Zur Struktur der Tetrahydro-4-phenylspiro([1]benzopyran-2,4′(1′H)-pyrimidin)-2′(3′H)-one bzw.-thione über Heterocyclen, 49. Mitt

The structures of tetrahydro-4-phenylspiro([1]benzopyran-2,4(1H)-pyrimidin)-2(3H)-ones and-thiones4 a, b resp., are proved by synthesis. 3-(2-methoxy-3,5-dimethylphenyl)-3-phenylpropionic acid11 b is prepared from 3,4-dihydro-6,8-dimethyl-4-phenylcoumarin10. The lithium salt of11 b reacts with isobutenyl-lithium to 1-(2-methoxy-3,5-dimethylphenyl)-5-methyl-1-phenyl-4-hexen-3-on12 a. 12 a is transferred with urea in acid medium and NH₄CNS resp. in a mixture of dihydro-6-[2-(2-methoxy-3,5-dimethylphenyl)-2-phenyläthyl]-4,4-dimethyl-2(1H)-pyrimidinone and-thione13 a, b and tetrahydro-6-[2-(2-methoxy-3,5-dimethylphenyl)-2-phenyläthyliden]-4,4-dimethyl-2(1H)-pyrimidinone and-thione14 a, b resp.14 b leads to13 a, b with H₂O₂. Heating of13 a, 14 a and14 b resp. with pyridin-HCl leads to the spiro compounds4 a, b.     

Oxodiperoxo molybdenum modified mesoporous MCM-41 materials for the catalytic epoxidation of cyclooctene

A hybrid heterogeneous catalyst system, which has been synthesized by covalently anchoring oxodiperoxo molybdenum chelate complexes onto the surface of mesoporous MCM-41, is highly active and truly heterogeneous for the liquid-phase epoxidation of cyclooctene with tBuOOH as the oxygen source.     

Die Berechnung von Einelektronen-Integralen in der SCF-Xα-SW-Methode: I. Die Normierung

A normalization of the wave functions by means of the theoretical exact Multiple-Scattering-(MS)-formalism is discussed within the framework of the SCF-X-SW-method. For the atomic and extramolecular regions the integrals of normalization can be easily determined and the results can be described by the corresponding electronic charges. The calculation of the integral of the interatomic region is problematic. The needful volume integration is only necessary to theGreen's functions of the wave functions and can be solved by means of the residual theory. The further analytical calculation of the surface integrals leads to a complicated formalism which can be numerically evaluated.

     

Synthesis and structural assignment of some N-substituted imidazopyridine derivatives

A synthesis of all possible N-alkylated 2-n-butyl-imidazo[4,5]pyridine isomers is described as well as their structural assignment by ¹H NMR spectroscopy. One of these derivatives, 2,-n-butyl-3-[2′- (1H-tetrazol-5-yl)-4-biphenylylmethyl]-3H-imidazo[4,5-b]pyridine 9 is a potent angiotensin II receptor antagonist.     

Untersuchungen zur reaktivität von metall-π-komplexen : XVIII. Elektrophile und nucleophile additionsreaktionen an siebenringliganden in tricarbonylmolybdän-komplexen: Synthese von [C7H9Mo(CO)3]BF4, C7H9Mo(CO)3Cl und [C7H9P(C6H5)3]BF4

C₇H₈Mo(CO)₃ reacts with HBF₄ and HCl by protonation of the ring ligand and formation of [C₇H₉Mo(CO)₃]BF₄ (I) and C₇H₉Mo(CO)₃Cl (II), respectively. The compounds are characterised by means of their IR and NMR data. The reaction of I with P(C₆H₅)₃ does not lead, as expected, to [C₇H₉Mo(CO)₃P(C₆H₅)₃]BF₄ (III) but to the phosphonium salt [C₇H₉P(C₆H₅)₃]BF₄ (IV), i.e. nucleophilic addition of the phosphine at the cycloheptadienyl group takes place. The structure of IV has been determined by ¹³C NMR measurements.     

Fluorine-Containing Organozinc Reagents Part 1 A Simple Synthesis of 2,2-Dichloro-3,3,3-trifluoropropanol

The title compound 1 , which can be regarded as a synthetic equivalent of substituted 1,1,1-trifluoroacetone 2 , is prepared by Zn-induced reductive addition of 1,1,1-trichloro-2,2,2-trifluoroethane ( 3 ) to formaldehyde ( 4 ). A brief survey of the scope of this C? C-bond formation leading to a variety of new CF₃-containing synthetic building blocks is also given.     

Pseudohalogenometallverbindungen: LVIII. Reaktionen von diphenylphosphorylazid und perfluor-n-hexylsulfonylazid mit triphenylphosphan-komplexen von platin(0), rhodium(I), iridium(I), ruthenium(0), kobalt(II) und kupfer(I)

Diphenylphosphorylazide N₃P(O)(OPh)₂ reacts with Pt(PPh₃)₃, Pt(PPh₃)₂(C₂H₄), trans-RhCl(CO)(PPh₃)₂, Ru(CO)₃(PPh₃)₂, CoCl₂(PPh₃)₂ and CuCl(PPh₃)₂ to give the azido complexes Pt(PPh₃)₂(N₃)R, Pt(PPh₃)₂(N₃)₂R₂, the urylene complex RhCl(PPh₃)₂(RNCONR) and the phosphine imine complexes Ru(CO)₃(RPPh₃)₂, CoCl₂(RNPPh₃)₂, CuCl(RNPPh₃)₂, respectively, (RP(O)(OPh)₂). The oxidative addition of n-C₆F₁₃SO₂N₃ to Pt(PPh₃)₄ and Pt(PPh₃)₂(C₂H₄) affords the complexes Pt(PPh₃)₂(N₃)R and Pt(PPh₃)₂(N₃)₂R₂, respectively, (RSO₂C₆F₁₃. The compounds are characterized by elemental analysis and by their IR spectra.     

Adducts of organogallium chlorides with hydrazines and the formation of dimeric dialkylgallium hydrazides possessing different ring sizes

The dialkylgallium chlorides R₂GaCl (R = Me, Et, CMe₃) reacted with hydrazines H₂N-N(H)R′ (R′ = CMe₃, C₆H₅) to form the adducts R₂ClGa ← NH₂-N(H)R′ (1-4), in which the gallium atoms are coordinated by the NH₂ nitrogen atoms of the hydrazine ligands. Treatment of these adducts with tert-butyllithium as a base afforded dialkylgallium hydrazides (R₂Ga-N₂H₂R′)₂ [5 (R = R′ = CMe₃) and 6 (R = CMe₃, R′ = C₆H₅)] by deprotonation of the hydrazine ligands and precipitation of LiCl in two cases only. The remaining adducts gave a substitution reaction at gallium or an unclear reaction course. The hydrazides 5 and 6 adopt different structures in the solid state. The tri(tert-butyl) compound 5 possesses a four-membered Ga₂N₂ heterocycle in its molecular core with two exocyclic N-N bonds, which represents the structural motif usually observed for dialkylgallium hydrazides. 6 has a five-membered Ga₂N₃ heterocycle with one endocyclic and one exocyclic N-N bond. That structure is preserved in solution as clearly shown by NMR spectroscopy. The behaviour of 5 in solution is more complicated, which may be caused by cis/trans isomerization.