens and four water molecules. Comparison with the previously reported M(II)-1,3-pdta complexes reveals that increasing of the ion size results in the incorporation of water molecules into its first coordination sphere and consequent increase of the coordination number (C.N.) from six to seven or eight, while keeping the hexadentate coordination mode of the ligand. Further increase of the metal ion size leads to the loss of the chelating properties of the diamine and formation of a bis-tridentate complex. Associated with it is the change in the binding mode of the carboxylate groups. This forms the basis for classification of divalent metal 1,3-pdta complexes into five distinct structural classes. Additionally, in the present study X-ray powder diffraction and IR spectroscopy were used to distinguish the different structural types of M(II)-1,3-pdta complexes, including Ba[Ba(1,3-pdta)]·2H₂O which has been used for their preparation.     

A new application of (polyfluoroorgano)trifluoroborate salts: the palladium-catalysed cross-coupling reaction with substituted benzenediazonium tetrafluoroborates

For the first time (polyfluoroorgano)trifluoroborate salts, namely K[C₆F₅BF₃], K[C₆HF₄BF₃] (all three isomers), K[3,4,5-C₆H₂F₃BF₃], and K[CF₂CFBF₃] were principally applied as reagents to Pd-catalysed cross-coupling reactions. A series of polyfluorinated biphenyls C₆H_5−nF_n-C₆H₄X-4′ were obtained from K[C₆H_5−nF_nBF₃] and the substrates [4-XC₆H₄N₂][BF₄] in the presence of Pd catalysts. The influence of the number and the position of the fluorine atoms in the (polyfluorophenyl)trifluoroborate salts on the reactivity in the coupling reaction was elucidated. In addition to (polyfluorophenyl)trifluoroborate salts, the cross-coupling was expanded to a first example of a perfluoroalkenyl reagent. K[CF₂CFBF₃] reacted with [4-FC₆H₄N₂][BF₄] and formed CF₂CF-C₆H₄F-4.     

Terpenoids from the barks of Magnolia maudiae (Dunn) Figlar

A new germacrenolide (1) and fourteen known terpenoids (2–15) were isolated from the barks of Magnolia maudiae (Dunn) Figlar (Magnoliaceae). The structure of (7αH,11βH)-2α,8α-dihydroxy-4α,5β-epoxy-germacr-1(10)-en-6α,12-olide (1) was elucidated by physical and spectroscopic data analysis, including 1D, 2D NMR and HR-ESI-MS. Lyratol F (9) was isolated from Magnolia for the first time. The structures of known compounds were established by comparing their spectroscopic data with those in literatures.     

4-(5-硝基-2-吡啶偶氮)-1,3-二氨基苯与铑(Ⅲ)显色反应的研究及其应用

研究了新合成试剂4-(5-硝基-2-吡啶偶氮)-1,3-二氨基苯(5-NO2-PADAB)与铑(Ⅲ)的显色反应.结果表明,在pH 3.3～4.7的乙酸-乙酸钠缓冲介质中,5-NO2-PADAB与铑形成2∶1的紫红色络合物,其最大吸收波长位于524 nm.该络合物在1.2 mol/L HClO4介质中可质子化转变为另一种型体的紫蓝络合物,最大吸收波长红移至580 nm,其表观摩尔吸光系数提高至1.52×105 L·mol-1·cm-1,以EDTA为掩蔽剂,大量常见金属离子不干扰测定.铑含量在0～0.8 μg/mL内符合比尔定律.所拟方法可应用于催化剂中微量铑的测定.