Stereoselective Synthesis of Alkyl Z -2-(2-Amino-4-oxo-1,3-thiazol-5(4 H )-yliden)Acetates in Solventless Conditions

Tiourea reacts with dialkyl acetylenedicarboxylates in solventless conditions to form 1:1 adducts, which undergo a cyclization reaction to produce alkyl Z-2-(2-amino-4-oxo-1,3-thiazol-5(4H)-yliden)acetates in fairly good yields. The stereochemistry of the ethyl Z-2-(2-amino-4-oxo-1,3-thiazol-5(4H)-yliden)acetate was established by the use of X-ray single crystal structure analysis. The reaction is completely stereoselective.     

The crystal structures ofbis-{(2-benzotrifluoride)-[(2-oxo-3H-naphth-3-ylidene)-methyl]-aminato} Copper(II) andbis-{(3-benzotrifluoride)-[(2-oxo-3H-naphth-3-ylidene)-methyl]-aminato} Copper(II)

Summary TheSchiff base ligands 3-[(2-benzotrifluoride)-2-hydroxy-3H-naphth-3-ylidene)-methyl] aldamine (1) and 3-[(3-benzotrifluoride)-2-hydroxy-3H-naphth-3-ylidene)-methyl] aldamine (2) and their corresponding Cu(II) complexes (I, II) were synthesized. The crystal structures ofbis-{(2-benzotrifluoride)-[(2-oxo-3H-naphth-3-ylidene)]-methyl]-aminato} Copper(II) (I) andbis-{(3-benzotrifluoride)-[(2-oxo-3H-naphth-3-ylidene)-methyl]-aminato} Copper(II) (II) were determined. CompoundI crystallizes in the triclinic crystal system (a=12.561(3),b=16.211(4),c=8.007(2) Å, =96.29(2), =101.42(2), =97.10(2)°, space group ,Z=2); compoundII crystallizes in the monoclinic crystal system (a=5.064(2),b=19.172(4),c=15.111(3) Å, =95.05(2)°, space group P2₁/c,Z=2). The X-ray diffraction study shows that the geometry around the metal atom is square planar for both copper complexes.

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Kristallstruktur vonbis-{(2-Benzotrifluorid)-[(2-oxo-3H-naphth-3-yliden)-methyl]-aminato}-Kupfer(II) undbis-{(3-Benzotrifluorid)-[(2-oxo-3H-naphth-3-yliden)-methyl]-aminato}-Kupfer(II)

Zusammenfassung DieSchiffschen Basen 3-[(2-Benzotrifluorid)-2-hydroxy-3H-naphth-3-yliden)-methyl]-aldamin (1) und 3-[(3-Benzotrifluorid)-2-hydroxy-3H-naphth-3-yliden)-methyl]-aldamin (2) sowie ihre entsprechenden Cu(II)-Komplexe (I,II) wurden synthetisiert und ihre Struktur im Kristall bestimmt. VerbindungI kristallisiert triklin (a=15.561(3),b=16.211(4),c=8.007(2) Å, =96.29(2), =101.42(2), =97.10(2)°, Raumgruppe ,Z=2); VerbindungII kristallisiert monoklin (a=5.064(2),b=19.172(4),c=15.111(3) Å, =95.05(2)°, Raumgruppe P2₁/c,Z=2). Aus der Röntgenstrukturanalyse ergibt sich eine quadratisch planare Geometrie der Komplexe.

     

One-Pot Stereoselective Synthesis of Alkyl Z-2-[2-Amino-4-oxo-1,3-selenazol-5(4H)-yliden] Acetates

Abstract

Selenourea reacts with dialkyl acetylenedicarboxylates in acetone to form 1:1 adducts, which undergo a cyclization reaction to produce alkyl Z-2-(2-amino-4-oxo-1,3-selenazol-5(4H)-yliden) acetates in fairly good yields. The reaction is completely stereoselective.     

Synthesis,characterization and antimicrobial activities of triorganotin(IV) complexes with azo-azomethine carboxylate ligands: crystal structure of a tributyltin(IV) and a trimethyltin(IV) complex

Triorganotin(IV) complexes with polyaromatic azo-azomethine carboxylate ligands viz. 2-{4-hydroxy-3-[(2/4-hydroxyphenylimino)methyl]phenylazo}benzoic acids [H₃L¹/H₃L²] were synthesized by reacting the ligands with either bis-tri-n-butyltin(IV) oxide (for 1 and 4) or trimethyltin(IV) chloride in presence of triethylamine (for 2 and 5) or triphenyltin(IV) hydroxide (for 3 and 6). The complexes were characterized by elemental analysis, UV, IR, NMR, and mass spectrometry. NMR spectroscopic studies of the compounds suggested that the complexes adopt four-coordinate tetrahedral geometry around tin in solution. Molecular structures of 1 and 2 were determined by single-crystal X-ray diffraction. Both complexes have distorted trigonal bipyramidal geometry around tin in the solid state. Compound 1 is a one-dimensional (1-D) double chain coordination polymer which can be described as two different 24- and 30-membered non-porous macrocyclic rings constructed from two tributyltin units and two ligand moieties. The structure of 2 comprises a discrete cyclic centrosymmetric dimer with two lattice water molecules per formula unit. In the dimer, two trimethyltin entities are bridged by two ligand moieties. The dimers are further interconnected with lattice water molecules by multiple O–H?O hydrogen bonds to form a 1-D H-bonded network. The complexes were also screened for their antimicrobial activities.     

Synthesis,characterisation and structural aspects of some symmetrical organotellurium halides based on Bis(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride

Bis(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride (2) has been synthesised in good yield by reacting 1-(2-chloroethyl)-3,5-dimethylpyrazole with in situ prepared sodium telluride, Na₂Te in an aqueous solution. A number of new organotellurium halides from bis(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride have been synthesised by using different halogenating reagents. Reaction of 2 with bromine gave bis(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride dibromide (5a) in addition to unexpected product bis(2-(4-bromo-3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride dibromide (5b). All compounds were characterized by different spectroscopic techniques viz., ¹H, ¹³C, ¹²⁵Te NMR, Mass spectroscopy, IR and CHN analysis. EDXRF studies have also been employed to confirm the identity of 5a and 5b. Thermal gravimetric analysis of bis(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride (IV) chloride (4) and bis(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)telluride (IV) iodide (5c) reveals the thermal stability of these molecules above 100°C. The X-ray studies of 5c shows trigonal bipyramidal geometry around tellurium atom and intermolecular secondary interaction viz., C-H π stacking between H23A and C22 showing a supramolecular packing between two molecules.     

Synthesis,structure and properties of three one-dimensional coordination polymers {[M(II)L(NCS)2](DMF)2} n (M(II)=cadmium(II), zinc(II), manganese(II); L=1,4-bis[2-(2-pyridyl)benzimidazolato]butane)

A tetradentate N-donor ligand 1,4-bis[2-(2-pyridyl)benzimidazolato]butane (L) was prepared for construction of a coordination framework. Three one-dimensional coordination polymers {[M(II)L(NCS)₂](DMF)₂} _n (M(II) = cadmium(II), 1, zinc(II), 2, manganese(II), 3) were obtained by reaction of metal ions and L in the presence of KSCN in DMF/water. The complexes are isostructural and consist of 1D zigzag [M(II)L(NCS)₂] _n chains and DMF molecules. Within the chains, the metal atoms are each octahedrally coordinated by four N atoms of L and two N atoms of the SCN^? anions. Complexes 1 and 2 in the solid state at room temperature exhibit intense photoluminescence at 453 and 433 nm, respectively.     

On the chemistry of pyrrole pigments,XCV: 1,4-bis-(dipyrrinone-9-ylidene)-butene-2 — A novelb-homo-verdin chromophore

Summary 1,4-bis-(Dipyrrinone-9-ylidene)-butene-2, a verdinoid system extended at C-10, was synthesized by condensing a dipyrrinone unsubstituted in position 9 with 2,5-dihydro-2,5-dimethoxyfuran or 2,5-dimethoxy-tetrahydrofuran. The chemical and spectroscopic properties of this novel chromophoric system are discussed.

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Zur Chemie von Pyrrolpigmenten, 95. Mitt.: 1,4-bis-(Dipyrrinon-9-yliden)-buten-2 — ein neuerb-homo-Verdinchromophor

Zusammenfassung 1,4-bis-(Dipyrrinon-9-yliden)-buten-2, ein verdinoides, in Position 10 extendiertes System, wurde durch Kondensation eines in Position 9 unsubstituierten Dipyrrinons mit 2,5-Dihydro-2,5-dimethoxy-furan oder 2,5-Dimethoxy-tetrahydrofuran synthetisiert. Die chemischen und spektroskopischen Eigenschaften dieses neuen chromophoren Systems werden diskutiert.

     

2-{[3-(Triethoxysilyl)propyl]amino}pyridine and Derivatives

2-{[3-(Triethoxysilyl)propyl]amino}pyridine is synthesized by condensation of [3-(triethoxysilyl)propyl]amine with 2-aminopyridine. Its peretherification with triethanolamine leads to 2-[(3-silatranylpropyl)amino]pyridine and hydrolytic copolycondensation with tetraethoxysilane to cross-linked organosilicon copolymer {SiO₂·2[O1.5Si(CH₂)₃NHC₆H₄N]} _n . The latter in the medium of hydrochloric acid behaves as an anionite in respect of anionic chlorocomplexes of gold(III), platinum(IV), palladium(II) and rhodiumIII).     

Synthesis and spectroscopic studies of diorganotin(IV) adducts based on cyclotriphosphazene scaffolds with exocyclic pyrazolyl substituents

Functionalized cyclotriphosphazenes with four pyrazolyl substituents have been employed for the synthesis of two new organotin complexes. These new compounds have been characterized by elemental analysis and IR, ¹H, ³¹P and ¹¹⁹Sn NMR spectroscopy. On the basis of these data, pyrazolylcyclotriphosphazene is bis-bidentate neutral ligand coordinating to two SnMe₂Cl₂ molecules in the resulting adducts. Coordination occurs only via the pyrazolyl nitrogens; cyclotriphosphazene ring nitrogens are not involved in coordination. The ¹¹⁹Sn NMR data are consistent with increasing of coordination number of tin(IV) in solution.     

Syntheses and crystal structures of diorganotin(IV) bis(2‐pyridinethiolato‐N‐oxide) complexes

The complexes di‐n‐butyldi(2‐pyridinethiolato‐N‐oxide)tin(IV) (1), diphenyldi(2‐pyridinethiolato‐N‐oxide)tin(IV) ( 2 ) and dibenzyldi(2‐pyridinethiolato‐N‐oxide)tin(IV) ( 3 ) are synthesized and characterized by elemental analyses, IR, ¹H, ¹³C, ¹¹⁹Sn NMR spectroscopy, and their structures are determined by X‐ray crystallography. In complex 1 the coordination geometry at tin is a skew‐trapezoidal bipyramid, with cis‐S,S and cis‐O,O atoms occupying the trapezoidal plane and two n‐butyl groups occupying the apical positions, which also exhibits strong π–π stacking interactions. In complexes 2 and 3 the geometry at tin is distorted cis‐octahedral, with cis‐O,O and cis‐C,C atoms occupying the equatorial plane and trans‐S,S atoms occupying the apical positions. Their in vitro cytotoxicity against two human tumour cell lines, MCF‐7 and WiDr is reported. The ID₅₀ values found are comparable to those found for cis‐platin, but lower than for many other diorganotin compounds. Copyright © 2003 John Wiley & Sons, Ltd.     

Antimicrobial efficiency of diorganotin(IV) bis-[3-(4-chlorophenyl)-2-methylacrylate]

Abstract

Four new diorganotin(IV) carboxylates, [n-Bu₂SnL₂] (1), [Et₂SnL₂] (2), [Me₂SnL₂] (3) and [n-Oct₂SnL₂] (4), where L?=?3-(4-chlorophenyl)-2-methylacrylate, were synthesized and characterized by elemental analysis, FT-IR, multinuclear NMR (¹H, ¹³C, and ¹¹⁹Sn) and X-ray single crystal analysis for 1. A chelating bidentate ligand and six-coordinate tin centers were confirmed in the solid state by IR for all complexes and for 1 by X-ray single crystal analysis. The NMR study has shown a decrease in the coordination number of tin in solution. The complexes were screened for their in vitro antibacterial and antifungal activities. A compromised lipo/hydrophilicity and a diffusion controlled antimicrobial activity was shown by the complexes in the order 1?>?2>3?>?4. Molecular docking studies have shown hydrogen bonding and hydrophobic interactions for 1 with the target proteins of the antimicrobial strains.     

Complexes of 1-hydroxopyridine-2-thione (LH) with Rh(III), Pd(II), Cd(II) and Hg(II): crystal structure of Pd(L)2 · CHCl3

The interactions of 1-hydroxopyridine-2-thione or 2-mercaptopyridine N-oxide (LH) with transition and d¹⁰ metal ions have been investigated. The complexes [RhL₃] and [ML₂] (M = Pd, Cd and Hg) were characterized by physicochemical and spectroscopic methods. The bis(1-oxopyridine-2-thionato)palladium(II) chloroform solvate crystallizes in space group Pna2₁ with a = 9.1569(15), b = 21.306(3), c = 8.4618(14) Â, Z = 4. The structure can be described in terms of rows of bis(2-mercaptopyridine N-oxide) palladium(II) molecules which alternate with another row of molecules at an angle of approximately 24.9°. The coordination geometry about palladium(II) is nearly square-planar.     

Coordination polymers based on building blocks of dimethyltin(IV) Chloride iso‐thiocyanate and dimethyltin(IV) di‐iso‐thiocyanate with pyrazine‐2‐carboxylate and 4, 4′‐bipyridine

The reaction of 4,4′‐bipy with dimethyltin(IV) chloride iso‐thiocyanate affords the one‐dimensional (1D) coordination polymer, [Me₂Sn(NCS)Cl·(4,4′‐bipy)]_n ( 1 ), whereas reaction of dimethyltin(IV) dichloride with sodium pyrazine‐2‐carboxylate in the presence of potassium iso‐thiocyanate affords the two‐dimensional (2D) coordination polymer, {[Me₂Sn(C₄H₃N₂COO)₂]₂ [Me₂Sn(NCS)₂]}_n ( 2 ). Both coordination polymers were characterized by elemental analysis and infrared spectroscopy in addition to ¹H and ¹³C NMR spectroscopy of the soluble coordination polymer ( 1 ). A single‐crystal structure determination showed that the asymmetric unit in 1 contains Me₂Sn(NCS)Cl and 4,4′‐bipy moieties and a 1D infinite rigid chain structure forms through bridging of the 4,4′‐bipy ligand between tin atoms and the geometry around the tin atom is a distorted octahedral. Coordination polymer 2 contains two distinct tin atom geometrics in which one tin atom is seven coordinate, and the other is six coordinate. The two tin atom environments are best described as a pentagonal bipyramidal in the former and distorted octahedral in the latter where the carboxylate groups bridge the two tin atoms and construct a 2D‐coordination polymer. The ¹¹⁹Sn NMR spectroscopy indicates the octahedral geometry of 1 retains in solution. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:699–706, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/.20736     

Synthesis and characterization of the [Cu(Cin2bda)2]ClO4 and [Cu(Ncin2bda)2]ClO4 complexes: Crystal structure of [Cu(Ncin2bda)2]ClO4

Two copper(I) complexes [Cu(Cin₂bda)₂]ClO₄ (I) and [Cu(Ncin₂bda)₂]ClO₄ (II) have been prepared by the reaction of the ligands N²,N²′-bis(3-phenylallylidene)biphenyl-2,2′-diamine (L¹) and N²,N²′-bis[3-(2-nitrophenyl)allylidene]biphenyl-2,2′-diamine (L²) and copper(I) salt. These compounds were characterized by CHN analyses, ¹H NMR, IR, and UV-Vis spectroscopy. The C=N stretching frequency in the copper(I) complexes shows a shift to a lower frequency relative to the free ligand due to the coordination of the nitrogen atoms. The crystal and molecular structure of II was determined by X-ray single-crystal crystallography. The coordination polyhedron about the copper(I) center in the complex is best described as a distorted tetrahedron. A quasireversible redox behavior was observed for complexes I and II. The article is published in the original.     

Methyl and Phenylmethyl 2-Acetyl-3-{[2-(dimethylamino)-1-(methoxycarbonyl)ethenyl]amino}prop-2-enoate in the Synthesis of heterocyclic systems: Preparation of 3-amino-4H-pyrido-[1,2-a]pyrimidin-4-ones

Methyl 2-acetyl-3-{[2-(dimethylamino)-1-(methoxycarbonyl)ethenyl]amino}prop-2-enoate ( 4 ) and phenyl-methyl 2-acetyl-3-{[2-(dimethylamino)-1(methoxycarbonyl)ethenyl]amino}prop-2-enoate ( 5 ) were prepared in three steps from the corresponding acetoacetic esters, and used as reagents for the preparation of N³-protected 3-amino-4H-pyrido[1,2-a]pyrimidin-4-ones 10 – 12 , 5H-thiazolo[3,2-a]pyrimidin-5-one 13 , 4H-pyrido[1,2-a]-pyridin-4-one 19 and 2H-1-benzopyran-2-ones 20 – 23 . Free 3-amino-4H-pyrido[1,2-a]pyrimidin-4-ones 24 – 26 were prepared from 10 – 12 by removal of the 2-(methoxycarbonyl)-3-oxobut-1-enyl or 3-oxo-2-[(phenyl-methoxy)carbonyl]but-1-envl as N-protecting group by various methods.     

Green synthesis of 1,3,4-oxadiazole derivatives based on N-arylidene-2-(1-oxo-4-(4-phenoxyphenyl)phthalazin-2(1H)-yl)acetohydrazide as potential antitumor agents

Design of a new series of 1,3,4-oxadiazole derivatives was achieved in good yield via treatment of N-arylidene-2-(1-oxo-4-(4-phenoxyphenyl)phthalazin-2(1H)-yl)acetohydrazide with cerium (IV) ammonium nitrate as a catalyst. They can be formulated also using one-pot reaction of 2-(1-oxo-4-(4-phenoxyphenyl)phthalazin-2(1H)-yl)acetohydrazide, aromatic aldehyde and cerium (IV) ammonium nitrate in dichloromethane. The structural formulas of all synthesized products were elucidated based on their elemental and spectral analyses. In addition, MTT assay was used to evaluate antitumor activity of the synthesized molecules and some of them showed potent activity in comparison with Doxorubicin as a standard drug.     

Synthetic approaches towards bisspiro[naphthalene-2(1H),3′-(3H)pyrazol]-1-one-containing compounds

1,3-Dipolar cycloaddition reaction of bis{[4-(3,4-dihydro-(2H)-naphthalen-1-oxo-2-yl)methyl-idenephenyl]oxy}alkanes with nitrilimines (generated in situ by triethylamine dehydrohalogenation of the corresponding hydrazonoyl chlorides) in refluxing dry benzene afforded a mixture of monocycloadduct and dicycloadduct products in high regioselectivity. On the other hand, reaction of bis{[2-(3,4-dihydro-(2H)-naphthalen-1-oxo-2-yl)methylidenephenyl]oxy}alkanes with nitrilimines gave the corresponding dicycloadducts as the only isolable regioisomers.     

PHOSPHONOMETHYLATION OF AMINOALKANOLS PREPARATION OF 4-(PHOSPHONOMETHYL)-2-HYDROXY-2-OXO-1,4,2-OXAZAPHOSPHORINANES1

Abstract

Treatment of aminoalkanols 1 with phosphorous acid and formaldehyde in presence of conc. hydrochloric acid gave mixtures of [(2-hydroxy alkyl)imino] dimethylene diphosphonic acids 3 and 4-(phosphonomethyl)-2-hydroxy-2-oxo-1,4,2-oxazaphosphorinanes 2 from which 2 were isolated as crystalline solids. Similar treatment of 2-amino-2-methyl-1,3-propanediol 8 gave a complex mixture from which dimethylene diphosphonic acid of 5-amino-5-methyl-1,3-dioxane 9 was isolated. 2-Aminoethanethiol, when subjected to phosphonomethylation. gave an unexpected novel quarternary nitrogen product 11. N-Alkylaminoalkanols 4 on phosphonomethylation gave 3:1 mixtures of [N-alkyl-N-(2-hydroxyalkyl)amino] methane phosphonic acid 6 and N-alkyl-2-hydroxy-2-oxo-1,4,2-oxazaphosphorinane 5. Treatment of the crude mixtures of 5 and 6 with aqueous sodium hydroxide gave disodium salts of [N-alkyl-N-(2-hydroxyalkyl)amino] methanephosphonic acid 7. The ratio of the cyclic to the open chain structures obtained as well as the formation of any unexpected novel products is dependent on the structure of the aminoalkanol that is phosphonomethylated. The ¹H, ¹³C and ³¹P spectra are reported for all new compounds.     

N -oxide bridged manganese(II) coordination polymers

A simple method for synthesis of manganese(II) coordination polymers with different benzoate ligands and pyridine N-oxide having general composition [Mn(RC₆H₄CO₂)₂(PyO)] _n is presented (where PyO = pyridine N-oxide and R = H, 1a; R = 4-NO₂, 1b; R = 4-Cl, 1c; R = 4-OH, 1d; R = 2-NO₂, 1e). All these polymers are characterized by X-ray crystallography and other spectroscopic techniques. The coordination polymers have similar structures, but the positions of the manganese atoms differ. For example, 1c is highly symmetric and a mirror plane exists between each manganese site (2/m). In 1d, the manganese centers are related by an inversion center (?1) whereas in 1e the manganese centers are related by C₁ rotation (1). Reaction of manganese(II) acetate tetrahydrate with 4-chlorobenzoic acid and PyO upon crystallization from methanol/pyridine gave crystals of coordination polymer 1c along with aqua-bis-pyridine bis-4-chlorobenzoato manganese(II) (2). The structure of 2 also determined by single-crystal X-ray diffraction has a 1-D hydrogen bonded chain structure. Temperature-dependent zero-field cooled and field-cooled magnetization data of 1a–1c measured at 20 Oe and 1000 Oe show field-dependent magnetization spread over a wide temperature range from 5 to 300 K. These coordination polymers show anti-ferromagnetic behavior below 20 K.