Synthesis and Bioassay of Ethyl-2- (2-((Diethoxyphosphoryl) (Aryl) Methylamino)Thiazol-4-Yl)-2-(Methoxyimino)Acetates

Abstract

A simple, efficient, and environmentally benign methodology has been accomplished for the synthesis of α-aminophosphonates by one-pot three-component reaction of ethyl-2-amino-α-(methoxy-imino)-4-thiazoleacetate, aldehydes, and diethylphosphite by using Amberlyst-15 as catalyst at room temperature under solvent-free conditions. Their chemical structures were characterized by infrared (IR), NMR (¹H, ¹³C & ³¹P), mass spectral, and elemental analysis. All the title compounds were screened for radical-scavenging activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitic oxide (NO), and hydrogen peroxide (H₂O₂) methods.

Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.     

Synthesis of Diquinolineno[1,3,7,9]Tetraazacyclododecine-7, 15 (14H, 16H)-Dibenzene,and DNA Binding Studies of Macrocyclic Co(II), Cu(II) Complexes: As New Class of Antimicrobial Agent

The synthesis of macrocyclic ligand, diquinolineno[1,3,7,9]tetraazacyclododecine-7, 15 (14H, 16H)-dibenzene(L), is described. The metal complexes of the type [MLX₂], where (M = Co(II) (1), Cu(II) (2) and X = (Cl), have been synthesized by the reaction of ligand(L) with the corresponding metal salts, and characterized by elemental analysis, FT-IR, ¹H-NMR and electronic spectra. The binding property of the complexes with CT-DNA was studied by absorption spectra, viscosity measurements, as well as thermal denaturation studies. The absorption spectral results indicate that the complexes (1) and (2) are binds with base pairs of DNA. The intrinsic binding constant K_b had the value 3.8 × 10⁴M ^?1 for (1 Chappell, L. L., Voss, A. D. and Morrow, J. R. 1998. Inorg. Chem., 37(16): 3989–3998.  [Google Scholar]) and 3.3 × 10⁴ M^?1 for (2), respectively, in 5 mM Tris-HCl/50 mM NaCl buffer at pH 7.2. The viscosity measurement results show the viscosity of sonicated rod-like DNA fragments increased when the complex were added to the solution of calf thymus-DNA. The synthesized ligand and its metal complexes have been screened for antibacterial and antifungal activities.     

Crystallization of Pseudopolymorphs of Some Gamboge Pigments. Pyridine,Dimethylformamide and Dimethylsulfoxide Solvates of Morellic Acid,Gambogic Acid and Guttiferic Acid

Abstract

Morellic acid, gambogic acid and guttiferic acid are related naturally-occurring xanthone pigments that yield X-ray quality crystals only from solvents like pyridine, dimethylformamide (dmf) and dimethyl sulfoxide (dmso). The structures of four of these crystals have been determined and are found to contain solvents of crystallization. The solvents hydrogen bond to the carboxyl groups with O—H…O/N motifs previously seen in other carboxylic acids. Distinctive, however, is the presence of an extended though somewhat diffuse array of C—H…O hydrogen bonds that aggregates the entire solute-solvent assemblage in a multi-point manner. Pyridine and dmf are able to mimic each other with respect to their hydrogen bond donating and accepting characteristics and in this respect play equivalent roles in their solvates with morellic acid and gambogic acid. Dmso is seen to self-associate in its guttiferic acid solvate. It is possible that these solvents with multiple hydrogen bonding donor and acceptor capability can act as hydrogen bond nucleators, providing just enough rigidity to the solutes to ensure crystallization.     

Computational studies on the structures and energies of the tautomers of 1-amino-3-nitrotriazol-5-one-2-oxide

Molecular orbital calculations at the DFT-B3LYP/aug-cc-pVDZ level were performed for the possible tautomers of 1-amino-3-nitro-1,2,4-triazol-5-one-2-oxide. We have examined the substitution effects of amino and nitro groups by comparing calculated geometries, relative energies, and electrostatic potentials of model molecules. The optimized structures, vibrational frequencies, and thermodynamic values for triazol-5-one-N-oxides were obtained in their ground state. The results show 1H, 4H tautomers to be most stable. Detonation velocity and detonation pressure were evaluated by the Kamlet and Jacob equations based on the predicted density and the calculated heat of explosion. Explosive properties appear to be promising compared with those of 1,3,5-trinitro-1,3,5-triazine (D = 8.75 km/s, P = 34.7 Gpa) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (D = 8.96 km/s, P = 35.96 Gpa), 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (D = 9.20 km/s, P = 42.0 Gpa) and octanitrocubane (D = 9.90 km/s, P = 48.45 GPa). The designed triazol-5-one-N-oxides satisfy the criteria of high energy density materials.     

Oxidation of Chromanones and 2-Spirochromanones with [Hydroxy(tosyloxy)iodo]benzene in Acetonitrile Under Reflux as well as Ultrasound: A Convenient Route for the Synthesis of Chromones,Tetrahydroxanthones, and Their Higher Homologues

Oxidation of chromanones (1a-i) and 2-spiro-chromanones (j-m) using [hydroxy(tosyloxy)iodo] benzene in refluxing acetonitrile as well as using ultrasound via dehydrogenation and 2,3-alkyl migration provides a convenient route for the synthesis of chromones (2a-i), tetrahydroxanthones (2j,k) and their higher homologues (21,m). The ultrasound also enhances substantially the rate of above transformations.     

Simple Synthesis of Pyrroles Under Solvent-Free Conditions

Paal–Knorr condensation of 2,5-hexadione with primary amines in the presence of a catalytic amount of praseodymium(III) trifluoromethanesulfonate under solvent-free conditions has been accomplished with an excellent yield. This method is a very easy, rapid, and high-yielding reaction for the synthesis of N-substituted pyrrole derivatives.     

A Conventient Synthesis of 3-Hydroxy-4-chromanone Using Iodobenzene Diacetate

A useful synthesis of 3-hydroxy-4-chromanone (6) is not currently available. Lead tetraacetate oxidation of 4-chromanone (4) yields the C(3) acetoxy derivative but this compound could not be deacetylated to 6.¹ Recently Donnelly and Maloney reported² that the Algar-Flynn-Oyamada reaction (H₂O₂/CH₃OH/NaOH), which is commonly used for the conversion of o-hydroxychalcones (1) into 3-hydroxyflavanone (2) and 3-hydroxyflavones (3), does not yield 6 when applied to o-hydroxya-crylophenone 1 (R = H). The authors found that under less basic conditions using K₂CO₃ some 6 is formed but the major product is catechol. These observations clearly indicate the necessity of developing a method for making 6. The present note describes a staightforward way of preparing 3-hydroxy-4-chromanone (6) in good yield.     

Copper(II) Bromide–Catalyzed C-C/C-N Bond-Forming Reactions: Synthesis of Pyrrole-Incorporated Triarylmethanes

We have achieved a facile copper(II) bromide–catalyzed synthesis of 2,3,4-trisubtitued pyrrole incorporated into unsymmetrical triarylmethanes through direct replacement of hydroxyl group in the pyrrolyl phenyl methanol with electron-rich aromatic and heteroaromatic compounds. The newly developed method has been applied to a facile synthesis of a C2 symmetric bis-triarylmethane in which the two triarylmethanes were bridged through piperzine. The copper(II) bromide catalysis led to C-C bond formation at the C(5) position when the reacting partner was imidazole. In contrast, C-N bond formation took place with benzimdazole or 2-methylbenzimidazole.     

Realization of vibronic entanglement in terms of tunneling current in an artificial molecule

Based on the concept of molecular nonadiabatic processes, namely, curve crossing and electronic interstate coupling, here we have introduced a model of an artificial molecule composed of three coupled quantum dots in terms of displaced harmonic oscillators of the confinement potential. We have shown that the static and dynamic features of vibronic entanglement can be realized in terms of the tunneling current in our model. An entanglement sudden-death can be shown to be equivalent to the suppression of tunneling current at the appropriate parameters of the magnetic field. We have also provided the nonclassicality of the vibration of the dot confinement potential which maximizes at the anticrossing zone.     

Box–Behnken Design-Based Development and Validation of a Reverse-Phase HPLC Analytical Method for the Estimation of Paclitaxel in Cationic Liposomes

Chromatographia - Stability-indicating reverse-phase HPLC analytical method for the quantification of Paclitaxel (PTX) in the bulk and cationic liposomes was developed. The optimized method was...