Thiocarbamoylation of amine-containing compounds

Thiocarbamoylation of 5-aminosalicylic acid with tetramethylthiuram disulfide afforded 5-(N′,N′-dimethylthioureido)salicyclic acid. Treatment of the latter with mineral acids or Ac₂O gave 5-isothiocyanatosalicylic acid whose reaction with ethanolamine yielded 5-[N′-(2-hydroxyethyl)thioureido]salicylic acid. The latter underwent cyclization under the action of TsOH to form 5-(2-thiazolin-2-ylamino)salicylic acid. For Part 2, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2315–2318, December, 1999.     

Deamination of Some N-Amino Nitrogen Heterocycles Using Preyssler’s Anion

Summary. Some N-aminotriazines and -triazoles were treated with Preyssler’s anion as catalyst in acetic acid to afford the corresponding deaminated triazines and triazoles. The reaction is suggested to proceed via formation of N-nitrosamines with subsequent N–NO bond cleavage.     

Three-component one-pot synthesis of fused uracils – pyrano[2,3-d]‐pyrimidine-2,4-diones

5-Arylidene-N,N-dimethylbarbituric acids undergo smooth hetero-Diels-Alder reactions with enol ethers to afford cis and trans diastereoisomers of 7-alkoxy-5-aryl-2H-pyrano[2,3-d]pyrimidine-2,4-diones in excellent yields (84–95%). Cycloadducts with cis-configuration were the major products. Three-component one-pot reactions of N,N-dimethylbarbituric acid, aromatic and heteroaromatic aldehydes, and enol ethers in the presence of piperidine gave uracils also in very good yields (87–95%). The structure of the cycloadducts is discussed in terms of configuration and preferred conformation. Correspondence: Aleksandra Pałasz, Department of Organic Chemistry, Jagiellonian University, Kraków, Poland.     

<Superscript>1</Superscript>H NMR spectra of water contained in solutions of poly(<Emphasis Type="Italic">N</Emphasis>-vinylpyrrolidone) and its modification products in CDCl<Subscript>3</Subscript>

¹H NMR spectra in CDCl₃ of poly(N-vinylpyrrolidone), epoxidized poly(N-vinyl-pyrrolidone), and products derived from the latter by modification with amino acids (glycine, β-alanine, γ-aminobutyric acid, and ε-aminocaproic acid) were examined. The ¹H NMR spectra of the modified polymers contain signals for water protons due to different centers of water sorption. These signals differ in chemical shift and integral intensity and indicate a changed spatial packing of the polymer as the result of its modification. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2377–2380, October, 2005.     

Natural monocrystalline chalcopyrite and galena as electrochemical sensors in non-aqueous solvents. Part II: potentiometric titrations of weak acids in N,N-dimethyformamide and N-methylpyrrolidone

Natural monocrystalline chalcopyrite and galena as new indicator electrodes for the potentiometric titration of weak acids in N,N-dimethylformamide and N-methylpyrrolidone were used. The investigated electrodes showed a linear dynamic response for p-toluenesulfonic acid concentrations in the range from 0.1 to 0.001 M, with a Nernstian slope of 59.0 mV for chalcopyrite and 33 mV per decade for galena in N,N-dimethylformamide, 56.1 mV for chalcopyrite, and 32.0 mV per decade for galena in N-methylpyrrolidone. The potential in the course of the titration and at the titration end point was rapidly established. Sodium methylate, potassium hydroxide, and tetrabutylammonium hydroxide proved to be very suitable titrating agents for these titrations. The response time was less than 10–11 s, and the lifetime of the electrodes is limitless. The advantages of the electrodes are log-term stability, fast response, reproducibility, easy preparation, and low cost. The results obtained in the determination of the investigated weak acids deviated on average by ±0.04–0.34% from those obtained with a glass electrode.     

N-(n-Alkyl)-N′-diphenylphosphorylureas as a new type of extractants for preconcentration of actinides and lanthanides

N-(n-Alkyl)-N′-diphenylphosphorylureas Ph₂P(O)NHC(O)NHC _n H_2n+1 (n = 6–10) were synthesized by the reaction of diphenylphosphoryl isocyanate with primary n-alkylamines C _n H_2n+1NH₂. The products (especially N-diphenylphosphoryl-N′-n-octylurea) are efficient extractants capable of extracting actinides and lanthanides from nitric acid solutions with high distribution coefficients. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 374–379, February, 2008.     

The reaction of salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides with dihalomethanes

Methylene-bis[N′-oxydiazene-N-(β-hydroxyalkyl)N-oxides] were synthesized by the reaction of salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides with diahalomethanes. The effect of the nature of the starting reagents and the reaction condtions on the yields of the target compounds was studied. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2266–2269, November, 1998.     

Intensification of Biocatalytical Processes by Synergistic Substrate Conversion. Fungal Peroxidase Catalyzed <Emphasis Type="Italic">N</Emphasis>-Hydroxy Derivative Oxidation in Presence of 10-Propyl Sulfonic Acid Phenoxazine

Many industrial pollutants, xenobiotics, and industry-important compounds are known to be oxidized by peroxidases. It has been shown that highly efficient peroxidase substrates are able to enhance the oxidation of low reactive substrate by acting as mediators. To explore this effect, the oxidation of two N-hydroxy derivatives, i.e., N-hydroxy-N-phenyl-acetamide (HPA) and N-hydroxy-N-phenyl-carbamic acid methyl ester (HPCM) catalyzed by recombinant Coprinus cinereus (rCiP) peroxidase has been studied in presence of efficient substrate 3-(4a,10a-dihydro- phenoxazin-10-yl)-propane-1-sulfonic acid (PPSA) at pH 8.5. The bimolecular constant of PPSA cation radical reaction with HPA was estimated to be (2.5 ± 0.2)·10⁷ M⁻¹ s⁻¹ and for HPCM was even higher. The kinetic measurements show that rCiP-catalyzed oxidation of HPA and HPCM can increase up to 33,000 times and 5,500 times in the presence of equivalent concentration of high reactive substrate PPSA. The mathematical model of synergistic rCiP-catalyzed HPA–PPSA and HPCM–PPSA oxidation was proposed. Experimentally obtained rate constants were in good agreement with those calculated from the model confirming the synergistic scheme of the substrate oxidation. In order to explain the different reactivity of substrates, the docking of substrates in the active site of the enzyme was calculated. Molecular dynamic calculations show that the enzyme–substrate complexes are structurally stable. The high reactive PPSA exhibited higher affinity to enzyme active site than HPA and HPCM. Furthermore, the orientation of HPA and HPCM was not favorable for proton transfer to the distal histidine, and different substrate reactivity was explained by these diversities.     

Automated Solid-Phase Extraction and Liquid Chromatography Tandem Mass Spectrometry Determination of N-methyl-2-pyrrolidone and its Metabolites in Urine and Plasma

A method for the simultaneous determination of N-methyl-2-pyrrolidone (NMP) and its metabolites 5-hydroxyl-N-pyrrolidone (5HNMP), N-methylsuccinimide (MSI) and 2-hydroxy-N-methylsuccinimide (2HMSI) in plasma and urine has been developed. Samples were purified by SPE using an ASPEC XL4. Analysis was performed using LC–MS equipped with an APCI interface. The analysis provided linear responses in the range of 0.125–12 μg mL⁻¹ for all of the analytes and up to 150 μg mL⁻¹ for 5HNMP and 2HMSI. The within day precision was in the range of 0.9–19.1% for plasma samples and 1.9–10.4% for urine samples whereas the between day precisions were 4.5–11.9% and 1.2–17.5%, respectively. The method was deemed to be suitable for monitoring the levels of NMP and its metabolites in the plasma and urine of occupationally exposed persons.     

Si-Containing Amides of Phosphoric Acid

Summary. The first representative of the N-silylmethylamides of phosphoric acid O=P[NMe(CH₂SiMe _n (OEt)_3-n ]₃ have been synthesized by interaction of MeNHCH₂SiMe _n (OEt)_3-n (n = 2, 3) with POCl₃. The interaction of the N,N′,N″-trimethyl-N,N′,N″-tris[(ethoxydimethyl- silyl)methyl]triamide phosphoric acid with BF₃·Et₂O or BCl₃ results in the formation of the N,N′,N″-trimethyl-N,N′,N″-tris[(fluorodimethyl-silyl)methyl]triamide phosphoric acid or N,N′,N″-trimethyl-N,N′,N″-tris[(chlorodimethylsilyl)methyl]triamide phosphoric acid. NMR data show on the tetracoordinate state of silicon in these products. Professor Vadim Aleksandrovich Pestunovich, our chief, teacher and friend died on July 4^th, 2004     

Gangliosides from the starfishEvasterias echinosoma: identification of a disialoganglioside containing 8-O-methyl-N-acetylneuraminic acid andN-formylgalactosamine

Gangliosides were isolated from the starfishEvasterias echinosoma and their structures were elucidated by chemical and physicochemical methods. Two major gangliosides were found to be disialogangliosides, whose carbohydrate chain is based on the trisaccharide β-N-acylgalactosaminyl-(l→3)-β-galactosyl-(l→4)-β-glucose (acyl is formyl or acetyl), both residue at of 8-O-methyl-N-acetylneuraminic acid being attached to theN-acylgalactosamine residue at positions 3 and 6. The minor components are disialogangliosides with linear carbohydrate chains in which the terminal sialic acid residue is attached to the penultimateN-acetylneuraminic acid residue at positions 4, 8, or 9. The lipid part of the gangliosides consists of sphingenine and unsubstituted fatty acids (mainly, palmitic and stearic acids). Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 156–161, January, 2000.     

S-ArylN,N-dialkylamidothiosulfates, a novel class of sulfenic acid derivatives

A method for the synthesis ofS-arylN,N-dialkylamidothiosulfates, a novel class of sulfenic acid derivatives, was proposed. The method is based on the reaction of arenesulfenyl chlorides withN,N-dialkylamidosulfinic acids or with secondary amines in liquid SO₂ in the presence of triethylamine. In the presence of halogen-containing Lewis acids,S-arylN,N-dialkyl-amidothiosulfates add to the C=C bonds to give aryl β-haloalkyl sulfides. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1484–1487, August, 2000.     

Effective synthesis of methyl 3β-amino-3-deoxybetulinate

A practical method for preparing methyl 3β-amino-3-dexoybetulinate that is based on column chromatographic separation of 3α- and 3β-t-butoxycarbonates and subsequent removal of the protecting group using formic acid is proposed. The structure of methyl 3β-N-(t-butoxycarbonyl)-3-deoxybetulinate was established by an x-ray structure analysis. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 488–490, September-October, 2008.     

Reactions of functionalized alkyl halides withN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxide salts

Some characteristic features of reactions ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxide salts with various α- and β-functionalized alkyl halides were established. Some α-and β-functionalizedN-(β-hydroxyalkyl)-N′-alkoxydiazeneN-oxides and e ethylenebis[N-(β-hydroxyalkyl)-N′-oxydiazeneN-oxides] were synthesized for the first time. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 123–129, January, 1999.     

Gangliosides from the starfishEvasterias echinosoma: identification of a disialoganglioside containing 8-O-methyl-N-acetylneuraminic acid andN-formylgalactosamine

Gangliosides were isolated from the starfishEvasterias echinosoma and their structures were elucidated by chemical and physicochemical methods. Two major gangliosides were found to be disialogangliosides, whose carbohydrate chain is based on the trisaccharide β-N-acylgalactosaminyl-(l→3)-β-galactosyl-(l→4)-β-glucose (acyl is formyl or acetyl), both residue at of 8-O-methyl-N-acetylneuraminic acid being attached to theN-acylgalactosamine residue at positions 3 and 6. The minor components are disialogangliosides with linear carbohydrate chains in which the terminal sialic acid residue is attached to the penultimateN-acetylneuraminic acid residue at positions 4, 8, or 9. The lipid part of the gangliosides consists of sphingenine and unsubstituted fatty acids (mainly, palmitic and stearic acids). Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 156–161, January, 2000.     

Effect of the amount and type of the crosslinker on the swelling behavior of temperature-sensitive poly(N-tert-butylacrylamide-co-acrylamide) hydrogels

Temperature-sensitive poly(N-tert-butylacrylamide-co-acrylamide) [P(NTBA-co-AAm)] hydrogels were synthesized by free-radical copolymerization in a water–methanol mixture using three types of crosslinkers: 1,2-ethyleneglycol dimethacrylate, N,N-methylenebisacrylamide, and 1,3-butandiol dimethacrylate. These thermosensitive hydrogels were swollen to equilibrium in water at 20°C and examined by gravimetric measurements. The influence of type and content of crosslinkers on the swelling ratio, the polymer–solvent interaction parameter (χ), the average molecular mass between crosslinks and the effective crosslinking density (ν _E) of the hydrogels were reported and discussed. The swelling process in water was found to be non-Fickian diffusion. The enthalpy (ΔH) and entropy (ΔS) changes appearing in the χ parameter for the hydrogels were determined by using the Flory–Rehner theory based on the phantom network model of swelling equilibrium. Negative values for ΔH and ΔS indicated that the hydrogels had a negative temperature-sensitive property in water; that is, swelling at a lower temperature and shrinking at a higher temperature. The temperature-reversibility and on–off switching properties of the P(NTBA-co-AAm) hydrogels may be considered as good candidates for designing novel drug-delivery systems.     

Interaction of Cucurbit[n = 6∼8]urils and Benzimidazole Derivatives

The structures and optical properties of host–guest complexes produced from cucurbit[n = 6–8]urils and some benzimidazole derivatives have been investigated by ¹H NMR spectroscopy, electronic absorption spectroscopy and fluorescence spectroscopy. The experimental results reveal that calculations of A∼N_Q[n]/N_guest and I_f∼N_Q[n]/N_guest for the same association complex both support a good fit to an identical binding model. In particular, the A∼N_Q[n]/N_guest, I_f∼N_Q[n]/N_guest calculations and the ¹H NMR determinations for three Q[6]–ge(1∼3) complexes and three Q[8]–ge(1∼3) complexes all support a binding model of 1:1 and 1:2 respectively.     

Determination of N-Acetylcysteine and Thioglycolic Acid in Human Urine

A method for the determination of total N-acetylcysteine and thioglycolic acid in human urine is described. Because these compounds are mainly excreted as disulfides, they are first reduced to the free thiols by treatment with tris(2-carboxyethyl)phosphine hydrochloride and then derivatized with 2-chloro-1-methylquinolinium tetrafluoroborate. Separation and quantitation of the 2-S-quinolinium derivatives of the thiols were achieved by reversed-phase ion-pair liquid chromatography with UV-detection at 355 nm. Because the method enables simultaneous determination of other endogenous urinary thiols, e.g. cysteine and cysteinylglycine, amounts of these compounds in urine were also studied. Detector responses were linear over the range covering most practical situations, with correlation coefficients for all four analytes better than 0.999. Recovery and imprecision (as RSD) were within 99.77–102.17 and 0.01–7.79%, respectively. The lower limit of detection was 0.25 μmol L⁻¹ urine for thioglycolic acid and N-acetylcysteine, and 0.12 μmol L⁻¹ urine for cysteine and cysteinylglycine. The method was used for analysis of urine samples from 29 healthy individuals to establish reference values for the thiols, normalized to creatinine. 3-Mercaptolactic acid, 2-mercaptopropionic acid, and mercaptoethanol were not present in the urine analyzed.     

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.     

Radiolysis of N,N-dimethylhydroxylamine and its radiolytic liquid organics

N,N-dimethylhydroxylamine (DMHA) is a novel salt-free reducing reagent used in the separation U from Pu and Np in the reprocessing of power spent fuel. This paper reports on the radiolysis of aqueous DMHA solution and its radiolytic liquid organics. Results show that the main organics in irradiated DMHA solution are N-methyl hydroxylamine, formaldehyde and formic acid. The analysis of DMHA and N-methyl hydroxylamine were performed by gas chromatography, and that of formaldehyde was performed by ultraviolet–visible spectrophotometry. The analysis of formic acid was performed by ion chromatography. For 0.1–0.5 mol L⁻¹ DMHA irradiated to 5–25 kGy, the residual DMHA concentration is (0.07–0.47) mol L⁻¹, the degradation rate of DMHA at 25 kGy is 10.1–30.1%. The concentrations of N-methylhydroxylamine, formaldehyde and formic acid are (8.25–19.36) × 10⁻³, (4.20–36.36) × 10⁻³ and (1.35–10.9) × 10⁻⁴ mol L⁻¹, respectively. The residual DMHA concentration decreases with the increasing dose. The concentrations of N-methylhydroxylamine and formaldehyde increase with the dose and initial DMHA concentration, and that of formic acid increases with the dose, but the relationship between the concentration of formic acid and initial DMHA concentration is not obvious.