An unusual pathway of the oxidation of diethyl ether by bismuth(v) derivatives

Di(tert-butylperoxy)triphenylbismuth and the triphenylbismuth-tert-butyl hydroperoxide system transform diethyl ether into ethoxyacetic aldehyde. The latter undergoes further conversions under these reaction conditions to give the corresponding hydroxyperoxide, ethoxyacetic acid, and bismuth(III) acylates.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 783–784, April, 1995.This work was financially supported by the Competition Center for Fundamental Natural Studies at Saint-Petersburg University (Grant No. 94-9.4-219).     

Cleavage of the carbon-carbon bond in α-glycols under the action of bismuth(v) derivatives

Di(tert-butylperoxy)triphenylbismuth and the triphenylbismuth-tert-butyl hydroperoxide system react with 2,3-dimethylbutane-2,3-diol, benzopinacol, butane-2,3-diol, and ethane-1,2-diol with the cleavage of the C−C bond of α-glycol to form carbonyl compounds. Both heterolytic (through formation of cyclic triphenylbismuth glycolate) and homolytic cleavage occur. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1212–1214, June, 1997.     

Synthesis of chiral organophosphorous ligands based on transformations of methyl 3,4-O-isopropylidene-l-threonate

Chiral organophosphorous compounds which are of interest as ligands for metallocomplex catalysts for enantioselective transformations were synthesized from methyl 3,4-O-isopropylidene-l-threonate. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp 393–396, February, 1997.     

Tris(polymethoxyphenyl)bismuth derivatives: Synthesis and reactivity

Tris-(polymethoxyphenyl)bismuth diacetate and dichloride derivatives react with C-nucleophiles in basic medium, as well as with N- and O-nucleophiles under copper catalysis to give good to high yields of the corresponding C-, N- and O-arylation products.     

Synthesis ofN-phenyl-substituted derivatives of morphine alkaloids

A method for the preparation ofN-phenyl-substituted morphine alkaloids by treatment of the correspondingN-nor derivatives with Ph₃Bi in the presence of Cu(OAc)₂ is proposed. 17-Nor-17-phenylthebaine thus obtained can serve as a convenient starting material for the preparation of otherN-phenyl-substituted alkaloids. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 595–598, March, 1999.     

Synthesis of novel 9-aryl and heteroarylpurine derivatives via copper mediated coupling reaction

A series of 9-(hetero)arylpurine derivatives has been prepared through N-arylation of 6-chloropurine with boronic acids in the presence of copper(II) acetate. Screening reaction conditions in terms of bases and solvents led to the successful coupling of a series of sterically demanding (hetero)arylboronic acids, never described so far. The coupling products were next readily converted into the target adenine derivatives. The described procedure provides easy access to original fragments for screening applications. Moreover these 9-aryl-6-chloropurine derivatives might be useful as intermediates for the preparation of purine derivatives with potential biological properties.     

Chemo-enzymatic preparation of chiral 3-aminopyrrolidine derivatives

A new simple method for the enantioselective enzymatic hydrolysis of N-protected D-asparagine esters suitable for the use on the preparative scale is presented. Due to major obstacles observed under conventional reaction conditions—racemization of the retained ester and a strong enzyme inactivation—a comparatively low pH together with an organic co-solvent had to be employed. Under these conditions, nearly all tested proteases demonstrated good activity and excellent enantioselectivity giving access to the corresponding d-esters and L-asparagines in high optical purities (>95% ee) and good chemical yields (>40%). From the unnatural d-asparagine derivative, sequential cyclization, selective deprotection and reduction yielded efficiently benzyl protected (R)-3-aminopyrrolidine, a homo-chiral building block utilized in numerous drug candidates.     

Synthesis of 2,2-dimethylchromans by the hydrogenation of 2,2-dimethyl-2H-chromenes

Summary 2,2-Dimethylchromans19–36 have been synthesized by the hydrogenation of 2,2-dimethyl-2H-chromenes1–18 in acetic acid solution in the presence of 10% Pd-C catalyst.Dedicated to Prof. Dr. W. Fleischhacker on the occasion of his 60th birthday     

Synthesis ofo-andm-carborane derivatives of [2,2]paracyclophane and abnormal Clemmensen reduction of ketones of the [2,2]paracyclophane and carborane series

Methods for the synthesis of [2,2]paracyclophane derivatives containingo- andm-carboranyl substituents in position 4, separated from the [2,2]paracyclophane system by one or two C atoms (alcohols and ketones) were developed. The Clemmensen reduction of a number of ketones of the [2,2]paracyclophane ando-carbonane series occurs abnormally. The reduction of 1-benzoyl-o-carboranes to the corresponding alcohols by zinc in ethanol in a neutral medium was performed for the first time. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1206–1211, June, 1997.     

Reaction of triphenylantimony and triphenylbismuth withtert-butyl peracetate

Triphenylantimony and triphenylbismuth diacetates, Ph₃M(OAc)₂ (M = Sb, Bi), were obtained in 50–94 % yields by the reaction of triphenylantimony and triphenylbismuth withtert-butyl peracetate in the presence of acetic acid or acetic anhydride (molar ratio 1 1 1) in toluene.tert-Butyl peracetate oxidizes Ph₃M into alkoxides, Ph₃M(OAc)OBu^t, which at the instant of formation are acylated with acetic acid or acetic anhydride to give the corresponding derivatives, Ph₃M(OAc)₂.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 964–967, May, 1995.This study was financially supported by the Russian Foundation for Basic Research (Grant 94-03-08846).     

Synthesis of Indolo phenothiazin-6-one derivatives

Summary 5H-Indolo[3,2-a]-6H-phenothiazin-6-one and its regioisomer 1H-Indolo[2,3-a]-6H-phenothiazin-6-one were prepared by the condensation of 2-aminobenzenethiol with carbazole-1, 4-dione or with isomeric mixture of bromo-carbazole-1,4-diones.

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Synthese von Indolo-Phenothiazin-6-on-Derivaten (Kurze Mitteilung)

Zusammenfassung 5H-Indolo[3,2-a]-6H-phenothiazin-6-on und sein Regioisomer 1H-Indolo[2,3-a]-6H-phenothiazin-6-on wurden mittels Kondensation von 2-Aminobenzolthiol mit Carbazol-1,4-dion oder mit einer isomeren Mischung von Bromcarbazol-1,4-dionen hergestellt.

     

trans-1-Sulfonylamino-2-isoborneolsulfonylaminocyclohexane derivatives: excellent chiral ligands for the catalytic enantioselective addition of organozinc reagents to ketones

The catalytic enantioselective addition of different organozinc reagents (such as alkyl and aryl derivatives or in situ generated aryl, allyl alkenyl, and alkynyl derivatives obtained through different transmetallation processes) to simple ketones has been accomplished by using titanium tetraisopropoxide and chiral ligands derived from substituted trans-1-sulfonylamino-2-isoborneolsulfonylaminocyclohexane, producing the corresponding tertiary alcohols with enantiomeric excesses (ee) up to >99 %. A simple and efficient procedure for the synthesis of the chiral ligands used in these reactions is described.     

Synthesis of cyasteronylthiocarbamate derivatives

Ecdysterone, cyasterone, ajugalactone, ajugasterone B, 22-acetylcyasterone, and turkesterone were isolated from leaves of Ajuga turkestanica (Labiatae). Their structures were established using spectral and chemical data. The 2,3,22-triacetate, 2,3,22-tri-O-p-iodobenzoylthiocarbamate, and 2-O-p-iodobenzoylthiocarbamate derivatives of cyasterone were synthesized. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 449–451, September–October, 2006.     

Synthesis of novel tryptamine and β-carboline derivatives via palladium-catalyzed reaction of bromotryptamine with organic boronic acids

New tryptamine 5, 7 and β-carboline derivatives 3 were preparated by palladium-catalyzed coupling reaction of 5-bromotryptamine 1 with aryl boronic acids. Dedicated to Professor András Lipták on his 70^th birthday.     

Synthesis of crowned phenoxazine derivatives

Summary 16H-2,5,8,11,14-Pentaoxacyclopentadecano[2,3-a]phenoxazin-16-one, its 17-bromo analogue and 16-hydroxy-2,5,8,11,14-pentaoxacyclopentadecanophenoxazine were prepared by the reaction of 1,4-quinone of benzo[15]crown-5 or its dibromide with 2-aminophenol. Dehalogenation of the bromophenoxazinone was also investigated.

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Synthese von Kronen-Phenoxazin-Derivaten (Kurze Mitt.)

Zusammenfassung 16H-2,5,8,11,14-Pentaoxacyclopentadecano[2,3-a]phenoxazin-16-on, sein Brom-Analog und 16-Hydroxy-pentaoxacyclopentadecanophenoxazin wurden mittels der Reaktion des 1,4-Chinons von Benzo[15]krone-5 oder dessen Dibromid mit 2-Aminophenol hergestellt. Die Dehalogenierung von Bromphenoxazinon wurde ebenfalls untersucht.

     

Synthesis of phosphorus (silicon,tin)-containing derivatives of mercaptoketenes and some of their properties

Some newS-phosphorylated,S-silylated, andS-stannylated derivatives of -mercaptoketones were obtained. The reactions of some of these compounds induced by the temperature and by molecular oxygen as well as the phosphorylation of the Si- and Sn-containing derivatives were studied.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 353–357, February, 1995.     

Synthesis of quinoxalines fused with triterpenes,ursolic acid and betulin derivatives

Oxidation of triterpenoids methyl ursonate, acetylbetulone, and allobetulone with atmospheric oxygen in the presence of Bu^tOK in Bu^tOH afforded the corresponding 2,3-diketo derivatives in 90-97% yields. These derivatives exist predominantly as tautomers containing the enolized keto group at the C(2) atom. Their reactions with o-phenylenediamine gave rise to the corresponding quinoxalines in 85-95% yields.     

N- and O-arylation with triphenylantimony ortho-phenylenedioxides

2,2,2-Triphenyl-1,3,2-benzodioxastibolanes react with alcohols, phenols, and amines in the presence of copper salts to give the corresponding O- and N-phenyl derivatives. Cyclic Sb^V dialkoxide containing an electron-withdrawing nitro group in the dioxastibolane fragment is most reactive in N-phenylation of primary and secondary amines. Organoantimony analogs containing electron-donating groups are more efficient in O-phenylation of primary and secondary alcohols and phenols.     

钯催化羰基衍生物α位的芳基化反应及其在天然产物合成中的应用

对钯催化羰基衍生物α位的芳基化反应的研究进展做了论述, 重点介绍了酮羰基化合物α-芳基化反应、酰胺类化合物α-芳基化反应和酯类化合物α-芳基化反应的研究进展. 此外, 对钯催化酮α-芳基化反应在γ-Lycorane合成中的应用和钯催化酰胺α-芳基化反应在Cherylline, Latifine及Physovenine等天然产物合成中的应用也进行了专门介绍.