Iminodicarboxylic Acid Research Articles

Improvement of catalytic activity of Candida rugosa lipase in the presence of calix[4]arene bearing iminodicarboxylic/phosphonic acid complexes modified iron oxide nanoparticles

In the present study, iron oxide magnetite nanoparticles, prepared through a co-precipitation method, were coated with phosphonic acid or iminodicarboxylic acid derivatives of calix[4]arene to modulate their surfaces with different acidic groups. Candida rugosa lipase was then directly immobilized onto the modified nanoparticles through sol–gel encapsulation. The catalytic activities and enantioselectivities of the two encapsulated lipases in the hydrolysis reaction of (R/S)-naproxen methyl ester and (R/S)-2-phenoxypropionic acid methyl ester were assessed. The results showed that the activity and enantioselectivity of the lipase were improved when the lipase was encapsulated in the presence of calixarene-based additives; the encapsulated lipase with the phosphonic acid derivative of calix[4]arene had an excellent rate of enantioselectivity against the (R/S)-naproxen methyl and (R/S)-2-phenoxypropionic acid methyl esters, with E=350 and 246, respectively, compared to the free enzyme. The encapsulated lipases (Fe-Calix-N(COOH)) and (Fe-Calix–P) showed good loading ability and little loss of enzyme activity, and the stability of the catalyst was very good; they only lost 6–11% of the enzyme’s activity after five batches.

The Ugi reaction with CF 3-carbonyl compounds: effective synthesis of α-trifluoromethyl amino acid derivatives

The Ugi reaction with CF 3-carbonyl compounds is described in detail. The method is efficient for the multicomponent preparation of α-trifluoromethyl (Tfm) amino acids, α-Tfm containing dipeptides, and iminodicarboxylic acids. In addition, the first protected CF 3-opine derivative was prepared. The scope, limitations, and stereochemistry of the approach are discussed.

Asymmetric syntheses of N-substituted α-amino esters via dynamic kinetic resolution of α-haloacyl diacetone-d-glucose

Abstract Diacetone- d -glucose or d -allose mediated dynamic kinetic resolution of α-halo esters in nucleophilic substitution reaction has been investigated. Reactions with various amine nucleophiles in the presence of TBAI and DIEA can provide the N -substituted α-amino esters up to 99:1 dr. Stereochemical models of transition states, taking into account a hydrogen bonding, are proposed on the basis of the observed results. Also, application of this mild and simple methodology to stereoselective preparations of 1,1′-iminodicarboxylic acid derivatives is demonstrated.

Dynamic Kinetic Resolution of α‐Bromo Carboxylic Acid Derivatives in Asymmetric Nucleophilic Substitution with Chiral α‐Amino Esters.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Dynamic Kinetic Resolution of α-Bromo Carboxylic Acid Derivatives in Asymmetric Nucleophilic Substitution with Chiral α-Amino Esters

Dynamic kinetic resolution of -bromo carboxylic acid derivatives in nucleophilic substitution with chiral -amino ester nucleophiles in the presence of TBAI and DIEA has been investigated for stereoselective syntheses of 1,1'-iminodicarboxylic acid derivatives. Nucleophilic substitutions with various chiral -amino esters gave iminodiacetates 2-8 with stereoselectivities up to 87 : 13 dr. Also, the reactions of N-(-bromo--phenylacetyl)-L-alanine methyl ester with L-alanine, D-alanine and glycine methyl ester nucleophiles afforded N-carboxyalkyl dipeptide analogues 10-12 up to 90 : 10 dr.�⨀ԀĀ衺�⨀ԀĀऐ돀졽�⨀堘�⨀ꢐ�⨀돐좐�⨀��⨀킐�⨀뤏덐�⨀렏頏࢑�⨀਀࢑�⨀ᢑ�⨀؀ကᢑ�⨀?麆Ѐက䂑�⨀䂑�⨀

Iminodicarboxylic acids in the Murchison meteorite: Evidence of Strecker reactions

α-Amino acids and α-hydroxy acids are well known constituents of several carbonaceous meteorites. One proposed mechanism of their formation is the reactions of CN −, NH 3, aldehydes and ketones in aqueous solution, a Strecker-like synthesis. Iminodicarboxylic acids, relatively unusual in molecular structure, are significant by-products of laboratory Strecker syntheses of α-amino acids. It is therefore notable that an analogous suite of imino acids has not been reported in CM2 chondrites where amino and hydroxy acids are abundant. In this work, aqueous extracts of the Murchison meteorite were examined for the presence of imino acids; GC-MS and HPLC molecular analyses revealed a complex suite of such acids. With the exception of one of the seven-carbon members, all of the C4 through C7 imino acids were observed in Murchison. These observations suggest that the Strecker synthesis made, at least, some contribution to the formation of extraterrestrial amino acids.

Formation of 1,1 ′-iminodicarboxylic acid derivatives, 2,6-diketo-piperazine and dibenzodiazocine-2,6-dione by variations of multicomponent reactions

The combination of multicomponent reactions (MCRs) of different amino acids, aldehydes, isocyanides and acids allows complex structures to be prepared in one-pot reactions. The synthesis of 1,1 ′-iminodicarboxylic acid derivatives 12 demonstrates the high selectivity of the Ugi Four Component Reaction using two different aldehydes and two different isocyanides. The limitations of the MCRs are illustrated by the synthesis of a 1,1 ′-iminodicarboxylic acid derivative 6 from l-lysine. Furthermore, 2,6-diketopiperazines and dibenzodiazocin-2,6-diones are synthesized via MCRs.

Ugi reactions with trifunctional α-amino acids, aldehydes, isocyanides and alcohols

1,1′-iminodicarboxylic acid derivatives, which are similar to many natural substances can be synthesized in excellent yields and with high stereoselectivity by a one-pot reaction of α-amino acids, aldehydes, isocyanides and alcohols.

ChemInform Abstract: Synthesis of Chiral 1,1′‐Iminodicarboxylic Acid Derivatives from . alpha.‐Amino Acids, Aldehydes, Isocyanides, and Alcohols by the Diastereoselective Five‐Center‐Four‐Component Reaction.

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Synthesis of Chiral 1,1′‐Iminodicarboxylic Acid Derivatives from α‐Amino Acids, Aldehydes, Isocyanides, and Alcohols by the Diastereoselective Five‐Center–Four‐Component Reaction

Synthesis of Chiral 1,1′‐Iminodicarboxylic Acid Derivatives from α‐Amino Acids, Aldehydes, Isocyanides, and Alcohols by the Diastereoselective Five‐Center–Four‐Component Reaction

ChemInform Abstract: Synthesis of Peptides Containing α,α′‐Iminodicarboxylic Acids.

AbstractThe peptides (V) containing an α,α'‐iminodicarboxylic acid unit are obtained by the four‐component Ugi condensation reaction of the N‐protected amino acids (I), the amino esters (II), isobutyraldehyde (III), and tosylmethyl isocyanide (IV).

Synthesis of Peptides Containing α,α′-Iminodicarboxylic Acids

Abstract The peptides containing α,α′-iminodicarboxylic acids which are hardly prepared by the conventional methods of peptide synthesis, were well synthesized by the four-component condensation. The diastereomers were isolated, and their configurations were determined.

ChemInform Abstract: Amino Acids. Part 5. Stereoselective Synthesis of α,α′‐Imino Dicarboxylic Acids.

AbstractDie verschieden konfigurierten Trifluormethansulfonate (Ia)‐(Id) bzw. (Ie) [in situ aus der Vorstufe (IV)] reagieren mit (S)‐ bzw. (R)‐Aminosäureestern (II) diaste‐ 169 reoselektiv zu den entsprechenden Iminodicarbonsäureestern (III) bzw. (VI), wobei am chiralen Zentrum jeweils eine Konfigurationsumkehr erfolgt (die einzelnen Produkte sind in mehreren Tabellen zusammengefaßt).

Gas Chromatography–Mass Spectrometry of N-Trifluoroacetyl Trimethylsilyl Esters of Some Iminodicarboxylic Acids

Abstract The simultaneous N-trifluoroacetylation and O-trimethylsilylation of some iminodicarboxylic acids were studied by the use of a mixture of α,α,α,α′,α′,α′-hexafluoro-N-methyldiacetamide and N,O-bis(trimethylsilyl)trifluoroacetamide, as a derivatizing reagent. The resulting N-trifluoroacetyl trimethylsilyl ester derivatives gave rather complicated mass spectra with molecular (M+) and M–15 (loss of CH3) ions upon electron impact at 20 eV.

Gas Chromatography–Mass Spectrometry of Trimethylsilyl Derivatives of Some Iminodicarboxylic Acids

Abstract Trimethylsilylation of eight iminodicarboxylic acids (IDCAs) with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) or N,O-bis(trimethylsilyl)acetamide was studied under various reaction conditions. The IDCAs include iminodiacetic acid (1), 2- and 3-(carboxymethylamino)propionic acids (2 and 3), 2,2′-, 2,3′-, and 3,3′-iminodipropionic acids (4–6), N-methyliminodiacetic acid (7), and nitrilotriacetic acid (8). For 1–6, both bis- and tris(trimethylsilyl) (TMS) derivatives were formed under usual silylating conditions, although the proportion of amounts of the two derivatives varied depending on reaction conditions. This double derivatization was due to the steric hindrance of N-substituent group. However, under mild silylating conditions (BSTFA alone, 120 °C, 30 min), 1–6 yielded only the di-TMS derivatives. Upon electron impact at 20 eV, both the di- and tri-TMS derivatives showed simple spectra with a molecular (M+) ion and M −15 (loss of CH3). The α,α′-IDCAs (1, 2, 4, 7, and 8) are characterized by fragments M −43 (loss of CH3 and CO) and M −117 (loss of COOTMS) (base peak). On the other hand, the β,β′-IDCA (6) is characterized by fragments M −57 (loss of CH3, CH2, and CO) and prominent M −131 (loss of CH2COOTMS). The α,β′-IDCAs (3 and 5) exhibit both the fragments characteristic of α,α′- and β,β′-IDCAs, M −43, M −57, M −117, and M −131. However, base beaks are usually the fragment M −117 and not M −131.

Mass Spectra of Butyl Esters and N-Trifluoroacetyl Butyl Esters of Some Iminodicarboxylic Acids upon Electron Impact

Abstract Mass spectra (electron impact at 20 eV) of butyl esters and N-trifluoroacetyl (TFA) butyl esters of some iminodicarboxylic acids (IDCAs) were determined by gas chromatography-mass spectrometry. The IDCAs included iminodiacetic acid (1), 2-(carboxymethylamino)propionic acid (2), 3-(carboxymethylamino)propionic acid (3), 2,2′-iminodipropionic acid (4), 2,3′-iminodipropionic acid (5), 3,3′-iminodipropionic acid (6), N-methyliminodiacetic acid (7), and nitrilotriacetic acid (8). The mass spectra of the butyl ester derivatives are simple, exhibiting the corresponding molecular (M+) ions with the exception of 5. The α,α′-IDCAs (1, 2, 4, 7, and 8) are characterized by M+, M −101 (COOC4H9) (base peak), and M −157 (COOC4H9+C4H8) ions. The β,β′-IDCA (6) is characterized by a more complex spectrum with M+, M −73 (OC4H9), M −115 (CH2COOC4H9) (base peak), M −129 (OC4H9+C4H9), and M −171 (CH2COOC4H9+C4H9) ions. The α,β′-IDCAs (3 and 5) in general show spectra in which both ions characteristic of α,α′- and β,β′-IDCAs are observed. The addition of TFA to the imino nitrogens of 1–6 increases complexity of the resulting spectra. In these instances, although M+ ions are usually present, neither M −101 nor M −115 ions are base peaks. The fragmentation pathways of these two volatile derivatives of the IDCAs upon electron impact are discussed.

Studies on Tetrachloroalkane Derivatives.

Ammonolysis of ω-chloroenanthic acid and ω-chloropelargonic acid was carried out in the presence of 25% aqueous ammonia + ammonium salt. When ammonium carbonate was comployed, the yield of ω-aminocarboxylic acid was good with the lower mole ratio of ammonia/ω-chlorocarboxylic acid and by-product (mainly ω, ω'-iminodicarboxylic acid) was small amount. For increasing the mole concentration of ammonia in liquid phase, using of as much as possible of larger volume ratio (vol. of total raw materials in the autoclave/capacity of autoclave) and adjusting of suitable reaction velocity gave better result when the reaction was carried out at lower temperature.

Triazine isocyanates: Part II: Reaction of 2,4‐diamino‐s‐triazines with ethyl chlorocarbonate

AbstractBenzoguanamine (2,4‐diamino‐6‐phenyl‐s‐triazine) and acetoguanamine (2,4‐diamino‐6‐methyl‐s‐triazine) both react with an excess of ethyl chlorocarbonate; in this reaction two hydrogen atoms from the guanamines are replaced by two carbethoxy groups. The I.R. spectrum reveals that this double substitution takes place on one amino group; in consequence, the resulting compounds are derivatives of iminodicarboxylic acid diethyl ester. Upon heating above the melting point, the compounds decompose, during which process a very short occurrence of isocyanate absorption can be observed in the I.R. spectrum.

?,??-imino dicarboxylic acids and some of their derivatives

Starting from the correspondingω-chloro carboxylic acids we preparedω,ω′ -imino dicarboxylic acids and their N- and O- derivatives; the products had the following structures: