Use of a Metallation Reaction to Obtain Substituted 2-(5-Methyl-2-thiazolyl)ethanols

The interaction of anions, obtained by treating 2,4,5-trimethylthiazole and 2,5-dimethyl-4-phenylthiazole with butyllithium, with aliphatic and aromatic aldehydes leads to substituted 2-thiazolyl-1-ethanols. It was established that the metallation reaction occurs at the 2-methyl group of the thiazoles. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1038–1043, July, 2005.     

纳米nah高化学反应活性

纳米氢化钠;氯苯氢解;肉桂醛选择还原;二甲亚砜金属取代反应;烯烃催化加氢     

Allylmetallation of benzoazaheterocycles with allylic derivatives of zinc. Synthesis of 1,4-ethano-2,3-dihydroisoquinolines and allylated heterocycles

Allylmetallation of isoquinolines, quinoline, and quinoxaline with allylic derivatives of zinc was examined for the first time. A convenient procedure was discovered and developed for the synthesis of 1,4-ethano-2,3-dihydroisoquinolines based on the reactions of isoquinolines with allylic derivatives of zinc. This multistage process involves double allylmetallation of the heterocyclic ring followed by cyclization through intramolecular carbometallation of the C=C bond. The structures of three key derivatives of 1,4-ethano-2,3-dihydroisoquinoline were established by X-ray diffraction analysis. The reactions of quinoxaline with allyl- and methallylzinc bromide proceeded stereospecifically to form trans-2,3-diallylated 1,2,3,4-tetrahydroquinoxalines. Heating of quinoline with methallylzinc bromide in THF afforded 4-methallylquinoline in nearly quantitative yield. The initially formed 1,4-metallation product underwent aromatization through elimination of HZnBr.     

Metallation of 2,4-Dialkoxy-5-bromopyrimidine and Formylation with Dimethylformamide: Isolation of 2,6-Dialkoxy-5-dimethylaminopyrimidine-4-carboxaldehyde

Direct metallation of 2,4-dialkoxy-5-bromopyrimidine with lithium diisopropylamide and consequent trapping by dimethylformamide resulted unexpectedly in the formation of 2,6-dialkoxy-5-dimethylaminopyrimidine-4-carboxaldehyde via displacement of bromine by dimethylamine moiety of dimethylformamide.     

Serendipitous synthesis of trimetallic porphyrazine triads

We report the synthesis and characterization of structurally unusual porphyrazine triads with three macrocycles bound to a central pyrazine core. These trimacrocyclic complexes were accidentally discovered during studies on the peripheral metallation of porphyrazinediamines. The crystal structure of the tri-zinc porphyrazine triad is described and the spectroscopic properties including electronic absorption spectra of this complex and the corresponding magnesium, free-base, and copper derivatives are reported.     

Organometallic Approach to the Functionalization of Alkyl Groups Containing 1‐Phenylpyrroles

Novel regioselective methods have been developed for the mono‐ and difunctionalization of alkyl groups containing 1‐phenylpyrroles using different organometallic reagents. Tailoring the reagents and conditions allowed us to prepare several new mono‐ and rotationally restricted dicarboxylic acid derivatives of 1‐(alkylphenyl)pyrroles in good yields.     

Design and synthesis of binucleating macrocyclic clefts derived from Schiff-base calixpyrroles

The syntheses, characterisation and complexation reactions of a series of binucleating Schiff-base calixpyrrole macrocycles are described. The acid-templated [2+2] condensations between meso-disubstituted diformyldipyrromethanes and o-phenylenediamines generate the Schiff-base pyrrolic macrocycles H(4)L(1) to H(4)L(6) upon basic workup. The single-crystal X-ray structures of both H(4)L(3).2 EtOH and H(4)L(6).H2O confirm that [2+2] cyclisation has occurred, with either EtOH or H2O hydrogen-bonded within the macrocyclic cleft. A series of complexation reactions generate the dipalladium [Pd2(L)] (L=L(1) to L(5)), dinickel [Ni2(L(1))] and dicopper [Cu2(L)] (L=L(1) to L(3)) complexes. All of these complexes have been structurally characterised in the solid state and are found to adopt wedged structures that are enforced by the rigidity of the aryl backbone to give a cleft reminiscent of the structures of Pacman porphyrins. The binuclear nickel complexes [Ni2(mu-OMe)2Cl2(HOMe)2(H(4)L(1))] and [Ni2(mu-OH)2Cl2(HOMe)(H(4)L(5))] have also been prepared, although in these cases the solid-state structures show that the macrocyclic ligand remains protonated at the pyrrolic nitrogen atoms, and the Ni(II) cations are therefore co-ordinated by the imine nitrogen atoms only to give an open conformation for the complex. The dicopper complex [Cu2(L(3))] was crystallised in the presence of pyridine to form the adduct [Cu2(py)(L(3))], in which, in the solid state, the pyridine ligand is bound within the binuclear molecular cleft. Reaction between H(4)L(1) and [Mn(thf){N(SiMe(3))2}2] results in clean formation of the dimanganese complex [Mn2(L(1))], which, upon crystallisation, formed the mixed-valent complex [Mn2(mu-OH)(L(1))] in which the hydroxo ligand bridges the metal centres within the molecular cleft.     

Synthesis,Reactivity and Antimicrobial Activity of a Series of 2-Arylamino-1,3-selenazoles

A series of 2-arylamino-1,3-selenazoles was synthesized and their reactivity was studied. The 2-arylamino-1,3-selenazoles and their reaction products were characterized by various spectroscopic methods and X-ray diffraction. In addition, the antimicrobial activity of the 2-arylamino-1,3-selenazoles in a panel of seven bacteria and fungi was examined.     

Regioselective synthesis and metallation of tributylstannylfluoropyrazines. Application to the synthesis of some new fluorinated liquid crystals diazines. Part 34

Starting from fluoropyrazine, a general synthetic route including metallation and palladium-catalyzed cross-coupling reactions is described to access to rod-like alkylaryl or diarylpyrazines. Among them, some have liquid crystalline properties.