Synthesis of Derivatives of ω-Isocyanato-α-methylamino, ω-Ureido-α-methylamino,and N<Superscript>α</Superscript>-Methyl-α, ω-diamino Acids

Summary.  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. Received November 17, 1999. Accepted November 26, 1999     

Stereoselective,nonracemic synthesis of ω-borono-α-amino acids

ω-Unsaturated α-amino acids are synthesized through condensation of allyl and propargyl bromides or of 9-bromoundecene with a Ni(II) complex of the Schiff base derived from glycine and BPB. Hydroboration with Ipc₂BH followed by oxidation with acetaldehyde affords enantiomerically pure ω-borono-α-aminocarboxylic acids.     

Physical properties of four α, ω-dimethoxyfluoropolyethers

Several physical properties of four samples of linear α, ω-dimethoxyfluoropolyethers, varying in length from 6 to 14 chain atoms, i.e. carbon plus oxygen atoms, are reported and discussed. Among them are boiling points, glass and melting transition temperatures, specific volumes and their temperature coefficients, refractive indices and thermodynamic data such as cohesive energy density and melting enthalpies. The experimental data have been analysed, when possible, on the basis of the group contribution method, the results of which are in agreement with literature data. The above results are compared with those of two analogous series of fluoropolyethers whose chain ends are, respectively, OCF₂H and OCF₃. As expected, with increasing chain length, the effect of the OCF₂H and OCH₃ ends decreases progressively so that for chains longer than approximately 15-20 atoms, the differences among the three series should disappear.     

Fluorescence quantum yields of α, ω-diphenylpolyenes

Absolute fluorescence quantum yields of trans-stilbene and all-trans α, ω-diphenylpolyenes with the polyene double-bond number (n) from two to six have been determined in a room-temperature solvent. The 1¹Bu-fluorescence yield measured as a function of the polyene chain length shows a maximum for n = 2, while the 2¹Ag-fluorescence yield shows a maximum for n = 3, and both yields decrease with further increase of n. The observed quantum yield behavior is discussed briefly.     

N α,N ω-DIPHOSPHONO-, DIPHOSPHINO-METHYL-L-α,ω-DIAMINOCARBOXYLIC ACIDS

Abstract

Treatment of N-hydroxymethylated lactames 1,4-diamino-L-butanoic acid–1, L-ornithine–2, and L-lysine–3 is carried out with phosphorus trichloride to give the phosphonic acids 4, 5 and 6, and with methyldichlorophosphine to give the methylphosphinic acids 7, 8 and 9, which after alkaline hydrolysis liberate the carboxylic acids 10–15. Analogously, from the L-lysine derivative–16 and the aminomethylphosphonic acid derivative 18, the acids 15 and 19 are obtained after hydrolysis. The herbicidal activity of the lysine derivative 15 is established.     

The synthesis of ω-thienylalkane acids from ω-chloroalkane acids

Summary We have worked out a preparative method for the synthesis of -thienylalkane acids by acylation of thiophene with -chloroalkane acid chlorides followed by conversion of the resulting -chloroalkyl(2-thienyl)ketones into the corresponding acids by reaction with sodium malonic ester or potassium cyanide, and reduction of the resulting products with their simultaneous hydrolysis.Here and later we mean -(2-thienyl)alkne acids.We take this opportunity to thank R. Kh. Freidlina, A. A. Beér, and M. A. Besprozvannii for giving us enough -chloroalkane acids.     

Chemiluminescence determination of ω-chloroacetophenone

A chemiluminescence method for the determination of ω-chloroacetophenone in ethanolic extracts is elaborated. The method is based on the linearity of the concentration dependence of the intensity of luminol chemiluminescence upon the action of peroxide species forming in the reaction of ω-chloroacetophenone with air oxygen activated by hemin in alkaline solutions. The detection limit makes (1.0 ± 0.3) × 10⁻⁵ mg/mL (P = 0.95, n = 5, RSD = 32 %) at 293 K.     

Synthesis, characterization, and antifungal studies of transition metal complexes of ω-bromoacetoacetanilide isonicotinylhydrazone

Isonicotinic acid hydrazide or isonicotinylhydrazide, commonly known as isoniazid, is an antibacterial agent that has been used to treat tuberculosis. It interacts with microbial cell walls. Schiff’s bases or anils are the compounds having >C=N−N< linkages, which have immense applications as catalysts, stabilizers, pigments, dyes, and drugs. They have good ability to form chelates with many metal ions. Isoniazid can form Schiff’s bases with diketones such as acetoacetanilide. Acetoacetanilide isonicotinylhydrazone and its metal chelates exhibit anticancer activity. Our studies on N-methyl-acetoacetanilide isonicotinylhydrazone and its metal chelates revealed that they are active against pathogenic fungal strains. Hence, it is worthwhile to synthesize new complexes of ligands having different substituents on the acetoacetanilide moiety. We synthesized five new metal chelates of ω-bromoacetoacetanilide isonicotinylhydrazone. The ligand behaved as a tridentate monoanion or as a tridentate dianion in the complexes. These compounds were characterized mainly by elemental analysis; conductivity measurements; and electronic, infrared, and nuclear magnetic resonance spectral studies. We also carried out antifungal studies of these compounds against four selected pathogenic fungal strains using a cup-plate technique. Both the ligand and its metal chelates were active against all fungal strains investigated. However, the chelates were found to be more active than the ligand.     

Synthesis of phthalonitriles containing ω-alkenyl, ω-(alkylsulfanyl)alkyl, and ω-(alkylsulfonyl)alkyl substituents and phthalocyanine derivatives based thereon

Alkylation of phthalonitrile radical anion sodium salt with terminal alkenyl bromides (4-bromobut-1-ene, 5-bromopent-1-ene, and 6-bromohex-1-ene) gave the corresponding 4-alkenylphthalonitriles which reacted with alkanethiols (BuSH and n-C₁₀H₂₁SH) to produce 4-(ω-alkylsulfanylalkyl)phthalonitriles. Oxidation of the latter with hydrogen peroxide afforded 4-(ω-alkylsulfonylalkyl)phthtalonitriles. 4-Alkenyl- and 4-(ω-alkylsulfonylalkyl)phthalonitriles were brought into condensation with zinc(II) acetate to obtain the corresponding zinc phthalocyanines.     

Microwave-assisted synthesis of dialkyl ω-azidoalkylphosphonates

An efficient and reproducible microwave-assisted synthesis of dialkyl ω-azidoalkylphosphonates via nucleophilic substitution of the appropriate dialkyl ω-bromoalkylphosphonates by sodium azide in water or dimethylformamide (DMF) as solvent has been developed. This process has been optimized for batch reactors. The target, structurally diverse dialkyl ω-azidoalkylphosphonates with different steric hindrance around the phosphonato groups and containing unbranched side carbon chains of different lengths (n?=?2–6), has been obtained in moderate to high yields (39–87%).     

Reaction of ω-Vinyloxyalkylamines with Isatin

3-(-Vinyloxyalkylimino)-2,3-dihydroindol-2-ones and 3-(vinyloxyphenylimino)-2,3-dihydroindol-2-ones were synthesized in 34-93% yield by reactions of -aminoalkyl and aminophenyl vinyl ethers with isatin.     

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.     

Superacidic cyclization of ω-hydroxygeraniol diacetate and ω-hydroxygeraniol benzyl ether acetate

Low-temperature superacidic cyclization of (E,E)-3,7-dimethylocta-2,6-diene-1,8-diol (ω-hydroxygeraniol) diacetate and (E,E)-8-acetoxy-1-benzyloxy-3,7-dimethylocta-2,6-diene leads to the same mixtures of two diastereomeric 9-acetoxy-8-hydroxy-p-menth-1-enes epimeric at the C(8) atom. Translated fromIzvestiya Akademii Nauk Seriya Khimicheskaya, No. 1, pp. 135–138, January, 1999.     

Photocrosslinking of Silicones. Part XV. Cationic Photocrosslinking of α, ω, 4-Terminated Disiloxanes

Abstract

The photoinduced cationic crosslinking of α, ω-terminated disiloxanes (epoxy, vinyl ether, propenyl ether) has been investigated by means of Real-Time IR spectroscopy. A lipophilic iodonium salt and three lipophilic sulfonium salts were used as photoinitiator. The crosslinking rate is influenced by the type of α, ω-terminated disiloxane used and differed by a factor of more than 100 from the aliphatic epoxy to the vinyl ether derivatives. Moreover, the sulfonium salts were found to have a lower initiation efficiency than the lipophilic iodonium salt in the various systems studied. These results are in good agreement with the quantum yield of proton formation in a hexamethyldisiloxane/dimethoxyethane mixture. The final degree of conversion is larger with the ene derivatives than with the epoxy derivatives. The application of a kinetic method allows us to estimate the rate constant of the termination step (k_t and for the propenyl derivative the rate constant of the propagation step kp. The termination step can be described by means of a first order reaction. k_t was found to depend on the light intensity and the type of initiators used, whereas k_p is independent of the initiator used.     

Energetics of intramolecular hydrogen bonds and conformations of ω-diphenylphosphoryl- and ω-diphenylthiophosphoryl-substituted aliphatic alcohol molecules

A series of conformationally heterogeneous and energetically multilevel -diphenylphosphoryl- and -diphenylthiophosphoryl-substituted aliphatic alcohols, whose molecules are capable of five-, six-, and seven-membered ring closure due to the OH...O=P or OH...S=P intramolecular hydrogen bond (IHB), was studied by IR spectroscopy and molecular mechanics. The data obtained confirm the previous assumption that the energy of IHB (E _IHB) differs substantially from the difference of enthalpies of conformers with and without IHB (–H ), which is experimentally determined by the temperature dependence of the intensity of IR (OH) absorption bands. The measured –H values can be positive, zero, or negative at significant IHB effects, i.e., at high (OH) and E _IHB values.