Synthesis of <Emphasis Type="Italic">N</Emphasis>-(2-chloroethyl)glycine and -<Emphasis Type="SmallCaps">DL</Emphasis>-alanine esters

Two methods for the synthesis of N-(2-chloroethyl)glycine and-DL-alanine esters are proposed: 1) reductive amination of the C=O group of glyoxilic or pyruvic acids upon treatment with 2-chloroethylamine and sodium cyanoborohydride in methanol and 2) alkylation of 2-chloroethylamine with α-haloalkanoic acid esters in K₂CO₃-MeCN two-phase system. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2372–2374, December, 2007.     

Reactions of 2-(4,5-dihydro-3-furyl)-1,3-diphenyl-1,3-diaza-2λ<Superscript>3</Superscript>-phospholidine and 4,5-dihydro-3-furylphosphonous diamides with nitrile imines

Reactions of 2-(4,5-dihydro-3-furyl)-1,3-diphenyl-1,3-diaza-2λ³-phospholidine (1) with nitrile imines are multistep processes involving cleavage of one P-N bond of the diazaphospholidine ring to form substituted 5-(2-chloroethyl)-4-(N,N′-diphenylethylenediamino)-1,4-dihydro-1,2,4λ⁵-diazaphosphorines 4 as final products. Analogs of phospholidine 1, namely, 4,5-dihydro-3-furylphosphonous dipiperidide and dimorpholide, react with C,N-diphenylnitrile imine with retention of both P-N bonds to give 5-(2-hydroxyethyl)-1,2,4-diazaphosphorinium chlorides. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1590–1593, July, 2005.     

Alkylation of salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides with alkyl halides and dimethyl sulfate

Salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides, RCH(OH)CH₂N(O)=NO⁻ M⁺ (R=Me, Prⁱ, or Bu^t; and M=Li, Na, K, Ag, NH₄, or Me₄N), were prepared. Their alkylation with alkyl halides R′X (X=Cl, Br, or I) and dimethyl sulfate was studied. Generally, alkylation afforded mixtures ofN-(β-hydroxyalkyl)-N′-alkoxydiazeneN-oxides RCH(OH)CH₂N(O)=NOR′ andO-alkyl-N-(β-hydroxyalkyl)-N-nitrosohydroxylamines RCH(OH)CH₂N(NO)OR′. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1996–2001, October, 1998.     

Efficient and scalable process for the synthesis of antihypercholesterolemic drug ezetimibe

An efficient and scalable process for the synthesis of antihypercholesterolemic drug ezetimibe through chiral Evans auxiliary (S)-4-phenyl-2-oxazolidinone is described. The key steps in this process are the condensation of (S)-3-(5-(4-fluorophenyl)-5,5-dimethoxypentanoyl)-4-phenyloxazolidin-2-one and N-(4-((tert-butyldimethylsilyl)oxy)benzylidene)-4-fluoroaniline, and the stereoselective reduction of ezetimibe-ketone with NaBH₄/I₂, which is first applied in the synthesis of ezetimibe. The process is concise, mild, easy to operate, and highly stereoselective (99.6% of de value of ezetimibe). In addition, three diastereomers of ezetimibe are synthesized and served as the references in quality control of the product.     

Synthesis ofN-(3-azido-2-nitroxypropyl)-,N-(2,3-diazidopropyl)-, andN-(2-azido-3-methoxypropyl)-N-alkylnitramines

N-(3-Azido-2-nitroxypropyl)-N-alkylnitramines andN-(2,3-diazidopropyl)-N-alkylnitramines were prepared by nitration and azidation ofN-alkyl-N-(2-hydroxy-3-chloropropyl)sulfamates andN-(3-azido-2-hydroxypropyl)-N-alkylsulfamates. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 206–208, January, 1999.     

Vibrational frequencies and force constants of N2O4 in complexes with molecules of different solvents determined by Raman spectra andAb initio calculation

The Raman spectra of N₂O₄ solutions in organic solvents have been recorded. The frequencies ofv ₁,v ₂, andv ₃ bands of N₂O₄ increase with increasing solvent electron-donor properties. Especially large changes ofv ₃ N-N stretching band have been observed (254.5 cm^–1 in n-hexane, 276.5 cm^–1 in 1,4-dioxane). The ab initio calculations have shown that the interaction between N₂O₄ and electron-donor molecules causes an increase of N-N and N-O stretching and O-N-O bending force constants of N₂O₄ in agreement with the results of Raman study.     

Synthesis and structures of complexes ofN-2-nitroxyethylpicolinamide and 2-(2-pyridyl)-2-oxazoline with PdCl2

The reaction ofN,N′-bis(2-nitroxyethyl)pyridine-2,6-dicarboxamide with PdCl₂ afforded previously unknowncis-(N-2-nitroxyethylpicolinamide-N,N′)dichloropalladium(II) andcis-[2-(2-pyridyl)-2-oxazoline-N,N′]dichloropalladium(II), which were isolated as a cocrystallizate of the molecular compounds. Its structure was established by X-ray diffraction analysis. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1604–1606, August, 1999.     

Claisen aromatic amino rearrangement in the series of fluorinated anilines

The effect ofmeta-substituents in the aromatic ring on the route of Claisen rearrangement ofN-(pent-3-en-2-yl)-3-fluoro(or 3-trifluoromethyl, 3,4-difluoro)anilines induced by ZnCl₂ was investigated. The formation of two possibleortho-alkenylated reaction products was observed. The ratio of these isomers depends on the nature of the acid catalyst. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 188–190, January, 1998.     

OH−-induced β-elimination reactions with 1-(2-Xethyl)-4-nitrobenzene substrates in solvent mixture H2O/CH3CN and H2O/DMSO: Reactivity and mechanism

The behaviour of 1-(2-bromoethyl) 4-nitrobenzene (1), N,N,N-triethyl-2-(4-nitrophenyl)ethanaminium bromide (2) and N,N-diethyl-N-[2-(4-nitrophenyl)ethyl]octan-1-aminium bromide (3) in the OH⁻-induced elimination reactions with formation of 1-nitro-4-vinylbenzene in mixtures of DMSO/H₂O or CH₃CN/H₂O has been investigated. With all three substrates an increase in dipolar aprotic solvent content implies a limited increase of the second-order rate constant k _OH up to ≅605, and then an exponential increase is observed. The variation of activation parameters ΔH ^# and dGS ^#, measured in DMSO/H₂O mixtures, is parallel for 1 and 2. This similar behaviour of 1 and 2 with respect to variation in solvent composition is evidence that it is not possible to use this technique of solvent effect for the mechanistic diagnosis of elimination reactions.     

Reactions of N,N-(dialkyl)arylthioacetamides with dialkyl acetylenedicarboxylates

2-(Alkoxycarbonylmethylidene)-4-aryl-5-(dialkylamino)thiophen-3(2H)-ones were synthesized by condensation of N,N-(dialkyl)arylthioacetamides with dialkyl acetylenedicarboxylates. Intermediate substituted vinylic sulfides were isolated. When heated or in the presence of an acid or a base, they undergo cyclization into thiophenes.     

Cyclization ofN-acetyl-ortho-cycloalkenylanilines on treatment with bromine andN-bromosuccinimide

The reaction ofN-acetyl-2-(cyclohex-1-enyl)aniline with Br₂ orN-bromsuccinimide at 20°C is accompanied by intramolecular cyclization to give brominated 3,1-benzoxazines or 4-acetyl-(3-bromo-5-methyl-1,2,3,3a,4,8b-hexahydrocyclopenta[b]indole. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 118–120, January, 2000.     

Cyclization ofN-acetyl-ortho-cycloalkenylanilines on treatment with bromine andN-bromosuccinimide

The reaction ofN-acetyl-2-(cyclohex-1-enyl)aniline with Br₂ orN-bromsuccinimide at 20°C is accompanied by intramolecular cyclization to give brominated 3,1-benzoxazines or 4-acetyl-(3-bromo-5-methyl-1,2,3,3a,4,8b-hexahydrocyclopenta[b]indole. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 118–120, January, 2000.     

The influence of substituents (R) at the C carbon on bonding properties of thiosemicarbazones {RC(H)N-NH–C(S)–NH2} in palladium(II) complexes

Reactions of the trans-PdCl₂(PPh₃)₂ precursor with furan-2-carbaldehyde thiosemicarbazone (Hftsc) and thiophene-2-carbaldehyde thiosemicarbazone (Httsc), in 1:1 molar ratios in the presence of Et₃N base, removed one Cl and one PPh₃ group from the Pd^II center, and yielded the complexes [Pd(η²-N³,S-ftsc)(PPh₃)Cl] (1) and [Pd(η²-N³,S-ttsc)(PPh₃)Cl] (2), respectively. However, when a 1:2 molar ratio (M:L) was used, both Cl and PPh₃ ligands were removed, yielding the complexes trans-[Pd(η²-N³,S-ftsc)₂] (3) and trans-[Pd(η²-N³,S-ttsc)₂] (4). Complexes 1–4 have been characterized with the help of analytical data, spectroscopic techniques (IR, ¹H and ³¹P NMR) and single crystal X-ray crystallography. The thiosemicarbazone ligands behave as uninegative N³,S-chelating ligands in complexes 1–4. In contrast, pyrrole-2-carbaldehyde thiosemicarbazone (H₂ptsc) and salicylaldehyde thiosemicarbazone (H₂stsc) invariably formed the complexes [Pd(η³-N⁴,N³,S-ptsc)(PPh₃)] (5) and [Pd(η³–O, N³,S-stsc)(PPh₃)] (6), respectively, and the ligands acted as binegative tridentate donors (N⁴, N³, S, 5; O, N³, S, 6).     

Co(III) complexes of Me-salpn and Me-salbn and the ring size effect on the coordination modes and electrochemical properties: The crystal structures of trans-[Co(Me-salpn)(py)2]PF6 and cis-α-[Co(Me-salbn)(4-Mepy)2]BPh4 · 4-Mepy

The synthesis and characterization of a series of cobalt(III) complexes of the general type [Co(N₂O₂)(L₂)]⁺ are described. The N₂O₂ Schiff base ligands used are Me-salpn (H₂Me-salpn = N,N′-bis(methylsalicylidene)-1,3-propylenediamine) (1–3) and Me-salbn (H₂Me-salbn = N,N′-bis(methylsalicylidene)-1,4-butylenediamine) (4–5). The two ancillary ligands L include: pyridine (py) 1, 3-metheylpyridine (3-Mepy) 2, 1-methylimidazole (1-MeIm) 3, 4-methylpyridine (4-Mepy) 4 and pyridine (py) 5. These complexes have been characterized by elemental analyses, IR, UV–Vis, and ¹H NMR spectroscopy. The crystal structures of trans-[Co^III(Me-salpn)(py)₂]PF₆, 1, and cis-α-[Co^III(Me-salbn)(4-Mepy)₂]BPh₄ · 4-Mepy, 4, have been determined by X-ray diffraction. Examination of the solution and crystalline structures revealed that the outer coordination sphere of the complexes exerts a noticeable influence on the inner coordination sphere of the Co(III) ion. The electrochemical reduction of these complexes at a glassy carbon electrode in acetonitrile solution indicates that the first reduction process corresponding to Co^III–Co^II is electrochemically irreversible, which is accompanied by the dissociation of the axial (R-py)–cobalt bonds. It has also been observed that the Co(III) state is stabilized with increasing the flexibility of the ligand environment.     

Synthesis,stereochemistry, and spectroscopic characterization of [Rh(η4-cod){(R)-2-(X-benzaldimine)-2-phenylethanol-κ 2 N,O}](acetate) (X = H; 2,4-dimethoxy)

Condensation of X-benzaldehyde with (R)-2-amino-2-phenylethanol gives the enantiopure Schiff bases (R)-2-(X-benzaldimine)-2-phenylethanol (X?=?H, HL1; 2,4-dimethoxy, HL2). The Schiff bases coordinate with dinuclear [Rh(η⁴-cod)(µ-O₂CCH₃)]₂ to afford the cationic complexes [Rh(η⁴-cod){(R)-2-(benzaldimine)-2-phenylethanol-κ ² N,O}](acetate), [Rh(η⁴-cod)(HL1)](ac) (1) and [Rh(η⁴-cod){(R)-2-(2,4-dimethoxy-benzaldimine)-2-phenylethanol-κ ² N,O}](acetate), [Rh(η⁴-cod)(HL2)](ac) (2), respectively. The Schiff bases and complexes are isolated as solids in good yields and characterized by elemental analysis, IR, UV-Vis, ¹H/¹³C-NMR, mass spectroscopy, and polarimetry.     

Reactions of benzimidazole-2-carbaldehyde with enamines

Benzimidazole-2-carbaldehyde reacts with 1-morpholinocyclohexene, 1-morpholinocyclopentene, and aminocrotonic ester upon heating to form 4a,11-dimorpholino-1,2,3,4,11,11a-hexahydro-4aH-indolo[1,2-a]benzimidazole, 2-(2-morpholino-4,5-dihydrofulvenyl)benzimidazole, and 4-(benzimidazol-2-yl)-3,5-diethoxycarbonyl-2,6-dimethyl-1,4-dihydropyridine, respectively. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 566–571, March, 1999.     

N-(2-Thenyl)derivatives of aminoalkyltriethoxysilanes,-silatranes and 2,2-dimethyl-1,3-dioxa-6-aza-silacyclooctane

The reactions of aminoalkylethoxysilanes and 2,2-dimethyl-1,3-dioxa-6-aza-2-silacyclooctane with 2-(chlormethyl)thiophene and its 5-chloroderivative lead to the correspondingN-(2-thenyl) derivatives. TheN-methyl-N-(2-thenyl)aminomethyltriethoxysilane and 5-chlorothyenyl derivative formed are converted by triethanolamine into silatranes.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 384–386, February, 1995.     

Reaction of vinyloxyalkylamines with mercaptoacetic acid

N-[2(3)-Hydroxyalkylj-4-thiazolidinones have been synthesized by the reaction of 2(3)-vinyloxyalkylamines with mercaptoacetic acid in 24–69 % yield. The structure of the compounds obtained was supported by (R and¹H NMR spectroscopic data.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 677–679, March, 1996.     

Synthesis and structure of <Emphasis Type="Italic">N</Emphasis>-(2-(1-adamantyl)-2-hydroxyethyl)cytisine diastereomers

Diastereomers of N-(2-(1-adamantyl)-2-hydroxyethyl)cytisine were synthesized by reduction of N-(2-(1-adamantyl)-2-oxoethyl)cytisine with NaBH₄. Their structures were established using x-ray structure analysis. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 244–247, May–June, 2007.     

g-C3N4/Bi2O2CO32D纳米片复合材料的制备及可见光催化性能研究

采用自组装和化学沉淀法分别制得两种可见光驱动复合材料石墨相氮化碳/碳酸氧铋(g-C_3N_4/Bi_2O_2CO_3).采用X射线衍射光谱(XRD),紫外可见光谱、扫描电镜(SEM)、N_2吸附、电化学阻抗谱(EIS)和X射线光电子能谱(XPS)等分析手段对制备的催化剂进行了表征.结果表明,制备方法对纳米复合材料的晶相、形态及光学性能没有影响,但是影响g-C_3N_4和Bi_2O_2CO_3之间的相互作用力,导致光生电子-空穴对的分离速率存在显著差异.以可见光驱动苯酚和罗丹明B的降解实验为探针反应检测催化剂的光催化性能.实验结果表明自组装法得到的异质结催化剂中相互作用力更强,催化效果最高.O_2-是罗丹明B降解反应的主要活性物种,染料的光敏化、Bi_2O_2CO_3与g-C_3N_4综合效应,导致光生载流子电荷分离效率更高.