- Organocatalytic Decarboxylation of Amino Acids as a Route to Bio-based Amines and Amides
-
Amino acids obtained by fermentation or recovered from protein waste hydrolysates represent an excellent renewable resource for the production of bio-based chemicals. In an attempt to recycle both carbon and nitrogen, we report here on a chemocatalytic, metal-free approach for decarboxylation of amino acids, thereby providing a direct access to primary amines. In the presence of a carbonyl compound the amino acid is temporarily trapped into a Schiff base, from which the elimination of CO2 may proceed more easily. After evaluating different types of aldehydes and ketones on their activity at low catalyst loadings (≤5 mol%), isophorone was identified as powerful organocatalyst under mild conditions. After optimisation many amino acids with a neutral side chain were converted in 28–99 % yield in 2-propanol at 150 °C. When the reaction is performed in DMF, the amine is susceptible to N-formylation. This consecutive reaction is catalysed by the acidity of the amino acid reactant itself. In this way, many amino acids were efficiently transformed to the corresponding formamides in a one-pot catalytic system.
- Claes, Laurens,Janssen, Michiel,De Vos, Dirk E.
-
p. 4297 - 4306
(2019/08/26)
-
- Method for preparing 3-methylthio propylamine
-
The invention provides a preparation method of 3-methylthio propylamine. The method is characterized in that under the effects of microwaves and ultrasonic waves, flavoring essence of 3-methylthio propyl alcohol capable of being easily obtained in China is used as a starting raw material; the reaction time is short; the total yield is relatively high. Under the effects of microwaves and ultrasonicwaves, firstly, 3-methylthio propyl alcohol and thionyl chloride react for 20 to 60 min under the back flow condition to prepare 3-methylthio-1-chloropropane, and the yield is greater than 95 percent; then, at 80 to 90 DEG C, the 3-methylthio-1-chloropropane and phthalimide potassium react for 0.5 to 2.5h to prepare N-3-methylthio propyl phthalimide, and the yield is greater than 94 percent; finally, the N-3-methylthio propyl phthalimide and hydrazine hydrate perform backflow reaction in absolute ethyl alcohol for 20 to 60min to prepare the 3-methylthio propylamine, and the yield is greater than 85 percent.
- -
-
Paragraph 0007; 0023; 0027; 0031; 0035
(2018/03/24)
-
- Preparation of functional styrenes from biosourced carboxylic acids by copper catalyzed decarboxylation in PEG
-
A general protocol for the copper-catalyzed decarboxylation of α,β-unsaturated carboxylic acids in PEG, particularly of biosourced cinnamic acid analogues, is reported. Moderate to high isolated yields (31-96%) towards the styrene derivatives were obtained. For the first time, decarboxylation of α-amino acids to the corresponding amines was successfully performed with good to high yields and extended to the decarboxylation of a few condensed heterocyclic compounds. Both the use of PEG as a green solvent and direct separation of the pure product of the reaction by distillation permitted the reuse of the solvent and the Cu-based catalytic system over several cycles without deactivation. This was extended to the synthesis of 4-vinylguaiacol on the laboratory scale in an average 92% yield. This journal is the Partner Organisations 2014.
- Cadot, Stephane,Rameau, Nelly,Mangematin, Stephane,Pinel, Catherine,Djakovitch, Laurent
-
supporting information
p. 3089 - 3097
(2014/06/10)
-
- Radiation chemical studies of methionine in aqueous solution: Understanding the role of molecular oxygen
-
The oxidation of methionine is an important reaction in the biological milieu. Despite a few decades of intense studies, several fundamental aspects remain to be defined. We have investigated in detail the γ-radiolysis of free methionine in the absence and presence of molecular oxygen followed by product characterization and quantification. The primary site of attack by HO? radicals and H? atoms is the sulfur atom of methionine. We have disclosed that HO? radicals do not oxidize methionine to the corresponding sulfoxide in either the presence or the absence of oxygen; the oxidizing species is H2O2 derived either from the radiolysis of water or from the disproportionation of the byproduct O2?-. 3-Methylthiopropionaldehyde is the major product of HO? radical attack in the presence of molecular oxygen. Together with the direct oxidation at sulfur as the major product, the potential of H? atoms is also proven to be highly specific for sulfur atom attack under anoxic and aerobic conditions. The major products derived from the H? atoms attack are found to be α-aminobutyric acid or homoserine, in the absence or presence of oxygen, respectively. All together, these results help clarify the fate of methionine related to a biological environment and offer a molecular basis for envisaging other possible pathways of in vivo degradation as well as other markers.
- Barata-Vallejo, Sebastian,Ferreri, Carla,Postigo, Al,Chatgilialoglu, Chryssostomos
-
scheme or table
p. 258 - 263
(2011/02/26)
-
- Tetracyclic benzimidazole derivatives and combinatorial libraries thereof
-
The present invention relates to novel tetracyclic benzimidazole derivative compounds of the following formula: wherein R1to R10have the meanings described in here. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing tetracyclic benzimidazole derivative compounds.
- -
-
-
- High-Precision Position-Specific Isotope Analysis of 13C/ 12C in Leucine and Methionine Analogues
-
We report an automated method for high-precision position-specific isotope analysis (PSIA) of carbon in amino acid analogues. Carbon isotope ratios are measured for gas-phase pyrolysis fragments from multiple sources of 3-methylthiopropylamine (3MTP) and isoamylamine (IAA), the decarboxylated analogues of methionine and leucine, using a home-built gas chromatography (GC)-pyrolysis-GC preparation system coupled to a combustion-isotope ratio mass spectrometry system. Over a temperature range of 620-900 °C, the characteristic pyrolysis products for 3MTP were CH4, C 2H6, HCN, and CH3CN and for IAA products were propylene, isobutylene, HCN, and CH3CN. Fragment origin was confirmed by 13C-labeling, and fragments used for isotope analysis were generated from unique moieties with >95% structural fidelity. Isotope ratios for the fragments were determined with an average precision of SD(δ13C) 13C) 13C values of fragments were invariant over a range of pyrolysis temperatures. The Δδ13C of complementary fragments in IAA was within 0.8‰ of the Δδ13C of the parent compounds, indicating that pyrolysis-induced isotopic fractionation is effectively taken into account with this calibration procedure. Using Δδ 13C values of fragments, Δδ13C values were determined for all four carbon positions of 3MTP and for C1, C2, and the propyl moiety of IAA, either directly or indirectly by mass balance. Large variations in position-specific isotope ratios were observed in samples from different commercial sources. Most dramatically, two 3MTP sources differed by 16.30‰ at C1, 48.33‰ at C2, 0.37‰ at C3, and 5.36‰ at C(methyl). These PSIA techniques are suitable for studying subtle changes in intramolecular isotope ratios due to natural processes.
- Sacks, Gavin L.,Brenna, J. Thomas
-
p. 5495 - 5503
(2007/10/03)
-
- One-pot sequence for the decarboxylation of α-amino acids
-
Treatment of an α-amino acid with N-bromosuccinimide in water at pH 5 or in an alcoholic-aqueous ammonium chloride mixture, followed by addition of nickel(II) chloride and sodium borohydride, effected an overall decarboxylation via an intermediate nitrile to afford the corresponding amine in good yield.
- Laval, Gilles,Golding, Bernard T.
-
p. 542 - 546
(2007/10/03)
-
- 2-aminobenzoxazole derivatives and combinatorial libraries thereof
-
The present invention relates to novel 2-aminobenzoxazole derivative compounds of the following formula: wherein R1 to R4 and Z have the meanings provided herein. The invention further relates to combinatorial libraries containing two or more such compounds, as well as methods of preparing 2-aminobenzoxazole derivative compounds.
- -
-
-
- 5-amino-6-cyclohexyl-4-hydroxy-hexanamide derivatives as inhibitors of β-amyloid protein production
-
A series of 5-amino-6-cyclohexyl-4-hydroxy-hexanamide derivatives of Formula I have been synthesized. STR1 As inhibitors of the production of β-amyloid protein from β-amyloid precursor protein, these compounds are expected to be effective in treating patients suffering from or susceptible to conditions or disorders linked to brain accumulation of β-amyloid protein; e.g., Alzheimer's Disease and Down's Syndrome.
- -
-
-
- 5-Amino-6-cyclohexyl-4-hydroxy-hexanamide derivatives as inhibitors of beta-amyloid protein production
-
A series of 5-amino-6-cyclohexyl-4-hydroxy-hexanamide derivatives of Formula I have been synthesized. As inhibitors of the production of β-amyloid protein from β-amyloid precursor protein, these compounds are expected to be effective in treating patients suffering from or susceptible to conditions or disorders linked to brain accumulation of β-amyloid protein; e.g., Alzheimer's Disease and Down's Syndrome.
- -
-
-
- An efficient synthesis of 2,8-diazabicyclo[4.3.0]-nonane derivatives via intramolecular cyclization reaction
-
Novel 5-functionalized-2,8-diazabicyclo[4.3.0]nonane derivatives 5 were synthesized from epoxide 1 through 4 steps in 46.7 ~ 52.6% yield.
- Lee,Son,Lee,Jung,Yoon,Park
-
p. 3741 - 3746
(2007/10/03)
-
- BIOTRANSFORMATION OF ORGANIC SULFIDES. PART 7. FORMATION OF CHIRAL ISOTHIOCYANATO SULFOXIDES AND RELATED COMPOUNDS BY MICROBIAL BIOTRANSFORMATION
-
The fungi Helminthosporium species NRRL 4671 and Mortierella isabellina ATCC 42613 have been used for the biotransformation of a series of isothiocyanatoalkyl methyl sulfides and their synthetic precursors, ω-(methylthio)alkylphthalimides.H. species gave predominantly (S) sulfoxides in all cases; M. isabellina gave (R) isothiocyanatoalkyl methyl sulfoxides, but in the case of two ω-(methylthio)alkylphthalimides substantial conversion of sulfoxide to sulfone resulted in the isolation of the former with predominant (S) configuration.A correction is made of the previously reported configurations of two biotransformation products (Tetrahedron: Asymmetry, 1994, 5, 1129).
- Holland, Herbert L.,Brown, Frances M.,Larsen, Brett G.,Zabic, Mirjana
-
p. 1569 - 1574
(2007/10/02)
-
- A NOVEL DECARBOXYLATION OF α-AMINO ACIDS. A FACILE METHOD OF DECARBOXYLATION BY THE USE OF 2-CYCLOHEXEN-1-ONE AS A CATALYST
-
In the presence of a catalytic amount of 2-cyclohexen-1-one, decarboxylation of α-amino acids proceeds smoothly and affords the corresponding amino compounds in good yields.Optically active amino compounds, (3R)-(-)-3-hydroxypyrrolidine and (2R)-(-)-2-hydroxypropylamine are obtained in 93percent and 80percent yields, respectively.
- Hashimoto, Mitsunori,Eda, Yutaka,Osanai, Yasutomo,Iwai, Toshiaki,Aoki, Seiichi
-
p. 893 - 896
(2007/10/02)
-
- ELECTRON SPIN RESONANCE STUDIES. PART 64. THE HYDROXYL RADICAL-INDUCED DECARBOXYLATION OF METHIONINE AND SOME RELATED COMPOUNDS
-
Spin-trapping e.s.r. experiments employing both MeNO2 (in conjunction with generation of .OH from the TiIII-H2O2 couple in a flow system) and ButNO ( in conjunction with the photolytic decomposition of H2O2) confirm that the reaction of .OH with methionine, S-methylcysteine, and some related compounds effects oxidative decarboxylation.It is proposed that the reaction proceeds via the sequential formation of an hydroxyl adduct at sulphur, a sulphur-centred radical-cation, and a (cyclic) sulphuranyl radical in which the carboxylate function becomes bonded to sulphur.
- Davies, Michael J.,Gilbert, Bruce C.,Norman, Richard O.
-
p. 731 - 738
(2007/10/02)
-
- Formation and Reduction Reactions of α-Amino Radicals Derived from Methionine and Its Derivatives in Aqueous Solutions
-
Absolute rate constants and yields have been measured for the reaction of α-amino radicals derived via an oxidative decarboxylation process from various sulfur-containing amino acids with suitable electron acceptors.The measurements were carried out with aqueous solutions and by using optical and conductivity pulse radiolysis methods.Bimolecular rate constants have been measured for the reactions of CH3SCH2CH2.CHNH2 with Fe(CN)6(3-) (k = (3.5+/-0.4)E9 M-1 s-1), C(NO2)4 (4.2+/-0.5)E9), cytochrome(III) c (6.6+/-0.6)E8), 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxy (TMPN), (5.4+/-0.5)E8), lipoate ((1-2)E8), O2 ((1.8+/-0.4)E9), p-nitroacetophenone (PNAP) ((3.9+/-0.4)E9), methylviologen (MV(2+) ((3.6+/-0.3)E9), and nicotinamide adenine dinucleotide (NAD+) ((8.5+/-3)E8).The reduction potential of this α-amino radical is more negative than -0.94 V.The protonated form CH3SCH2CH2.CHNH3(1+) reacts more slowly and k = (1.0+/-0.2)E7 and (2.3+/-0.2)E8 M-1 s-1 have been evaluated for the respective electron transfer reactions with MV(2+) and TMPN.The pK of the equilibrium CH3SCH2CH2.CHNH3(1+) = CH3SCH2CH2.CHNH2 + Haq(1+) has been determined to be 3.85.Further rate constants have been determined for hydrogen atom abstraction from cysteine by CH3SCH2CH2.CHNH2 (k>=(1-2)E9 M-1 s-1), and for the electron transfer processes CH3SCH2CH2.CHNHCOCH3 + MV(2+) (k ca. (1-2)E7 M-1 s-1), and CH3CH2CH2.CHNH2 + PNAP ( k = 4.1+/-0.4)E9) M-1 s-1).
- Hiller, K.-O.,Asmus, K.-D
-
p. 3682 - 3688
(2007/10/02)
-