Synthesis of novel amino squaric acids via addition of dianion enolates derived from N-Boc amino acid esters

Novel α-amino squaric acid analogs were synthesized by initial addition reaction of a dianion enolate generated from N-Boc amino acid tert-butyl ester to squaric acid diisopropyl ester, and subsequent decarboxylation of the resulting carboxylic acid moiety.     

Arylhydroxyacetic acids and amino acids derived from ethinylphenols

Conclusions A method of synthesis of arylhydroxyacetic acids and ammo acids derived from ethinylphenols has been developed in view of possible physiological activity of these compounds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1170–1172, May, 1970.     

Synthesis and characterization of supramolecular optically active bisamides derived from amino acids

The synthesis and phase transitional behaviour of three pairs of enantiomeric supramolecular hexacatenar liquid crystals (LCs) derived from natural α-amino acids such as l/d-alanine, l/d-leucine and l/d-valine are described. Their preparation with high enantiomeric purity was accomplished by condensing optically active (amino acid residue containing) trialkoxy amines with a 3,4,5-trialkoxy cinnamic acid core using a peptide coupling reagent namely, 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyl-uronium hexafluorophosphate (HBTU). The mesomorphic behaviour of these self-complementing mesogens was ascertained by polarising optical microscopy, differential scanning calorimetry and X-ray diffraction. The compounds exhibit columnar (Col) phase over a wide thermal range. Particularly, a pair of enantiomers derived from l/d-leucine residues notably stabilize hexagonal Col (Col_h) phase over a wide temperature range of ?5 °C to 180 °C. Circular dichroism (CD) and FTIR studies suggest the chiral (helical) organization of mesogens within the columns through intermolecular hydrogen bonding; thus, these enantiomers represent one of the rarely reported examples of LCs exhibiting supramolecular Col_h phase at room temperature. The gelation studies reveal the ability of these bisamides to form stable supramolecular gels in ethanol caused through H-bonding interactions.     

Parallel synthesis of novel heteroaromatic acromelic acid analogues from kainic acid

A range of new C-4 heteroaromatic acromelic acid analogues has been synthesized in a parallel fashion from (-)-alpha-kainic acid 1. Protection of the amine and carboxylate groups of 1 followed by ozonolysis gave methyl ketone 8. A silyl enol ether 9, generated regiospecifically from the methyl ketone 8 using "kinetic" conditions, was brominated in situ with phenyltrimethylammonium perbromide to give the key alpha-bromo ketone 10. Parallel cyclization reactions of bromo ketone 10 with thioamides and thioureas were then performed. The aromatic heterocyclic derivatives 11a-d and 19 produced were deprotected to give the new kainoid amino acids 6a-d and 25 in excellent yield. Compounds 6a and 6c show strong binding to the kainate receptor. Reaction of 10 with alternative condensing agents was also briefly investigated.     

Synthesis and characterization of novel water-soluble zinc(II) Schiff-base complexes derived from amino acids and salicylaldehyde-5-sulfonates

New water-soluble zinc(II) Schiff-base complexes derived from amino acids (glycine, L-phenylalanine, and L-valine) and salicylaldehyde-5-sulfonates (sodium salicylaldehyde-5-sulfonate and sodium 3-methoxy-salicylaldehyde-5-sulfonate) have been synthesized. The complexes were characterized by elemental analysis, IR, electronic, ¹H?NMR, and ¹³C?NMR spectra. In the IR spectra of the complexes, the large difference between the asymmetric ν_as(COO) and symmetric ν_s(COO) carboxylate stretch, Δν(ν_as(COO)–ν_s(COO)) of 199–247?cm^?1, indicates monodentate coordination of the carboxylate group. Spectral data showed that in these complexes the ligand is a tridentate ONO moiety, coordinating to the metal through its phenolic oxygen, imine nitrogen, and carboxyl oxygen.     

新型手性氨基酸烯砜的合成

以苯亚磺酸钠和3-氯-2-甲基-1丙烯为原料,经偶联、氯化、溴化,之后再与氨基酸胺化反应合成得到了两个新型手性氨基酸烯砜化合物。所获得化合物的结构经HR-MS,1H,13C和/或DEPT NMR验证。     

Synthesis of regioisomeric,stereoregular AABB-type polyamides from chiral diamines and diacids derived from natural amino acids

Two regioisomeric and stereoregular AABB-type polyamides have been synthesized using l-glutamic acid 1 and l-alaninol 4 as sources of chirality. From 4, two derivatives of chiral diamines were prepared and regioselectively condensed with pentachlorophenyl 5-oxo-(S)-2-tetrahydrofurancarboxylate 3, derived from 1. Manipulation of functional groups and convenient deprotections led to the ammonium salts of N-[1′-amino-(S)-2′-propyl]- and N-[(S)-2′-amino-1′-propyl]-5-oxo-(S)-2-tetrahydrofurancarboxyamide 11 and 15, respectively, in which the building blocks derived from 1 and 4 are linked through an amido group. Compounds 11 and 15 are, in fact, α,ω-amino acids having amino and lactone groups, and hence activated for polycondensation. Thus, polymerization of 11 took place under regio- and stereo-control to afford stereoregular poly[N-(1′-amino-(S)-2′-propyl)-carboxyamido-(S)-2-hydroxypentan-5-oic acid] (16). Similar polycondensation of 15, under the optimized conditions employed for the synthesis of 16, gave the regioisomeric polyamide 17, which exhibited a molecular weight lower than that of 16. The thermal and spectroscopic properties of optically active AABB-polyamides 16 and 17 are described.     

Synthesis of novel water-soluble linear and heterocyclic phosphino amino acids from 2-phosphinophenols or 2-phosphinophenolethers, formaldehyde and amino acids

Acyclic and cyclic amino acid derivatives of 2-phosphinophenols have been synthesised by reaction of primary phosphinophenols (4-R-2-H₂PC₆H₃OH; R=H, Me, OMe) 1a–c with formaldehyde and amino acids (o- and p-aminobenzoic acid, -lysine) via in situ formed hydroxymethyl species 2a–c. Condensation reactions with glycine did not afford defined products except when the methoxymethyl and tetrahydropyranyl ethers of 1d,e were used instead of the hydroxy compounds. o-Aminobenzoic acid gives rise to linear bis(o-carboxyphenylaminomethyl)phosphines 3a–e. p-Aminobenzoic acid, dependent on the molar ratio, affords bis(p-carboxyphenylaminomethyl)phosphines 4a,d as well as eight-membered heterocyclic 1,5,3,7-diazadiphosphacyclooctanes 5a–e. The aliphatic amino acids glycine and -lysine form six-membered heterocyclic 1,3,5-diazaphosphorinanes 6d and 7a–e, respectively, in presence of excess formaldehyde. -lysine differs from glycine by reaction at the terminal amino group. The structures of the compounds have been elucidated by multinuclear NMR spectroscopy. The salts of the phosphino amino acids are soluble in water. Water solubility increases with the number of hydrophilic groups, i.e. free phenols are more soluble than their ethers. Ligand concentrations in water from 0.1 to 1 M were observed.     

Synthesis of novel fullerene amino acids and their multifullerene peptides

[60]-Fullerene functionalized amino acids with 4-6 methylene spacers from α-carbon to the nitrogen atom of fulleropyrolidine and corresponding multifullerene peptides have been synthesized.     

Synthesis of modified amino acids containing nucleic acid purine bases

The reaction of hydrazides of adenylyl- or hypoxanthinyl-9-alkylcarboxylic acids with sodium nitrite in acid media gives reactive azides of purinyl-9-alkylcarboxylic acids which condense with ()-aminocarboxylic and ,-diaminocarboxylic acids to give N(N)-(adenylyl-9-alkanoyl) aminocarboxylic, N-(adenylyl-9-)- and N-(hypoxanthinyl-9-alkanoyl)-,-diaminocarboxylic acids. The deamination of N-(adenyl-yl-9-alkanoyl)aminocarboxylic acids gives N-(hypoxanthinyl-9-alkanoyl)aminocarboxylic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 126–130, January, 1985.     

New generation ionic liquids: cations derived from amino acids

Two families of a new generation of ionic liquids, in which the chiral cations are directly derived from naturally occurring alpha-amino acids and alpha-amino acid ester salts, have been obtained via very simple preparations.     

Synthesis of novel quaternary amino acids using molybdenum-catalyzed asymmetric allylic alkylation

The Mo-catalyzed asymmetric allylic alkylation using azlactones provides extraordinary levels of selectivity. Thus, a wide range of cinnamyl-type substrates react with 2-methyl and 2-benzyl azlactones to give only the product resulting from attack at the more substituted carbon. Using other alkyl substituents such as 2-methylthioethyl, isobutyl, allyl, and isopropyl provides products that still retain excellent regioselectivity but small quantities of the linear product are also observed. In all cases, excellent diastereo- and enantioselectivity of the branched alkylated product are observed. This new asymmetric reaction provides ready access to unusual quarternary amino acids, important building blocks for biological applications. The reactions complements the Pd AAA wherein the cinnamyl substrate leads to only the product of attack at the primary terminus of the allyl moiety.     

Synthesis and polymerisation of lipophilic peptide nucleic acids derived from stearic acid and pentacosa-10,12-diynoic acid

The adenine, cytosine and thymine peptide nucleic acid (PNA) monomers and PNA T₁₀ oligomers bearing either a diacetylenic or stearoyl moiety at the N- or C-terminus have been successfully prepared. The resulting thymine monomeric and T₁₀-mer derivatives have been subsequently incorporated into polydiacetylene-containing liposomes.     

Aziridines derived from amino acids as synthons in pseudopeptide synthesis

The reactivity of the Z-protected aziridine derived from aspartic acid has been studied with various N- and O-nucleophiles. The optimized reaction conditions allow quick and easy access to 1, 2-diamines or amino alcohols. In the case of opening with N-nucleophiles, very good regioselectivity was observed. Use of an α-amino ester as the nucleophile yielded a methyleneamino pseudodipeptide.     

Synthesis and characterization of new lead(II) complexes of Schiff bases derived from amino acids

Some new lead(II) complexes of the general formula Pb(L)₂, where HL = Schiff bases derived from the condensation of isatin and chloroisatin with phenylalanine (HL¹/HL⁴), isoleucine (HL²/HL⁵), and glycine (HL³/HL⁶), have been synthesized and characterized by elemental analysis, molar conductance, electronic, infrared, and multinuclear magnetic resonance (¹H and ¹³C) studies. In all cases, the Pb atom is in a four-coordinated environment with two bidentate deprotonated Schiff bases binding as monoanionic ligands through the oxygen and azomethine nitrogen. The 3D molecular modeling and analysis for bond lengths and bond angles have also been carried out for one of the representative compounds, [Pb(L³)₂] to substantiate the proposed structures.     

Products from dehydration of dicarboxylic acids derived from anthranilic acid

Treatment of N-(carboxymethyl)-anthranilic acids 1 with several dehydrating agents, gave the cyclic ortho amides 6, or the 7-membered anhydrides 7. After reaction of N-(carboxymethyl)-anthranilic acid (1a) with acetic anhydride, a diacetylated fused diketopiperazine indole dimer (18) could be isolated. Dehydrations of 2,2'-iminobis-benzoic acid led to the corresponding cyclic ortho amides 23. The dynamic behaviour of some of these compounds, and their precursors, was studied.     

Synthesis of new chiral imidazolium salts derived from amino acids: their evaluation in chiral molecular recognition

A family of new imidazolium salts derived from natural amino acids has been synthesized and tested for NMR enantiodiscrimination, as chiral shift reagents, of carboxylic acids. These imidazolium receptors contain different structural modifications and the splitting of the signals of the acids, after addition of the corresponding CSRs, depends on these structural variables. Compound 8b exhibited the strongest chiral solvating properties for racemic Mosher acid and was recognized as a suitable CSR for the determination of its enantiomeric composition.     

Synthesis and immunomodulatory activity of some novel amino acid germinates

Amino acid germanate compounds are synthesized by the chemical reaction of germanium dioxide with a selected amino acid in the presence of an alkali medium at a suitable elevated temperature. Amino acids included in the novel synthesis include histidine, methionine and glutathione. The study evaluated their effects on induction of interleukin-12 and interferon-γl in Swiss albino Webster rats. The new germanium compounds, especially bis-methionino germanate, are considered as good interferon inducer that significantly enhance the immunologic function.