α-Thioureidoalkylation of urea heteroanalogs

α-Thioureidoalkylation of urea heteroanalogs such as thiosemicarbazide, amino-guanidine, sulfamide, and sulfonamides with 4,5-dihydroxyimidazolidine-2-thiones has been studied. Previously unknown 4,5-bis[thiosemicarbazido(guanidinoamino)]imidazolidine-2-thiones, 5,7-dialkylperhydroimidazo[4,5- e][1,2,4]triazine-3,6-dithiones, 4,6-diethyl-5(3H)-thioxotetrahydro-1 H-imidazo[4,5- c][1,2,5]thiadiazole 2,2-dioxide, and 1,3-dialkyl-4-[guanidinoimino(arylsulfonylimino)]imidazolidine-2-thiones have been synthesized.     

Hydrazones ofα-pyrazolidinylacetoacetic ester

The p-nitrophenylhydrazones and acetylhydrazones of trans--(1-acetyl-2-phenyl-3-methyl-5-pyrazolidinyl)-acetoacetic ester have been obtained in the form of a mixture of diastereomeric pairs of syn-isomers. Individual diastereomeric pairs that have been isolated do not undergo any tautomeric conversions in nonpolar solvents. Heterocyclization of these hydrazones is difficult.M. V. Lomonosov Moscow State University, Moscow 119899. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 311–320, March, 1998.     

Synthesis ofα-substitutedα-amino acids by the alkylation of 5-oxazolinone derivatives

Methods have been developed for the alkylation of 5-oxazolinone derivatives in DMF in the presence of K₂CO₃, KOH, or diisopropylethylamine and a phase transfer catalyst as well as for the preparation of-methyl-phenylalanine,-methylalanine,-methylalanine, and the methyl ester of N-benzoyl--methylalanine. Increasing the initial concentration of the starting 5-oxazolinone in the reaction mixture leads to a sharp drop in the yield of reaction products due to side condensation reactions. The reaction of 2-phenyl-4-benzyl-5- oxazolinone with ethyl iodide gave a dimer namely, 3-(benzoylamino)-3,5-dibenzylpyrrolidine-2,4-dione.Latvian Institute of Organic Chemistry, LV-1006 Riga. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 829–833, June, 1994. Original article submitted January 21, 1994.     

Conformation of α,α,α′-Trisubstituted Cyclododecanone

Ten α,α,α′-trisubstituted cyclododecanones were synthesized and characterized by elemental analyses, infrared, 1^H NMR and 13^C NMR spectra, and X-ray diffraction. NMR data could not give conformational information clearly, but some of their ring skeleton conformations of cyclododecanone moiety were showed to remain the unchanged [3333]-2-one conformation with little distortion, while the others were changed to the [3324]-2-one conformation in their crystal structures. These are consistent with the results of molecular mechanics calculation with Sybyl 6.9 software and Tripos force field, and semi-empirical quantum calculation with AM 1 method in Gaussian 98 software. Two geminal substituting groups are located at α-corner carbon atom, and the third group is at α-side-exo carbon atom in both conformations. Both [3333]-2-one and [3324]-2-one conformations are present in a dynamic equilibrium in the solution, but only one preferred conformation exists in the crystal solid.     

Aryl-ONN-azoxy-α,α-dinitroalkanes and some of their derivatives

Previously unknownN-dinitroalkyl-NNO-azoxybenzenes have been prepared (by nitration ofN-(-hydroximino) alkyl-NNO-azoxybenzenes) and transformed to some derivatives.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1972–1975, November, 1994     

Formulation ofα-linolenic acid microemulsion free of co-surfactant

<正>A novel class ofα-linolenic acid-in-water microemulsion free of co-surfactant was investigated as potential food delivery systems.Rough demarcation within the transparent region was deduced from the results of conductivity and polarizing optical microscopy.The microemulsion mean hydrodynamic diameter and characterization were determined by dynamic light scattering and negative-staining TEM.The location of ALA molecules in the microemulsion formulations was determined by ~1H NMR spectroscopy.     

Thermogravimetrical investigations of the dealkoxycarbonylation of N-acyl-α-triphenylphosphonioglycinates

Thermogravimetrical experiments revealed that immediately after the endothermic process of the melting of N-acyl-α-triphenylphosphonioglycinates 1, an exothermic demethoxycarbonylation of phosphonioglycinates commenced, accompanied by the release of CO₂. The residues contained the corresponding N-acylaminomethyltriphenylphosphonium salts 2 (18.3–49.5%), methyltriphenylphosphonium salts 7 (21.8–67.9%), and the corresponding 1,2-di(N-acylamino)fumaric acid dimethyl ester 6 (2.1–26.0%). When the reaction was carried out in the presence of Ph₃P and the corresponding triphenylphosphine hydrobromide, hydroiodide, or tetrafluoroborate, N-acyl-α-triphenylphosphoniumglycinate bromides and iodides 1a–f underwent demethoxycarbonylation to form the corresponding N-acylaminomethyltriphenylphosphonium salts 2a–f at 95–130 °C in good to excellent yields (79–100%). On the other hand, tetrafluoroborates 1g–i underwent corresponding reactions at about 170–175 °C to give phosphonium tetrafluoroborates 2g–i in much lower yields (34–67%). Plausible mechanisms of the investigated reaction are discussed. It was also demonstrated that the obtained crude α-(N-acylamino)alkyltriphenylphosphonium salts 2 could be applied as valuable α-amidoalkylating agents in spite of their contamination with inert methyltriphenylphosphonium salts 7.     

Polymerization of p -triethylstannyl-α-methylstyrene

Summary Polymerization of p-triethylstannyl--methylstyrene was studied under 6000 atm pressure in the presence of various initiators. Polymers were isolated and their elemental composition and properties were determined.     

Conversions of 2-α-chloroalkylbenzimidazoles

Upon interaction with caustic in a DMSO medium, 2-chloromethylbenzimidazoles are subjected to cyclodimerization, forming 5H,12H-pyrazino[1,2-a:4,5-a]bis-benzimidazoles; in the presence of nucleophiles (ammonia, amines, anions of -diketones), under the indicated conditions, the products are the corresponding substituted amines or derivatives of pyrrolo[1,2a]benzimidazole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 664–672, May, 1993.     

α-Aminoxylation of Ketones and β-Chloro-α-aminoxylation of Enones with TEMPO and Chlorocatecholborane

Oxidation of various cyclic and acyclic ketones under mild conditions with chlorocatecholborane, a bulky pyridine base, and TEMPO to the corresponding α-aminoxylated products in good to excellent yields (52-99%) is described. For enones as substrates, products of a β-chloro-α-aminoxylation are obtained (70-89%).     

Synthesis of O-glycosylα-aryl nitrones

<正>α-Aryl nitrone are one of the most useful kinds of nitrones and have been extensively explored in recent years.However,the sugar moieties have not been introduced into these molecules before.We presented here an efficient synthesis ofα-aryl nitrone Oglycosides via condensation of N-substituted hydroxylamine and aryl aldehydes glycosides in benzene.     

Microbiologically-assisted hemisynthesis of 1α-hydroxydrimenol

The hemisynthesis of 1α-hydroxydrimenol has been selected to illustrate a synthetic route involving an initial microbial 3β-hydroxylation of a drimenol derivative followed by a functionalization transfer to position 1α, thus generating a new potentially bioactive hydroxylated terpenic compound. Several methods have been investigated for the protection and the regeneration of the 7,8-double bond of drimenyl derivatives.     

α-Tosyloxylation of fluorosubstituted β-diketones

The interaction of fluorinated -diketones with [hydroxy(tosyloxy)iodo]benzene leads to -tosyloxy--diketones existing in the form of stable hydrates.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 541–542, March, 1994.     

A fluoro analogue of UDP-α-D-glucuronic acid is an inhibitor of UDP-α-D-apiose/UDP-α-D-xylose synthase

UDP-2F-glucuronic acid was synthesized and analyzed as a mechanistic probe to investigate the ring contraction step catalyzed by UDP-d-apiose/UDP-d-xylose synthase (AXS).     

Synthesis of Derivatives of ω-Isocyanato-α-methylamino, ω-Ureido-α-methylamino, and Nα-Methyl-α, ω-diamino Acids

 Homochiral N^α-methyl-2,3-diaminopropionic and N^α-methyl-2,4-diaminobutyric acid derivatives 8a,b were obtained via a stereoconservative four-step synthesis starting from hexafluoroacetone protected L-aspartic and L-glutamic acid 2a,b, respectively. Hexafluoroacetone protected ω-isocyanato-α-methylamino acids 4a,b– the key intermediates of the synthesis – are versatile building blocks for amino acid and peptide modification and promising candidates for combinatorial chemistry. Upon reaction with alcohols, compounds 4 give activated N ^ω-urethane protected ω-amino-α-methylamino acid derivatives 5–7; upon reaction with amines, ω-ureido-α-methylamino acid derivatives 10–12 and 3-methylamino-pyrrolidin-2-ones 13 are available.     

Synthesis of alkyl-α,α-dimethylcyclopropanemethanols and alkylcyclopropyl methyl ketones

Russian Chemical Bulletin -     

Synthesis and Crystal Structure of β-Amino-α-Phenyl-α-Ferrocenylethanol

β-Amino-α-phenyl-α-ferrocenylethanol, FcC(OH)(Ph)CH₂NH₂ was prepared by the reduction of cyanohydrin trimethylsilyl ether of benzoylferrocene with lithium aluminum hydride. This new compound was characterized by elemental analysis, IR and ¹H NMR spectroscopy. The structure was also confirmed by a single crystal X-ray study. The compound crystallizes in monoclinic P2₁/c space group with unit cell dimensions: a = 12.5906(17), b = 5.9636(8), c = 19.8320(3) Å, β = 102.047(2)^∘, V = 1456.3(3) ų, Z = 4. The structure exhibits intra- and inter-molecular hydrogen bonding of the type N—H⋅ < eqid1 > ⋅O and O—H⋅ < eqid2 > ⋅N, respectively. The pattern of the inter-molecular hydrogen bonding interaction contains a 10-atom ring with two donors and two acceptors, showing a dimeric crystal packing.     

Ionic liquid-promoted Wagner-Meerwein rearrangement of 16α,17α-epoxyandrostanes and 16α,17α-epoxyestranes

Ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim](+)[PF(6)](-)) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim](+)[BF(4)](-)) were found to promote an unusual Wagner-Meerwein rearrangement of steroidal 16α,17α-epoxides leading to unnatural 13-epi-18-nor-16-one derivatives as the main products. These compounds were isolated in good to excellent yields. 16α-Hydroxy-Δ(13)-18-norsteroids, the results of the usual rearrangement, were obtained as minor components of the reaction mixtures. The ionic liquid [bmim](+)[PF(6)](-) was shown to induce C-ring aromatization of 16α,17α-epoxyestranes due to the formation of HF, the hydrolysis product of [PF(6)](-). Increasing amounts of HF and [PO(2)F(2)](-) were detected by (19)F and (31)P NMR when the ionic liquid was reused. The structures of the steroidal products, 16-oxo-18-nor-13α-steroid derivatives, 16α-hydroxy-Δ(13)-18-norsteroids, and C-aromatic compounds were determined by two-dimensional NMR techniques and high-resolution mass spectrometry (HRMS). The ionic liquids were recirculated efficiently.