A convenient one-step synthesis of symmetrical 1,1¢-dialkyl derivatives of isoindigo is described.In recent years, isoindigo (3,3¢-biindolinylidene-2,2¢-dione) and especially its N-and N,N¢-derivatives have attracted great attention not only as dyes, but also as substances that possess specific biological activity (antileukemia, antiproliferative, anti-inflammatory, etc.). [1][2][3][4] Thus, 1-(b-D-glucopyranosyl)isoindigo was found to be an antileukemia drug. 2-4 It has to be noted that the synthesis of 1-substituted isoindigos is often a multistep procedure. The best approach to the synthesis of isoindigo derivatives seems to be the dimerization of ketocarbenes generated from isatin derivatives. It has been assumed 5,6 that a mixture of 3-(triphenylphosphoranylidene)-1,3-dihydro-2H-indol-2-one and isoindigo is formed with moderate yield by the reaction of triphenylphosphine with isatin and 1-methylisatin through intermediate carbene formation. However, generation of carbenes from heterocyclic a-diketones under the action of trivalent phosphorus derivatives has been insufficiently studied. 7,8 Recently for the examples of acenaphthenequinone 9 and 1-acetylisatin, 10 we have shown that tris(diethylamino)phosphine is a more convenient reagent for a-ketocarbene generation. We have succeded 11 in trapping acenaphthenone carbene by fullerene C 60 . Herein we report the synthesis of some new isoindigo derivatives. The treatment of isatin derivatives 1 with tris(diethylamino)phosphine in dichloromethane at -60 °C for 10 minutes furnished tris(diethylamino)phosphine oxide (d P = 24.3) and the corresponding 1,1¢-disubstituted 3,3¢-biindolinylidene-2,2¢-diones (1,1¢-dialkylisoindigos) 2 in 60-91% yield (Scheme 1). The regiochemistry of deoxygenation at C3 in all cases was unequivocally established using 13 C NMR spectra data. The 13 C NMR spectrum of compound 2e displayed a signal at d = 167.8 as a triplet with spin-spin coupling constant 3 J HCNC = 3.5 Hz due to the two methylene protons, indicating the presence of one carbonyl group. The signal of C3 appeared at d = 133.5 as a doublet with 3 J HCCC = 2.6 Hz due to the proton at C4. Other spectral data also confirm the assigned structure of compounds 2a-e.A plausible mechanism of the reaction is shown in Scheme 2. It is reasonable to assume that the first stage of the reaction includes a one-electron transfer from phosphorus to the heterocyclic system to form ion radical pair 3. The next stage is likely to include the formation of the phosphonium salt 4 having a P-O-C fragment. Then this intermediate eliminates tris(diethylamino)phosphine oxide to give carbene 5, which under the reaction conditions undergoes dimerization to form the final products 2.In conclusion, a facile and convenient synthesis of isoindigo derivatives was achieved through a deoxygenation reaction of various 1-alkylisatins with tris(diethylamino)phosphine. The key step for the formation of a variety of isoindigos is a mild carbene generation followed by carbene dimerization. This methodology has sever...

This review contains some actual information about more interesting and perspective methods of coal and petroleum asphaltenes separation, fractionation, extraction, adsorption, and complexation. These are the most convenient and simple methods for isolating various components of asphaltenes. These methods are based on the electrostatic and donor–acceptor properties of the used reagents and on unique and incompletely understood phenomena. A promising area is the use of ionic liquids as a convenient and mild isolation of asphaltene components. Understanding and identifying the diverse molecular composition of asphaltene components will help one to understand their nature more fully in the future and, more precisely, physicochemical interactions and phenomena.

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In the present work, the first data on the catalytic activity of d-metal complexes of petroleum porphyrins obtained via two-stage re-metallization (acid demetallization with subsequent metalation) of high-purity petroleum vanadyl porphyrins are presented. During acid demetallization of petroleum vanadyl porphyrins, the highest yield (49%) and spectral purity of free petroporphyrin bases were achieved with concentrated sulfuric acid and a diluted solution of vanadyl porphyrins in chloroform. In the series of divalent cations of Mn, Fe, Co, Ni, Cu, and Zn, only the last four metals are complexed with demetallated petroporphyrins without significant changes in their component composition, whereas the interaction with Mn and Fe cations causes an evident structural transformation or even full degradation of petroporphyrin macrocycles, respectively. The composition and spectral purity of petroleum porphyrin-containing reactants and products were analyzed by FT-IR, UV-Vis, NMR, and MALDI-TOF mass spectroscopic methods. The obtained petroporphyrin-based d-metal complexes were assayed by the reaction of 2-mercaptoethanol oxidative dimerization, in which the copper porphyrins exhibited the highest catalytic activity.

A series of novel 2´ oxospiro[cyclopropafullerene 3,3´ indolines] was synthesized. Com pounds of this type have a significant potential for use as electron withdrawing components of light absorbing layers of solar cells.Efficiency of light conversion by solar cells based on crystalline silicon reaches 45-55%. 1 At the same time, toxicity, high cost of materials, and expensive technolo gies of cell preparation restrict the propagation of this type of power engineering. Therefore, search for novel materi als and simplification of technologies of their production become more and more topical. Progress in the area of organic photovoltaics achieved within the recent decade indicates that organic materials can compete with inor ganic materials. 2,3 The progress is caused, to a great ex tent, by the construction of plastic solar cells, whose light absorbing layers represent composites of semiconducting conjugated polymers (electron donors) with fullerene de rivatives (electron acceptors); the principle of their work is based on the theory of volume hypertransition. 4,5 Present ly, plastic cells are inferior to inorganic cells in efficiency. Nevertheless, such their advantages as lightness, flexibili ty, prognosticated cheapness, and simpler technologies of preparation form significant prerequisites for the develop ment of research in this area. 6-9 Devices, whose ac tive layers represent composites of poly(3 hexylthio phene) with 1 (3 methoxycarbonylpropyl) 1 phenyl [6,6] methanofullerene (system Р3НТ/[60]PCBM), are pioneers among plastic solar cells during the recent de cade. The efficiency of the first cells based on this com posite was 2.5-2.7%. 10,11 After developing the technolo gies and modifying the structures of the cells based on Р3НТ/[60]PCBM, the cells with an efficiency of 4.5-6.7% are presently prepared. 5,12-14 However, rela tively high cost of the composite, in particular, РСВМ, 15 and an insufficient efficiency of the cells do not allow plastic solar cells to work up a market. Numerous at tempts to substantially increase the efficiency of these cells due to the variation of the structure of methanofullerenes, including highest fullerenes, or to the combination of the polymer and fullerene fragments in one molecule are not too successful so far. 16-23 Nevertheless, in spite of modest success of organic photovoltaics, its advantages stimulate search for new approaches to design of fullerene derivatives. For instance, the first composite of trannu lene С 60 F 15 [C(COOMe) 3 ] 3 with Р3НТ was described. Although the cells based on this composite are sub stantially inferior to the reference composite based on Р3НТ/[60]РСВМ, the principal possibility of using tran nulene for the construction of photovoltaic materials was shown for the first time. 24 We detected an unusual effect in phosphorus containing methanofullerenes. An X ray diffraction analysis showed the intermolecular interaction of a lone electron pair of the O atom of the phosphoryl group with the electronic system of fullerene in a molecule of О...

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