I. Ya. Mainagashev

Preparation and nitration of allobetulin seco-derivatives

2-Nitro-derivatives of allobetulone were prepared by reaction of allobetulin with nitric acid. 2β-Aminoallobetulin was synthesized by reduction of 2-nitrobetulone with LiAlH4. The corresponding allobetulin seco-derivatives were obtained via oxidation by H2O2 in the presence of K2CO3 of 2-nitroallobetulone and cleavage of 2,2-dinitroallobetulone by K2CO3 in H2O:THF.

Reduction of 2,3-Seco-28-oxo-19β,28-epoxy-18α-olean-2,3-dicarboxylic acid and its cyclic anhydride

Reduced derivatives of 2,3-seco-28-oxo-19β,28-epoxy-18α-olean-2,3-dicarboxylic acid and its cyclic anhydride were prepared. Reduction of the starting 2,3-secodicarboxylic acid by NaBH4–I2 produced the 2,3-seco-2,3-dihydroxy derivative. Reaction of the starting anhydride with LiAlH4 gave the 2,3-seco2,3,19β,28-tetrahydroxy derivative. Cyclization using acidic reagents of the 2,3-seco-2,3-hydroxy- and 2,3seco-2,3,19β,28-tetrahydroxy derivatives gave the corresponding cyclic ethers containing an oxepane ring. The anhydride ring was reduced by NaBH4 to the corresponding ε-lactone, the structure of which was confirmed by an x-ray crystal structure.

Antitumor Activity of Amides of Dihydrobetulonic Acid in vitro and in vivo

Amides containing homopiperidine and piperazine cycles were synthesized from dihydrobetulonic acid obtained by the oxidation of dihydrobetulin. All substances were shown to have a high antitumor activity (CCID50 = 3.5–36.2 μM) in vitro in lymphoid (CEM-13, U-937) and monocytic (MT-4) human cell lines. Amides containing the methyl- and ethylpiperazine residues do not influence the viability of Lung Lewis Carcinoma cells in culture and do not have a significant effect on its transplants in C57BL/6 mice. However, these amides efficiently inhibit the development of metastases in lungs of these mice. The antimetastatic activity of the studied amides increases with changing the methyl by ethyl aliphatic residue in the piperazine cycle.

Synthesis of 1-phenyl-6H-anthra[1,9-b,c]furan-6-one (furanoanthrone) derivatives by the reaction of 1-acyloxy-9,10-anthraquinones with benzyl cyanide

The reactions of various I-acyloxyanthraquinones with benzyl cyanide in DMSO in the presence of K2CO3 were studied. 1-Phenyl-6H-anthra[1,9-b,c]furan-6-one derivatives are formed as the main reaction products. In the case of unsubstituted I-acyloxyanthraquinones, 1-phenyl-6H-anthra[1,9-b,c[furan-6-one and I-phenylanthra[1,9-b,clpyran-2,l-dione were isolated. It was shown that furanoanthrones can be synthesized in two steps via the corresponding pyronoanthrones.

Chemistry and Dynamics of Interaction of Nucleosides with Pentafluoropyridine

Interaction of pentafluoropyridine with hydroxyl groups of thymidine, uridine, adenosine, and deoxyadenosine at room temperature leads to the formation of aryl ethers of nucleosides with a high yield. Under severe conditions, one more tetrafluoropyridine residue is attached to pyrimidine fragments of T and U, while purine heterocycle in A remains intact. Nucleoside derivatives are formed with a quantitative yield and can be used in situ as intermediates for, as an example, molecular design of arene analogs of nucleic acids. The reaction with thymidine is a successive-parallel process, the limited stage being arylation of the secondary hydroxyl group. The presence of the vicinal hydroxyl group in pentose results in the opposite rate ratio of the formation of primary and secondary tetrafluoropyridyl ethers of adenine and uridine.

Polynucleotides and Their Components in the Processes of Aromatic Nucleophilic Substitution: I. Chemistry and Dynamics of Nucleotide Arylation with Pentafluoropyridine; Obtaining of Synthons for Molecular Design of Nucleic Acid Analogues

Pentafluoropyridine reacts with thymidine, adenosine, and uridine hydroxy groups to give quantitative yields of the corresponding nucleoside di- and triaryl ethers. The nucleophilic substitution reactions proceed successively and in parallel, with the slowest step being the nucleophilic substitution of the nucleoside secondary hydroxyls. The resulting ethers contain tetrafluoropyridyl moieties, which could be smoothly modified by nucleophilic substitution of fluorine atoms. The ethers are useful intermediate synthons (both isolated and in situ) for molecular design of oligonucleotide analogues.

Photochemical and thermal rearrangements of 2-arylamino-1-(4-tert-butylphenoxy)-9,10-anthraquinones

Photochemical transformations of 2-arylamino-1-(4-tert-butylphenoxy)-9,10-anthraquinones involve migration of thetert-butylphenyl group either to theperi-located carbonyl oxygen to give 2-arylamino-9-(4-tert-butylphenoxy)-1,10-anthraquinones or to the nitrogen atom to give 2-aryl(4-tert-butylphenyl)amino-1-hydroxy-9,10-anthraquinones (typical products of the Smiles rearrangement).

Photolysis of 1,2-anthraquinone diazide in aromatic hydrocarbons

It has been determined that the main products of photolysis of 1,2-anthraquinone diazide in benzene, toluene, anisole, nitrobenzene, and pyridine are the corresponding 1-hydroxy-2-arylanthraquinones that form as a mixture ofortho, meta, andpara isomers with significant content of themeta isomer (40–55%).

Polyfunctional molecules in processes of aromatic nucleophilic substitution 3. Pentaf luoropyridines as scaffolds for synthesis of liquid-phase combinatorial libraries based on S N Ar processes

A possibility of using polyfluorinated pyridines as multiply modified molecules, i.e., scaffolds, in processes of aromatic nucleophilic substitution (SNAr) for the synthesis of liquid-phase combinatorial libraries was studied. The real and “virtual” combinatorial libraries of diaryl ethers were synthesized by the reactions of pentafluoropyridine with phenol and its derivatives. Some criteria for the estimation of the quality of the libraries were formulated. A rational methodology for the preparation of representative combinatorial mixtures on the basis of processes of the SNAr type in polyfluorinated arenes was proposed. The libraries can be used in highly efficient biological screening of low-molecular-weight regulators of transferase functioning.

Polynucleotides and Their Components in the Processes of Aromatic Nucleophilic Substitution: II.1 Nucleophilic Modification of 3′,5′-Bis-O- (α,β,α′,β′-tetrafluoropyrid-γ-yl)thymidine

The interaction of 3′,5′-bis-O-(α,β,α′,β′-tetrafluoropyrid-γ-yl)thymidine with various nucleophilic reagents was studied to evaluate the possibility of molecular design of new types of nucleic acid analogues using SNAr reactions. The reactions with morpholine and sodium azide led to the introduction of one and two nucleophilic residues into each of the polyfluorinated pyridine rings. The nucleophilic polycondensation with bifunctional reagents ethylenediamine and hexamethylenediamine depended on the nature of nucleophile and reaction conditions and resulted in the formation of supramolecules containing about five or more than 20 pyrimidine bases.