SbCl3-catalyzed solvent-free Friedel–Crafts reaction of phenols with mandelic acids to 3-aryl benzofuran-2(3H)-ones: Synthesis of spirocyclic 2,3-dihydrobenzofuran-2-ones

A facile, SbCl₃-catalyzed, one-pot, tandem Friedel–Crafts/lactonization reaction of phenols and mandelic acids has been developed under solvent-free conditions to afford 3-aryl benzofuran-2(3H)-ones in good to high yields (52–90%). Additionally, the utility of 3-aryl benzofuran-2(3H)-ones is demonstrated by using them as precursors in the synthesis of a new class of spirocyclic benzofuran-2-ones using classical synthetic methodologies.     

Darzens reaction in the synthesis of 3-(α-chloroalkyl)quinoxalin-2(1H)-ones

A two-stage method was developed for the synthesis of 3-(α-chloroalkyl- and α-chlorophenylalkyl)-quinoxalin-2(1H)-ones proceeding from methyl chloroalkyl- and chlorophenylalkylpyruvates obtained by Darzens reaction from methyl dichloroacetate and appropriate aldehydes in the presence of t-BuOK.     

Cupro(I)-π-complexes with 1-allyloxybenzotriazole: Synthesis and crystal structure of CuBF4 · 2C6H4N3(OC3H5) · H2O and CuCF3COO · C6H4N3(OC3H5)

The crystals of copper(I) π-complexes CuBF₄ · 2C₆H₄N₃(OC₃H₅) · H₂O (I) and CuCF₃COO · C₆H₄N₃(OC₃H₅) (II) were obtained by alternating-current electrosynthesis and studied by X-ray diffraction: I, space group P2₁/n, a = 10.226(8), b = 13.233(10), c = 16.30(1) Å, β = 98.13(1)°, V = 2249(2) ų, Z = 4, R = 0.0705, 577 reflections; I, space group P $ P\bar 1 The crystals of copper(I) π-complexes CuBF₄ · 2C₆H₄N₃(OC₃H₅) · H₂O (I) and CuCF₃COO · C₆H₄N₃(OC₃H₅) (II) were obtained by alternating-current electrosynthesis and studied by X-ray diffraction: I, space group P2₁/n, a = 10.226(8), b = 13.233(10), c = 16.30(1) ?, β = 98.13(1)°, V = 2249(2) ?³, Z = 4, R = 0.0705, 577 reflections; I, space group P , a = 8.8625(7), b = 9.0647(4), c = 9.1650(5) ?, α = 68.37(2)°, β = 85.31(3)°, γ = 69.86(2)°, V = 646(4) ?³, Z = 2, R = 0.1354, 2669 reflections. In compound I, the tetrahedrally distorted trigonal pyramidal environment of the copper atom comprises two nitrogen atoms of two organic molecules (L), the C=C bond of another L molecule, and the O atom of the water molecule. Due to the bridging function of L molecule, infinite chains [Cu · 2C₆H₄N₃(OC₃H₅) · H₂O] _n are formed in the structure along the y axis. The chains are, in turn, assembled into layers through strong O-H…F hydrogen bonds involving both hydrogen atoms of the water molecule and fluorine atoms of the BF₄⁻ anion. In compound II, two bridging oxygen atoms of two trifluoroacetate anions and two copper atoms form a centrosymmetric dimer. The nitrogen atom of the benzotriazole ring of one molecule L and the C=C double bond of the allyl group of the other molecule L complete the distorted coordination tetrahedron of the metal atom. Owing to the bridging function of the L molecule, the [CuCF₃COO · C₆H₄N₃(OC₃H₅)]₂ dimers are connected to form infinite double chains associated in a three-dimensional framework by only weak interactions. The replacement of the covalently bonded trifluoroacetate anion by an outer-sphere tetrafluoroborate ion opens up the possibility for metal atom binding to three L molecules simultaneously. Original Russian Text ? E.A. Goreshnik, M.G. Mys’kiv, 2008, published in Koordinatsionnaya Khimiya, 2008, Vol. 34, No. 11, pp. 826–830.     

Synthesis of novel 6-methyl-4-sulfanylfuro[3,4-с]pyridin-3(1H)-ones

Chemistry of Heterocyclic Compounds - Alkylation of 6-methyl-4-thioxo-4,5-dihydrofuro[3,4-c]pyridin-3(1H)-one in an alkaline medium proceeds regioselectively at the sulfur atom to form sulfanyl...     

Synthesis and crystal structure of KBi(C6H4O7) · 3.5H2O

A novel compound, KBi(C₆H₄O₇) · 3.5H₂O (I), has been synthesized in the Bi(NO₃)₂-K₃(HCit) system (HCit^3? is an anion of citric acid C₆H₈O₇) at a component ratio (n) of 8 in a water-glycerol mixture, and its crystal structure has been determined. The crystals are unstable in air. The crystals are triclinic: a = 7.462 Å, b = 10.064 Å, c = 17.582 Å, α = 100.27°, β = 99.31°, γ = 105.48°, V = 1221.2 ų, Z = 2, space group $P\bar 1$ . In the structure of I, asymmetric binuclear fragments [Bi₂(Cit^4?)₂(H₂O)₂]^2? are linked through inversion centers into polymeric chain anions. Ions K⁺ and crystal water molecules are arranged in channels between the chains. The Bi(1)...Bi(2) distances in the binuclear fragment are 4.62 Å, and the Bi(1)...Bi(1) and Bi(2)...Bi(2) distances between bismuth atoms in the chain are 5.83 and 5.95 Å, respectively. The chains are linked through bridging oxygen atoms of the ligands Cit to form layers. In the centrosymmetric four-membered chelate ring Bi₂O₂ formed through Bi-O(Cit) bonds, the distances Bi(1)-Bi(1) are equal to 4.55 Å, and Bi(1)-O are 2.66 and 2.84 Å. The Bi-O bond lengths in I are in the range 2.12–3.16 Å. The Cit ligands act as hexadentate chelating/bridging ligands.     

The reaction of (α-haloalkyl)silanes with Lewis acids

The kinetics for the reaction of three (α-haloalkyl0silanes with antimony pentafluoride in nitromethane have been studied using NMR to follow the reaction. For tertiary (α-haloalkyl)silanes, the reaction is stepwise with the intermediate formation of a charged species. The rearrangement–elimination reaction of this intermediate is sensitive to the Lewis acid used and to the inductive character and size of the alkyl groups attached to silicon. The kinetic and thermodynamic data are consistent with a mechanism involving nucleophilic attack at silicon before or during the rate determining alkyl migration or alkene elimination.     

Synthesis of 3-acylindoles via decarboxylative cross-coupling reaction of free(N–H) indoles with α-oxocarboxylic acids

A convenient and general method for acylation of free(N–H) indoles via palladium-catalyzed decarboxylative cross-coupling reaction was developed. This process provided a useful method for the preparation of diverse 3-acylindoles in high yields utilizing a reaction with readily accessible reactants under mild conditions.     

Reaction of α-Haloketones with ortho-Dihydroxy-2H-1-benzopyran-2-ones. Formation of α-Pyrano-1,5-benzodioxapines-A New Heterocyclic System

Reaction of 7,8-dihydroxy-2H-1-benzopyran-2-one, and its 4-methyl derivative, with α-haloketones affords α-pyrano-1,5-benzodioxapines, while 3-chloro-4-methyl-7,8-dihydroxy-2H-1-benzopyran-2-one gives α-pyrano-1,4-benzodioxane. The structures of the compounds were deduced using a combination of ¹H nmr, ¹³C nmr (BB, DEPT), HETCOR, NOESY, and selective INEPT techniques and molecular modeling.     

Synthesis of chiral α-(tetrazol-1-yl)-substituted carboxylic acids

Optically active α-(tetrazol-1-yl)-substituted carboxylic acid OBO-esters were synthesized from the corresponding a-isocyano OBO-esters and trimethylsilyl azide in up to 92% yield. Subsequent acidic hydrolysis proceeds without epimerization and makes it possible to prepare enantiomerically pure α-(tetrazol-1-yl)-substituted carboxylic acids in up to 89% yield.

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Synthesis and crystal structure of a neutral open framework cobalt(II) phosphate Co6(PO4)4·7H2O with a channel structure

Using tri-ethyl phosphate as a phosphate source, the hydrothermal reaction of cobalt(II) oxalate di-hydrate, zinc oxide and 1,8 di-amino octane at 200°C gave purple crystals of Co₆(PO₄)₄?·?7H₂O (1), along with a mixture of open-framework zinc–cobalt phosphates Co–Zn–HPO₄, and Co₃(HPO₄)₂(2OH). Compound 1, has been characterized by thermal analysis, FTIR and single crystal X-ray diffraction. The single crystal structure of Co₆(PO₄)₄?·?7H₂O reveals cobalt in four, five and six-fold coordination with linkages through the bridging water molecules and the oxygen atoms of the phosphate in the subunits. Four subunits are connected together through the oxygen atoms (PO₄), to form the three dimensional open framework structure, with a 20-member ring channel that hosts two uncoordinated water molecules. Thermal removal of the water molecules occurs between 400–600°C, with the collapse of the structure above 600°C.     

Synthesis of 3-Phenyl-6-formyl-3, 4-dihydro-2H-1, 3-benzoxazine

Benzoxazine is a novel class of thermosetting resins, which possesses lots of outstanding properties such as no by-products and near-zero shrinkage during polymerization as well as good molecular design flexibility1-2. Furthermore, polybenzoxazines (PBZs)…     

Synthesis and domino reactions of polymethylene-3-cyanopyridine-2(1Н)-thiones

A new and facile three-component method was developed for the synthesis of polymethylene-3-cyanopyridine-2(1Н)-thiones by the domino Knoevenagel → Michael → heterocyclization → dehydrogenation reaction from cycloalkanones, cyanothioacetamide, and polymethoxy-substituted benzaldehydes. The final dehydrogenation step was found to involve arylidenecyanothioacetamide. The resulting pyridinethiones and 4-chloroacetoacetic ester were introduced into the domino S_N2 → Thorpe-Ziegler → Guareschi-Thorpe reaction to synthesize tetracyclic dipyridothiophenes. Starting from these compounds, 8,9-polymethylenepyranothienodipyridines were also synthesized by the domino Knoevenagel → Michael → hetero-Thorpe-Ziegler reaction. Furthermore, a method for the synthesis of thienodipyridine annulated to the steroid skeleton is proposed.     

Synthesis of 3-oxoesters and functional derivatives of pyrimidin-4(3<Emphasis Type="Italic">Н</Emphasis>)-one based on 1-(2,6-dihalophenyl)cyclopropan-1-carboxylic acids

Special features of the synthesis and chemical transformations of novel functional derivatives of 6-[1-(2,6-dihalophenyl)cyclopropyl]pyrimidin-4(3H)-one and ethyl esters of 3-[1-(2,6-dihalophenyl)cyclopropyl]-2-methyl-3-oxopropanoic acids prepared from 2-(2,6-dihalophenyl)acetonitriles have been revealed. Novel achiral structural analogs of experimental anti-HIV agent МС-1501 have been synthesized.     

Mn(Ⅲ)-mediated radical reaction of 2-isocyano-6-alkenyl(alkynyl)benzonitriles with arylboronic acids:Synthesis of pyrroloisoquinoline derivatives

A Mn(Ⅲ) mediated radical reaction of new designed multi-functionalized 2-isocyano-6-alkenyl(alkynyl)benzonitriles with arylboronic acids has been developed.This reaction provides a method for the synthesis of pyrroloisoquinoline derivatives through the formation of two C-C bonds and one C-N bond via radical cascade cyclization in one step.     

(NH4)(CN3H6)2[UO2(C2O4)2(NCS)] · 2H2O: Synthesis and crystal structure

A single-crystal X-ray diffraction study (NH₄)(CN₃H₆)₂[(UO₂(C₂O₄)₂(NCS)] · 2H₂O (I) was carried out. The crystals are orthorhombic, space group P2₁2₁2₁, Z = 4, with the unit cell parameters a = 6.668(2) Å, b = 13.463(4) Å, c = 23.086(6) Å. The main structural units of the crystals of I are insular complex anions [(UO₂)(C₂O₄)₂(NCS)]^3?. They belong to the crystal-chemical group AB ₂ ⁰¹ M¹ (A = UO ₂ ²⁺ ) of uranyl complexes and are linked into a three-dimensional framework through electrostatic interactions and hydrogen bonds with the participation of ammonium and guanidinium cations and crystal water molecules.     

Tansition metal complexes with 2-(1-(carboxymethyl)-2-methyl-1H-benzimidazol-3-ium-3-yl)acetate (HL): Synthesis and crystal structure of [Co(L)2(H2O)4] · 6H2O and [Cu(L)2(H2O)2] · 4H2O

Transition metal complexes of 2-(1-(carboxymethyl)-2-methyl-1H-benzimidazol-3-ium-3-yl)acetate (HL), namely [Co(L)₂(H₂O)₄] · 6H₂O (I) and [Cu(L)₂(H₂O)₂] · 4H₂O (II), have been synthesized by a hydrothermal procedure and characterized by X-ray crystallography, CIF files CCDC nos. 1007524 (I), 1007525 (II). Both I and II are mononuclear molecules. In I, the Co²⁺ ion is in octahedral coordiantion environment and surrounded by four O atoms from water molecules and two carboxylate O atoms of two deprotonated ligand (L^?) occupied six culmination. While in II, the Cu²⁺ ion is located in a square-planar geometry, bounded to two aqua O atoms and two carboxylate O atoms from L^?.