M. E. Vol'pin

Ionic bromination of ethane and other alkanes (cycloalkanes) with bromine catalyzed by the polyhalomethane·2AlBr3 aprotic organic superacids under mild conditions

Abstract The polyhalomethane·2AlBr 3 aprotic organic superacids were shown to effectively catalyze low-temperature ionic bromination of (cyclo)alkanes. Ethane readily reacts with Br 2 at 55–65 °, affording mainly 1,2-dibromoethane. Propane, butane, and C 5 -C 6 cycloalkanes react at [fd9365-1], resulting in monobromides with high yields and good selectivity.

Crown compounds for anions. A spinning top-shaped complex of cyclic pentameric perfluoroisopropylidenemercury with two chloride anions

Abstract It has been found that cyclic pentameric perfluoroisopropylidenemercury, [(CF 3 ) 2 CHg] 5 , is capable of forming complexes with [PPh 4 ] + Cl − and [PPh 4 ] + Br − of the type {[(CF 3 ) 2 CHg] 5 X 2 } 2− [PPh 4 ] 2 + (X = Cl or Br). According to an X-ray diffraction study, the chloride anions in the complex of [(CF 3 ) 2 CHg] 5 with [PPh 4 ] + Cl − are located above and below the mercury-containing metallacycle, each Cl − anion being coordinated with all the five mercury atoms of [(CF 3 ) 2 CHg] 5 .

Transformatioms of cycloalkanes under the action of acyl halides in the presence of AIBr3.

Abstract Cycloalkanes have been found to react with acyl halides in the presence of AIBr3, (mole ratio RCOX:AIBr3 = 1:2) under very mild conditions affording products of hydrocarbon oxidative coupling or/and hydrocarbon acylation.

Addition of amino acids and dipeptides to fullerene C60 giving rise to monoadducts

The authors have developed a general method for the direct addition of amino acids and dipeptides of various structures to fullerene C{sub 60}. In all cases the addition involves the amino group. The reaction proceeds when the solutions of fullerene and an amino acid (or dipeptide) are mixed at 50-100 {degrees}C. The fullerene derivatives of the following amino acids and dipeptides have been obtained: glycine, p-aminobenzoic acid, {omega}-aminocaproic acid, L-proline, L-alanine, L-alanyl-Lalanine, D,L-alanyl-D,L-alanine, glycyl-L-valine. The adduct of methyl L-ananinate with C{sub 60} was also prepared.

An effective formylation of adamantane with CO initiated by the aprotic organic superacid CBr4·2AlBr3 under mild conditions

Abstract The reaction of adamantane with carbon monoxide at −45° ÷ +20° C over 0.5–2 h, catalyzed by the aprotic organic superacid CBr 4 ·2AlBr 3 , is described. The formylation of adamantane under CO atmosphere at 0 ÷ +20°C in the presence of methylcyclopentane as a source of hydride ion affords 1-adamantanecarbaldehyde (1) in yield 70–72% on adamantane for 1 h.

Functionalization of saturated hydrocarbons

Alkanes and cycloalkanes (isobutane, butane, isopentane, isohexane, and methylcyclopentane) react with benzene or bromobenzene at 0–20 °C in the presence of RCO+Al2X7− complexes (R=Me, Pr, or Ph; X=Cl or Br) to give products of the alkylacylation of arenes. The yields of alkylated aromatic ketones reach 60–87 % in 5–30 min, whereas the yields of unalkylated aromatic ketones (the competitive reaction) reach 0–40 %. The reactions of isobutane or isopentane with benzene result exclusively inpara isomers oft-BuC6H4COR or a mixture of Me2(Et)CC6H4COR and Me(i-Pr)CHC6H4COR isomers (1∶1), respectively. The reaction of isobutane with benzene also proceeds regioselectively and gives only one isomer, 2-Br-t-BuC6H4COR.

Formation of aromatic amines from dinitrogen complexes [Cp2TiAr]2N2 (Ar = C6H5, m-CH3C6H4)

It has been shown that the reaction of the dinitrogen complex [Cp2TiC6H5]2N2 with a mixture of C6H5Li and Li in ether results in the formation of ammonia and aniline after hydrolysis. Under optimum conditions, the yield of aniline is 12 mol% per initial complex and the ammonia yield is 36 mol%. In the absence of lithium neither ammonia nor aniline are formed, while in the absence of phenyllithium only ammonia is produced. The interaction of [Cp2TiC6H5]2N2 with p- m- and o-tolyllithium reagents in the presence of lithium also gives aromatic amines and ammonia after hydrolysis. Similar results have been obtained for the dinitrogen complex [Cp2Ti(m-CH3C6H4)]2N2. The mechanism of the reaction found is discussed.

Unprecedented alkylation of pentafluorobenzene with propane

Propane has been found to alkylate pentafluorobenzene in the presence of aprotic organic superacids CBr4·nAlBr3 (n = 1 or 2) in CH2Br2 solution at 0°, giving C6F5Pri (1) in almost quantitative yield. In the absence of propane at the 20°, pentafluorobenzene reacts with CBr4·2AlBr3 to form C6F5CBr3 in 40 % yield.

AMINO ACID AND PEPTIDE DERIVATIVES OF FULLERENE

A general method for the synthesis of amino acid and peptide derivatives of fullerene (ADF) was developed, and the physicochemical properties of the compounds obtained were studied. ADF were shown to penetrate into liposomes and to exhibit adjuvant properties and antiviral activity.

Functionalization of saturated hydrocarbons by aprotic superacids 5. Regioselective carbonylation of propane in an organic solvent initiated by aprotic organic superacids CX4·nAlBr3 (X = Br, Cl;n = 1 or 2)

Aprotic organic superacids CX4 ·nAlBr3 (X = Br, CI; n = 1 or 2) are effective initiators of carbonylation of propane with CO in an organic solvent at -10 to -20 °C.