Identification of randomers of tetra(tert-butyl)porphyrazine

Randomers of tetra(tert-butyl)porphyrazine, the assignment of which was made on the basis of data from mass spectrometry and high-resolution PMR spectroscopy, were isolated by high-performance liquid column chromatography.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1261–1263, September, 1988.     

Synthesis and chemical transformations of mono- and disubstituted cyanamides

The review briefly discusses the known methods for the preparation of substituted cyanamides, their typical transformations, and some aspects of practical applications of these compounds in medicine, various branches of industry, and agriculture.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1439–1454.Original Russian Text Copyright © 2004 by Nekrasov.Dedicated to the memory of Prof. Yu.S. Andreichikov     

Radial tetra(ferrocenyl)- and tetra(cymantrenyl)cyclobutadienecobalt complexes: Synthesis and structures

Novel radial tetra(ferrocenyl)- and tetra(cymantrenyl)cyclobutadienecobalt complexes were prepared by metal carbonyls free protocol of [2 + 2] cycloaddition reaction of 1,2-diferrocenyl- or 1,2-dicymantrenylethynes with chlorotris(triphenylphospine)cobalt(I) and carboethoxycyclopentadienide sodium with good yields. The molecular structure of these products was confirmed with X-ray analysis, and their electrochemical behavior was studied.     

Metal-catalyzed silacyclopropanation of mono- and disubstituted alkenes

As an alternative to the strongly reducing conditions necessary for the formation of silacyclopropanes, silylene transfer was developed as a mild, functional group tolerant method of silacyclopropanation. Complex silacyclopropanes were formed from functionalized alkenes using cyclohexane di-tert-butyl silacyclopropane, 1, as the source of t-Bu(2)Si. Di-tert-butyl silylene can be generated from 1 through the use of a catalytic amount of a metal salt. At -27 degrees C, silver triflate catalyzes the transfer of t-Bu(2)Si from 1 to mono- and disubstituted alkenes stereospecifically and diastereoselectively. In situ functionalization of silacyclopropanes with catalytic zinc bromide and methyl formate provides for an expedient one-flask synthesis of complex oxasilacyclopentanes from alkenes.     

Synthesis and characterization of octakis-(9-anthracenylmethylthio) substituted novel porphyrazines

A magnesium porphyrazinate carrying eight (9-anthracenyl) units on the periphery through flexible methylthio-bridges has been synthesized by cyclotetramerization of 3,4-(9-anthracenylmethylthio) pyrroline-2,5-diimine in the presence of magnesium butanolate. The metal-free derivative was obtained by treatment with trifluoroacetic acid and further reaction of this product with copper(II) acetate, zinc(II) acetate, and cobalt(II) acetate led to the metal porphyrazinates (M = Cu, Zn, Co). These novel compounds were characterized by elemental analysis, together with FT-IR, ¹H-NMR, UV–Vis, and mass spectral data.     

Synthesis of mono- and disubstituted porphyrins: A- and 5,10-A2-type systems

General syntheses have been developed for meso-substituted porphyrins with one or two substituents in the 5,10-positions and no beta substituents. 5-Substituted porphyrins with only one meso substituent are easily prepared by an acid-catalyzed condensation of dipyrromethane, pyrrole-2-carbaldehyde, and an appropriate aldehyde using a "[2+1+1]" approach. Similarly, 5,10-disubstituted porphyrins are accessible by simple condensation of unsubstituted tripyrrane with pyrrole and various aldehydes using a "[3+1]" approach. The yields for these reactions are low to moderate and additional formation of either di- or monosubstituted porphyrins due to scrambling of the intermediates is observed. However, the reactions can be performed quite easily and the desired target compounds are easily removed due to large differences in solubility. A complementary and more selective synthesis involves the use of organolithium reagents for S(N)Ar reactions. Reaction of in situ generated porphyrin (porphine) with 1.1-8 equivalents of RLi gave the monosubstituted porphyrins, while reaction with 3-6 equivalents of RLi gave the 5,10-disubstituted porphyrins in yields ranging from 43 to 90 %. These hitherto almost inaccessible compounds complete the series of different homologues of A-, 5,15-A(2)-, 5,10-A(2)-, A(3)-, and A(4)-type porphyrins and allow an investigation of the gradual influence of type, number, and regiochemical arrangement of substituents on the properties of meso-substituted porphyrins. They also present important starting materials for the synthesis of ABCD porphyrins and are potential synthons for supramolecular materials requiring specific substituent orientations.     

Anodic oxidation of mono- and disubstituted 1,4-dimethoxybenzenes

The electrochemical oxidation of mono- and disubstituted 1,4-dimethoxybenzene derivatives with zero, one, and two benzylic CH(2)X groups (X = OAc, Cl, OH) (5a-c and 6a-c) has been carried out by using both constant-current and controlled-potential techniques in methanol and in the presence of different electrolytes and working electrodes. Constant-current electrolysis in KOH-methanol solutions yielded mostly the corresponding 1,4-quinone derivatives from 5a-c and 6b, whereas the disubstituted 1,4-dimethoxybenzenes 6a,c underwent side-chain oxidation to form 2,5-dimethoxyterephthalaldehydes. Upon alteration of the medium from the commonly used basic KOH-methanol to neutral LiClO(4)-methanol, a new spectrum of products was achieved in most cases, involving novel coupling products from monosubstituted substrates and quinone derivatives from disubstituted ones. Controlled-potential oxidation at the glassy carbon anodes and in a neutral LiClO(4)-methanol medium led to more complex mixtures of products, namely, polymers and new coupling products from monosubstituted substrates and quinones and side-chain oxidation (or substitution) products from the disubstituted ones. Three new coupling products were isolated and characterized by X-ray measurements.     

Synthesis of tetra(4-sulfonatophenyl)porphin derivatives

Corresponding sulfonamides were obtained by the action of ammonia and amines on tetra(4-sulfonatophenyl)porphin fluorides and chlorides. Their structure was confirmed by IR, PMR, and electronic spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 770–772, June, 1988.     

Solvent effect on the photogeneration of singlet molecular oxygen by copper tetra(tert-butyl)phthalocyanine

The photogeneration of the singlet molecular oxygen (¹O₂) by copper tetra(4-tert-butyl) phthalocyanine in organic solvents of different nature was substantiated. The apparent quantum yields of ¹O₂in benzene and pyridine were determined. The data obtained indicate an influence of the coordinating properties of the solvent on the ¹O₂yield. However, this factor is not “critical” as in the case of photogeneration of ¹O₂by copper tetra(5-tert-butylpyrazino)porphyrazine.     

Octakis(ferrocene)-substituted porphyrazines

Metal-free porphyrazine and metal porphyrazinates (M = Mg, Cu, Co or Zn) substituted with eight ferrocene moieties on the periphery through flexible alkylthio-bridges have been synthesised in a multi-step reaction sequence. The new compounds have been characterised by elemental analyses, i.r., ¹H- and ¹³C-n.m.r., u.v.–vis. and mass spectra. The electrochemical investigation of porphyrazines indicates that all the ferrocene moieties are oxidised at the same potential, confirming the lack of any interaction among ferrocene groups or between ferrocenes and the porphyrazine core.     

(NHC)Copper(I)-catalyzed [3+2] cycloaddition of azides and mono- or disubstituted alkynes

A versatile and highly efficient catalyst for the Huisgen cycloaddition reaction has been developed. Previously isolated or in situ generated azides yielded 1,2,3-triazoles with differently substituted alkynes in the presence of a [(NHC)CuBr] complex (NHC = N-heterocyclic carbene). Extremely high reaction rates and excellent yields were obtained in all cases. This catalytic system fulfils the requirements of "click chemistry" with its mild and convenient conditions, notably in water or solvent free reactions and simple isolation with no purification step. Furthermore, for the first time, an internal alkyne was successfully used in this copper-catalyzed cycloaddition reaction. DFT calculations on this particular system allowed for the proposition of a new mechanistic pathway for disubstituted alkynes.     

三苯基 合二钼四正丁基铵盐的合成和鉴定

在有机溶剂中使多种单芳基 酸与钼酸钠进行反应, 合成了中间体ArSbO(OH)2、Ar2SbCl3和Ar3SbI2, 发现只有后者可与[(n-C4H9)4N]2MoO4反应, 从而制得一种无色透明晶体[(n-C4H9)4N]2[(C6H5)3Sb(MoO4)2]·3H2O。     

Synthesis of tetra(1,4-dithiacyclohexene)porphyrazine and its metal complexes

The syntheses of tetra, 1, 4-dithiacyclohexene)porphyrazine and its lithium salt, obtained by reaction of 3,6-dithiahexene-1,2-dicarbonitrile with lithium amylate, are described. A series of metal complexes of tetra(1,4-dithiacyclohexene)porphyrazine has been synthesized starting from 3,6-dithiacyclohexene-1,2-dicarbonitrile and the salts of the corresponding metals as well as from the free ligand and metal chlorides.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 603–606, May, 1986.     

Synthesis of non-peripherally substituted tetra(dihexylmalonate) alcohol soluble phthalocyanines

Dimethyl-(2,3-dicyanophenyl)malonate was prepared by the reaction of dimethylmalonate and 3-nitrophthalonitrile. A cyclotetramerization reaction of dimethyl-(2,3-dicyanophenyl)malonate with the corresponding divalent metal salt was achieved in hexanol in the presence of DBU, affording the non-peripherally substituted tetra(dihexylmalonate) Cu(II), Pd(II), and Co(II) phthalocyanines. Transesterification occurred under these reaction conditions, so that methyls in the phthalonitrile derivative were converted into hexyl groups during phthalocyanine formation in hexanol. The new compounds were characterized by elemental analyses, FT-IR, ¹H-NMR, ¹³C-NMR, UV-Vis, and mass spectral data.     

Synthesis and characterization of mono- and bis(pentafluorosulfur)diacetylene

The synthesis of novel, high density, diacetylene monomers has been achieved by the preparation of mono- and bis(pentafluorosulfur) diacetylene. The derivatives are readily prepared by the addition of pentafluorosulfur bromide (SF₅Br) to diacetylene (C₄H₂) and subsequent dehydrobromination. Details of the synthesis and properties of these compounds are discussed.     

Reaction of 2.6-diphenyl-4-pentafluorophenylverdazyl with disubstituted mono- and dibromomethanes

Dicyano- and dicyanoethoxycarbonylbromomethane cause fragmentation of 2,6-diphenyl-4-pentafluorophenylverdazyl to 1,3,5-trisubstituted 1,2,4-triazoles. Trifluoro-methylsulfonylcyano- and trifluoromethylethoxycarbonyldibromomethane acylate the dazyl radical to give 1-R-2,6-diphenyl-4-pentafluorophenyl-1,2,3,4-tetrahydro-symtetrazines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1251–1254, September, 1989.