Synthesis of novel O,O"-dialkyl α-aminoalkylphosphonothioates

O,O"-Dialkyl -amino(cyclohexyl)phosphonothioates were synthesized by the reactions of O,O"-dialkyl phosphonothioites with [2-(N-cyclohexylideneamino)ethyl] vinyl ether.     

Synthesis of esters of α-vinyloxyethylcarbamodithioic acid

Mono and diesters of 2-vinyloxyethylcarbamodithioic acid were synthesized by the reaction of (1-p-nitrophenyl)-2-vinyloxyethylaminoethanol with carbon disulfide. 3-[2-(Vinyloxyethyl)]-5-(4-nitrophenyl)-1,3-thiazolidine-2-thione was prepared and its structure was proved by X-ray diffraction analysis.     

Adducts of mononuclear oxomolybdenum(IV)O,O′-dialkyl(alkylene) dithiophosphate complexes with pyridine, 2,2′-bipyridyl and 1, 10-phenanthroline

Summary Equimolar adducts of mononuclear oxomolybdenum(IV)O,O-dialkyl and alkylene dithiophosphates with heterocyclic amines, MoO[S₂P(OR)₂]₂·L (where when R=Et,i-Bu; L=pyridine and when R=Et,n-Pr,i-Bu; L=2,2-bipyridyl, 1,10-phenanthroline) and (where G=CH₂CMe₂CH₂, L=2,2-bipyridyl and when G=CMe₂CMe₂; L=pyridine) have been prepared by reacting the corresponding oxomolybdenum(IV) complexes with an excess of pyridine or with bipyridyl or phenanthroline in a 11 molar ratio.The complexes have been characterized by elemental analyses and molecular weight determinations. Their probable structures are proposed on the basis of i.r. and n.m.r. (¹H,¹³C and³¹P) spectral data, which are consistent with a 6-coordinated octahedral structure for all the base adduct complexes.     

Addition of esters of nitroacetic acid to α,β-unsaturated ketones

Summary The addition reaction of esters of nitroacetic acid to, -unsaturated ketones was studied, and new esters of ketonitroacids were prepared.     

Synthesis of some esters of α-acetoxy-Β,Β,Β-trichloroethylphosphonic acid

Summary By the reaction of dialkyl esters of -hydroxy, ,-trichloroethylphosphonic acid and acetic anhydride in the presence of a few drops of sulfuric acid, the dialkyl esters of -acetoxy-,,-trichloroethylphosphonic acid were obtained in high yields.     

Triisopropoxyniobium(V) and tantalum(V)bis-O,O′-dialkyl dithiophosphates

Summary Triisopropoxy bis(O,O-dialkyl dithiophosphates), (i-PrO)₃M[S₂P(OR)₂]₂ (M = Nb^v, Ta^v; R = n-Pr, i-Pr, i-Bu and Ph) have been prepared by reacting the appropriate triisopropoxymetal(V)dichloride, (i-PrO)₃MCl₂ (1 mol) with sodium/ammonium dialkyl dithiophosphates (2 mols)in THF. The monomeric products which are viscous liquids, soluble in common organic solvents and highly susceptible to hydrolysis, were characterized by i.r. and n.m.r. spectra which indicate a bidentate mode of attachment of dithiophosphato groups to the metal.     

Catalytic α-allylation of unprotected amino acid esters

Catalytic α-allylation of unprotected amino acid esters to produce α-quaternary α-allyl amino acid esters is reported. Catalytic loadings of picolinaldehyde and Ni(II) salts induce preferential reactivity at the enolizable α-carbon of amino acid esters over the free nitrogen with electrophilic palladium π-allyl complexes. Fourteen examples are given. Additionally, the use of chiral ligands to access enantioenriched α-quaternary amino acid esters from racemic precursors is demonstrated by the enantioselective synthesis of α-allyl phenylalanine methyl ester from racemic phenylalanine methyl ester.     

Polarity and structure of α-nitrocinnamic acid esters

Polarity and structure of ethyl α-nitrocinnamates have been studied by means of dipole moments method and quantum-chemical calculations. These compounds exist in the form of Z-isomers in solution, that is, nitro group and benzene ring are cis-positioned.     

Rotational isomerism and solvent effect on infrared intensities of ν(CO) stretching band in methyl alkyl ketones

A solvent-sensitive rotational equilibrium has been observed in several methyl alkyl keyones. This equilibrium arises from the rotational of the R group around thr R-(CO) bond. The variation in relative intensity of the two bands observed in methyl isobutyl ketone has been measured. Frequency and intensity of each band and the total intensity have been ralated to the solvent properties using the G parameter as a measure solvent polarity. From these relationships the stable conformer in gas phase has been determined.     

A simple method for the oxidation of α-amino acid esters to α-oximino esters

Magnesium bis(monoperoxyphthalate) hexahydrate (MMPP) was found to be an effective reagent for the oxidation of various α-amino acid esters to the corresponding α-oximino acid esters. This transformation could be completed under mild conditions within 2.5 h using 1.1 equiv of MMPP in THF. Clean oximino esters were obtained after quenching and extracting the reaction from sodium thiosulfate solution. The O-phosphorylated derivative of 2-oximinoglutarate exhibited slow binding inhibitory potency for the metallopeptidase prostate-specific membrane antigen (PSMA) with an IC₅₀ value of 58 nM.     

Silicon-containing esters of α-cyanoacrylic acid: synthesis and properties

A number of cyanoacetates have been synthesized: cyanoacetoxymethyitrimethylsilane (1), cyanoacetoxymethylpentamethyldisiloxane (2), cyanoacetoxyetoxymethylpentamethyldisiloxane (3). They were converted by the Knoevenagel reaction to novel esters of a-cyanoacrylic acid (4–13) containing silicon atoms in the ester groups and having the general formula RCH=C(CN)COOCH₂X (where R=H, 4-MeOC₆H₄, MeCH=CH, 2-furyl; X=SiMe₃, SiMe₂OSiMe₃, CH₂OCH₂SiMe₂OSiMe₃). These compounds are capable of copolymerization with esters of cyanoacrylic acid which are the precursors to adhesives for cold curing.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 949–952, May, 1993.     

Hydrogenation of α-cyanoacrylic acid and its esters by organohydridesilanes

The C=C bond in -cyanoacrylic acid is readily hydrogenated by organohydridesilanes in the absence of catalyst. The hydrogenation of -cyanoacrylate esters requires the presence of acid.A. N. Nesmeyanov Institute of Organometallic Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1655–1657, July, 1992.     

Preparation and characterization of organogermanium O,O′-dimethyl and diethyl-dithiophosphates

Organogermanium derivatives of dithiophosphoric acid of general formula R₄−_nGe[SP(S)(OR′)₂]_n, where n = 1–3, R, = Me, Ph and R′ = Me, Et, have been prepared and characterized by means of ¹H, ¹³C NMR and vibrational spectroscopy and mass spectrometry. The spectroscopic results indicate that the dithiophosphate groups are monodenate and that an approximate tetrahedral geometry about the germanium atom is maintained. This is in part confirmed by a preliminary X-ray crystallographic determination of PhGe[SP(S)(OMe)₂]₃, whose crystals are orthorhombic, space group Pn2₂₁a, a 13.674(4), b 14.566(3), c 13.154(3) Å, V 26201(1) ų and Z = 4 from 1225 observed reflections [1 > 2σI].     

Role of tautomerism and rotational isomerism in the interaction of α-hydroxyanthraquinones with boric acid

The products of reaction of α-hydroxyanthraquinones with boric acid are mixtures of 9,10-, 1,10 -, 1,4- and 1,5-quinoid tautomeric complexes of boric acid and borate esters differing by the coordination bonds with carbonyl groups existing in the dynamic equilibrium. The deepening of the reagents color in the presence of boron does not a result only of the complexation, but in the accompanying shift of the tautomeric equilibria.     

Synthesis,spectral characterization,and evaluation of antimicrobial activity of O,O′-alkanediyl S-(N-phthalimidomethyl) dithiophosphates and zinc bis(O,O′-alkanediyl) dithiophosphates

The synthesis of novel dithiophosphate derivatives has been achieved. Two O,O′-alkanediyl S-(N-phthalimidomethyl) dithiophosphates and two Zinc bis(O,O′-alkanediyl) dithiophosphates are synthesized by an easy and facile chemical synthetic route. Zinc bis[O,O′-(2-methylpentane-2,4-diyl) dithiophosphate] L¹, Zinc bis[O,O′-(2-ethylhexane-1,3-diyl) dithiophosphate] L², O,O′-(2-methylpentane-2,4-diyl) S-(N-phthalimidomethyl) dithiophosphate L³ and O,O′-(2-ethylhexane-1,3-diyl) S-(N-phthalimidomethyl) dithiophosphate L⁴ are synthesized from the respective ammonium salts. Compounds L¹, L², L³, and L⁴ are characterized by (CHN) elemental analysis, ESI mass, FT-IR, ¹H, ¹³C, and ³¹P NMR techniques. The crystal structure of ammonium O,O′-(2-methylpentane-2,4-diyl) dithiophosphate is discussed. L¹, L², L³, and L⁴ were evaluated for antimicrobial activity. It was found that the phthalimide derivatives L³ and L⁴ showed much better antifungal potential against some species of fungus. The Zinc dithiophosphates L¹ and L² showed good antibacterial activity against Bacillus cereus and Escherichia coli.     

Facile syntheses of fluorine-containing α,β-unsaturated acids and esters from 2-trifluoromethylacrylic acid

Various types of fluorine-containing α,β-unsaturated acids and their esters were synthesized from 2-trilfuoromethylacrylic acid as a sole starting material.     

Asymmetric transfer hydrogenation of beta,gamma-alkynyl alpha-imino esters by a Brønsted acid

Asymmetric synthesis of trans-alkenyl alpha-amino esters was realized by chiral phosphoric acid catalyzed transfer hydrogenation of beta,gamma-alkynyl alpha-imino esters. Utilizing Hantzsch esters as the hydrogen donor, both the alkyne and imine moieties of beta,gamma-alkynyl alpha-imino esters were reduced to afford trans-alkenyl alpha-amino esters with up to 96% ee.