Mixed Condensation Reactions Research Articles

CO-CYCLIZATION OF ETNCO AND ME2CO AS THE RESULTS OF THEIR SELECTIVE INSERTION INTO THE NIOBIUM-CHLORINE BOND

Development of the new methods for drug production is impossible without reliance on the novel and unorthodox approaches to the synthesis of heterocyclic complexes and compounds.The method is based on the study of new aspects of the of two types of behavior of the coordinated molecules in reaction - their ability to insert into the same transition metal-halogen bond, and their ability to form the unusual heterocyclic ligands, or even molecules after leaving the complex’s coordination sphere. This will make it possible not only to synthesize the already-known compounds under milder conditions, but to also obtain new ones as products of such mixed condensation reactions. On the one hand, this opens up new possibilities for designing and performing the intraspherical "stitching" of ligands and their synthesis with high efficiency and selectivity. 
 On the other hand, these reactions can be considered a significant contribution to the fundamental coordination chemistry in terms of illustration of the new modalities of the mutual influence of ligands, namely their ability to stimulate each other for a mutual insertion, and sheds light on the mechanisms of the intraspheric condensation. Oxadiazine derivatives, just like the derivatives of triazine we synthesized and reported previously, could become a foundation for the generation of biologically-active compounds, often containing heterocyclic fragments and frequently used for the treatment of malignant tumors. It can be expected that the developed method will find use in the synthesis of the new classes of potential antitumor compounds.
 We have previously found that organic isocyanate not only themselves insert into M-Hal bond, but can also activate the insertion of acetonitrile, the resulting heteromolecular chain of inserted molecules being composed of two MeNCO and one MeCN fragments. Such a structure of this complexes was confirmed be synthesis of striazine derivatives on their base. In this work was to determine optimum condition for the insertion of ethyl isocyanate with acetone into niobium-chlorine bond, as well as their subsequent mixed co-cyclization with obtaining of oxadiazine derivative.

CO-CYCLIZATION OF ETNCO AND ME2CO AS THE RESULTS OF THEIR SELECTIVE INSERTION INTO THE NIOBIUM-CHLORINE BOND

Development of the new methods for drug production is impossible without reliance on the novel and unorthodox approaches to the synthesis of heterocyclic complexes and compounds.The method is based on the study of new aspects of the of two types of behavior of the coordinated molecules in reaction - their ability to insert into the same transition metal-halogen bond, and their ability to form the unusual heterocyclic ligands, or even molecules after leaving the complex’s coordination sphere. This will make it possible not only to synthesize the already-known compounds under milder conditions, but to also obtain new ones as products of such mixed condensation reactions. On the one hand, this opens up new possibilities for designing and performing the intraspherical "stitching" of ligands and their synthesis with high efficiency and selectivity. 
 On the other hand, these reactions can be considered a significant contribution to the fundamental coordination chemistry in terms of illustration of the new modalities of the mutual influence of ligands, namely their ability to stimulate each other for a mutual insertion, and sheds light on the mechanisms of the intraspheric condensation. Oxadiazine derivatives, just like the derivatives of triazine we synthesized and reported previously, could become a foundation for the generation of biologically-active compounds, often containing heterocyclic fragments and frequently used for the treatment of malignant tumors. It can be expected that the developed method will find use in the synthesis of the new classes of potential antitumor compounds.
 We have previously found that organic isocyanate not only themselves insert into M-Hal bond, but can also activate the insertion of acetonitrile, the resulting heteromolecular chain of inserted molecules being composed of two MeNCO and one MeCN fragments. Such a structure of this complexes was confirmed be synthesis of striazine derivatives on their base. In this work was to determine optimum condition for the insertion of ethyl isocyanate with acetone into niobium-chlorine bond, as well as their subsequent mixed co-cyclization with obtaining of oxadiazine derivative.

Synthesis of Low-symmetry Ball-shaped Ruthenium Complexes and Fine-tuning of Their Optical Properties in the Visible and NIR Region

The synthesis of the first examples of cyano-substituted low-symmetry ball-shaped ruthenium complexes is reported. Systematic mixed condensation reactions of benzonitrile, terephthalonitrile, 1,3-d...

Synthesis, characterization, and biological evaluation of new heterocyclic systems 1, 2, 3-triazole-isoxazoline from eugenol by the mixed condensation reactions

We report the synthesis of new series of heterocyclic systems eugenol 1 derivatives by the mixed condensation reaction of 1,3-dipolar azide and the oxide of p-chlorophenylnitrile on the 4-allyl-2-methoxy-1-(prop-2-yn-1-yloxy)benzene 2. The mono and bicycloadducts, whose structure is homologous to compounds having a broad spectrum of activity, were obtained in good yields. The monocondensation reaction of azides on 4-allyl-2-methoxy-1-(prop-2-yn-1-yloxy)benzene 2 is completely chemoselective, regioselective and stereospecific. The condensation of nitrile oxide on 1,2,3-triazole monocycloadducts prepared was chemoselective and regioselective. The structure of all cycloadducts were characterized and confirmed by the 1H, 13C, 2D nuclear magnetic resonance and mass spectrometry analysis. All the newly synthesized mono and bis-heterocyclic compounds have been selected for their antiproliferative activity against HT-1080 fibrosarcoma, A549 lung carcinoma, and MCF-7 and MDA-MB-231 breast carcinoma cell lines. Among the derivatives, only the compounds 4a, 4b, 5a, 5b, 5d, 5e and 5g showed significant cytotoxicity with IC50 values ranging from 15.31 to 18.81 µM against HT-1080 cells, and 17.32 to 25.94 µM against the other cell lines.

An Investigation into Retigabine (Ezogabine) Associated Dyspigmentation in Rat Eyes by MALDI Imaging Mass Spectrometry.

Retigabine (RTG) is an antiepileptic drug approved as an adjunctive treatment for refractory partial-onset seizures in adults. In April 2013, the Food and Drug Administration issued a warning that RTG could cause changes in retinal pigmentation and discoloration of skin, resulting in a blue appearance. As part of a larger preclinical effort to gain a mechanistic understanding as to the origins of retinal pigment changes associated with RTG, we conducted a long-term repeat dosing study in rats. Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI IMS) was used to determine the distribution of RTG and its metabolites in the rat eye following 13 and 39 weeks of dosing. IMS revealed the presence of RTG, a previously characterized N-acetyl metabolite of RTG (NAMR), and several species structurally related through the dimerization of RTG and NAMR. These species were highly localized to the melanin-containing layers of the uveal tract of the rat eye including the choroid, ciliary body, and iris, suggesting that the formation of these dimers occurs from melanin bound RTG and NAMR. Furthermore, several of the RTG-related dimers have UV absorbance which give them a purple color in solution. We propose that the melanin binding of RTG and NAMR effectively concentrates the two compounds to enable mixed condensation reactions to occur when the binding provides the proper geometry in the redox environment of the uveal tissues. High lateral resolution images illustrate that the blood-retinal barrier effectively restricts retinal access to RTG-related compounds. The spatial information provided by MALDI IMS was critical in contextualizing the homogenate concentrations of key RTG-related compounds and helped provide a basis for the mechanism of dimer formation.

Mechanisms of reactions of sulfur hydride hydroxide: tautomerism, condensations, and C-sulfenylation and O-sulfenylation of 2,4-pentanedione.

The conformations, equilibrium structures, hydrogen bonds, and non-covalent interactions involved in the mechanisms of tautomerization, condensations, and C-sulfenylation and O-sulfenylation of 2,4-pentanedione by sulfur hydride hydroxide (hydrogen thioperoxide, oxadisulfane, H-SOH) have been studied using BD(T), CCSD(T), and QCISD(T) with the cc-pVTZ basis set and using B3LYP, B3PW91, CAM-B3LYP, PBE1PBE, PBEh1PBE, LC-ωPBE, M06-2X, and ωB97XD with the 6-311+G(d,p) basis set. All levels of theory predict the sulfenyl (H-SOH) tautomer of hydrogen thioperoxide to be lower in energy than the sulfinyl (H2S═O) tautomer. Four reasonable mechanisms were considered for the tautomerization of the sulfenyl tautomer of hydrogen thioperoxide to the sulfinyl tautomer: a cyclic three-membered water-free transition state (TS, CCSD(T) activation energy barrier E(⧧) = 65.1 kcal/mol), a cyclic five-membered transition state with one water molecule (TSH2O, E(⧧) = 31.1 kcal/mol), a cyclic seven-membered transition state with two water molecules (TS2H2O, E(⧧) = 14.5 kcal/mol), and a cyclic nine-membered transition state with three water molecules (TS3H2O, E(⧧) = 5.6 kcal/mol). The mechanisms involve hydrogen-bonded reactant complexes and hydrogen-bonded product complexes. The CCSD(T)-predicted energy barriers for the condensation of hydrogen thioperoxide to form thiosulfinic acid through transition states with zero, one, and two waters are E(⧧) = 42.0, 18.3, and 0 kcal/mol, respectively. Mixed condensation reactions are predicted to afford organosulfur products and compounds containing sulfur-selenium bonds. Hydrogen thioperoxide is predicted to add to 2,4-pentanedione to form C-sulfenylated (sulfide, thioether) and O-sulfenylated (sulfenate ester) products. Similar mechanistic trends and reaction pathways are observed in the tautomerism, condensations, and C-sulfenylation and O-sulfenylation reactions of hydrogen thioperoxide. The water molecules set up proton relay networks (bridges) that reduce ring strain, generate favorable conformations for reactivity, lower energy barriers, and increase the numbers of stabilizing hydrogen bonds and nonbonding interactions.

Synthesis and Electronic Properties of an Azulene-fused Tribenzotetraazaporphyrin

Abstract A novel tribenzotetraazaporphyrin with a fused azulene ring was synthesized via mixed condensation reaction of 5,6-dicyanoazulene and 3,6-dibutoxyphthalonitrile. The macrocycle exhibited several intense absorption peaks from 600 to 900 nm. The spectroscopic properties were analyzed by DFT calculations.

ChemInform Abstract: Stirring the Porphyrin Alphabet Soup — Functionalization Reactions for Porphyrins

AbstractReview: 85 refs.

Stirring the porphyrin alphabet soup—functionalization reactions for porphyrins

Advances in the synthesis of unsymmetrically meso substituted porphyrins are based on the development of new total syntheses and porphyrin functionalization methods. These methods have replaced earlier mixed condensation reactions and give synthetic access to almost any desired meso-substituted porphyrin. They include the complete series of porphyrin homologues and regioisomers of the A(x)-series with either alkyl or aryl residues, and numerous examples of ABCD-type chromophores. The syntheses are based on a combination of classic functionalization reactions, the use of organolithium reagents in S(N)Ar reactions, and organometallic reactions with Pd, Ni, Cr, Ru, B, and Sn catalysis. This feature article gives an account of our work in the past decade to develop synthetic methods for the A(x)- and ABCD-type porphyrins and their use as optical materials and photosensitizers.

Synthesis and electronic structures of D2 h-symmetry tetrabenzoporphyrins

A novel low-symmetry tetrabenzoporphine with D 2 h symmetry ( 1) and its zinc complex ( 2) were prepared via mixed condensation reaction of 5,6-dimethyl phthalimide and 4,5,6,7-tetraphenyl phthalimide with sodium acetate in the presence of zinc acetate. The zinc complex 2 exhibited a split Q band at 640 and 623 nm and a single Soret band at 435 nm. The absorption spectra of 1 and 2 were calculated and analyzed using Hartree–Fock theory based on INDO/S Hamiltonian.

Synthesis and characterization of novel azo-bridged Zn(II) and Co(II) bisphthalocyanines

Metal phthalocyanines containing an unsymmetrically substituted nitro group were synthesized from 4-nitrophthalonitrile and the corresponding anhydrous metal salts ( Co ( OAc )2, Zn ( OAc )2) by the method of statistically mixed condensation reactions. The new type of metallo-bisphthalocyanine compounds connected by a N = N bridge was prepared from the reactions of respective nitro compounds with sodium hydroxide ( NaOH ) and activated zinc powder in a mixture of methanol ( MeOH ) and tetrahydrofuran (THF). The structures of these compounds were characterized by using 1 H NMR, IR, elemental analyses, UV-vis and magnetic circular dichroism spectroscopies.

Synthesis of New Tetraheterocyclic Systems by the Mixed Condensation Reactions on [1,2,4]Triazolo[4,3‐a][1,5]benzodiazepines.

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Synthesis of New Tetraheterocyclic Systems by the Mixed Condensation Reactions on [1,2,4]Triazolo[4,3‐a][1,5]benzodiazepines

We report here a one step synthesis of a new series of bis‐[1,2,4‐triazolo][4,3‐a:3′,4′‐d][1,5]benzodiazepines 3a–e and [1,2,4]oxadiazolo[5,4‐d][1,2,4]triazolo[4,3‐a][1,5]benzodiazepines 5a–c by the condensation reactions of diarylnitrilimines and arylonitrile oxides. This 1,3‐dipolar cycloaddition is completely regioselective. The structure of these products has been confirmed by 1H, 13C NMR and mass spectroscopic.

Synthesis of New Tri- and Tetraheterocyclic Systems: 1,3-Dipolar Cycloaddition of Nitrilimines on 2,7-Dimethyl-4-Phenyl-3H-1,5-Benzodiazepine

We report here a one-step synthesis of a new series of tri and tetraheterocyclic systems by the mixed condensation reactions of N-aryl-C-ethoxycarbonylnitrilimines and diarylnitrilimines with 2,7-dimethyl-4-phenyl-3H-1,5-benzodiazepine This 1,3-dipolar cycloaddition is completely peri and regioselective The structure of these products has been confirmed by 1H, 13C NMR, mass spectroscopic and X-ray crystallographic analysis.

Selective Synthesis of Binuclear and Trinuclear Phthalocyanines Covalently Linked by a One Atom Oxygen Bridge

The diiminoisoindolines obtained from 4-neopentoxyphthalonitrile and bis[3, 4-dicyanophenyl] ether gave, in a mixed condensation reaction, binuclear and trinuclear phthalocyanines covalently linked by one atom oxy bridges with the dimer predominating. The underivatized 4-neopentoxyphthalonitrile condensed with the diiminoisoindoline of bis[3,4-dicyanophenyl] ether in a cross reaction to give the same dimer and trimeric phthalocyanines but the trimer predominated in this reaction. A cobalt derivative of bis-2-[19,16,23-trineopentoxyphthalocyaninyl] ether, the binuclear phthalocyanine, was prepared. All phthalocyanines exhibited parent ions in their fast atom bombardment mass spectra.