NMR Determination of absolute configurations in 2‐alkylthiazolidine‐4‐carboxylic acids

Restelli, A.; Annunziata, Rita; Pellacini, F.; Ferrario, F.

doi:10.1002/jhet.5570270442

Cited by 14 publications

(9 citation statements)

References 17 publications

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“…1 H-1 H nuclear overhauser effect has been widely used to determine molecular structures in solution. 16 In the case of thiazolidines, the NOE experiments showed an H(4) to H(2) correlation which was adequate for determining the cis : trans configuration (Figure 4). Thus, the 2D NOESY spectrum of the methyl 2-methylthiazolidine-4-(R)-carboxylates C : D (Figure 4) shows the interaction between H(2) and H(4) for the major isomer, C, while the H(4) proton is only correlated with H(5) in the minor isomer, D. The space-proximity of H(2) and H(4) protons in C gives evidence for a cis configuration of the ester and the R 2 groups in the thiazolidine ring ( Figure 5).…”

mentioning

confidence: 96%

Identification of thiazolidines in guava: stereochemical studies

Fernández¹,

Duñach²,

Fellous³

et al. 2001

Flavour & Fragrance J

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Volatile compounds from guava (Psidium guajava L.) were extracted using dichloromethane. Among these volatile compounds, methyl 2-methyl-thiazolidine-4-(R)-carboxylate (cis and trans) and the ethyl 2-methyl-thiazolidine-4-(R)-carboxylate (cis and trans) could be identified for the first time in fruits. The chemical synthesis of the reference compounds and other analogues allowed the further comparison with the guava extracted thiazolidines. The absolute configuration of the cis/trans isomers was determined by nuclear magnetic resonance ( 1 H-NMR) and by nuclear overhauser enhancement (2D NMR NOESY).

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mentioning

confidence: 96%

Identification of thiazolidines in guava: stereochemical studies

Fernández¹,

Duñach²,

Fellous³

et al. 2001

Flavour & Fragrance J

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“…A three-stage decomposition pattern was observed with the thermograms of Cu(II) complexes; the first stage involved loss of lattice water molecules at 70 -120°C, and the next stages involved loss of C 5 H 10 molecule at 200 -315°C and CO 2 molecule at 210 -325°C for CuL 2 and CuL 1 , respectively. The third phase of the decomposition pattern of CuL 1 demonstrated losses of C 3 H 5 at 325-680 o C, whereas the CuL 2 decomposition pattern demonstrated losses of 2NH 2 at 307-680 o C.…”

Section: Thermogravimetric Analysis and Molar Conductivitymentioning

confidence: 97%

“…Thiazolidine-4-carboxylic acid (THC), also known as thioproline, can be defined as cyclic sulphur containing amino acid, and can be easily synthesized by the reaction of L-cysteine with aromatic or aliphatic aldehydes [1][2][3][4]. This reaction yielded (2S,4R)-and (2R,4R)diastereomer mixture.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, thiazolidine-4-carboxylic acid allows restoring "contact inhibition" pertaining to tumour cells and its interaction with metal ions is regarded to be of key significance [9,10]. The derivatives pertaining to 2-substituted thiazolidine -4-carboxylic acids find application as key intermediates in peptide synthesis [11], as well as preparation of antiviral [2], microencapsulated liposomal and immunostimulating biological drugs [7,12].…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, Antibacterial Activity and DFT Calculations of Some Thiazolidine-4-Carboxylic acid Derivatives and Their Complexes with Cu(II), Fe(II) and VO(II)

2020

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T HE reaction of L-Cysteine with 2-hydroxy naphthaldehyde and 2-hydroxy benzaldehyde yields novel bidentate ligands (2R,4R)-2-(2-hydroxynaphthalen-1-yl) thiazolidine-4carboxylic acid (L 2) and (2R,4R)-2-(2-hydroxyphenyl) thiazolidine-4-carboxylic acid (L 1), respectively, which can be characterised based on spectral and physical data. Synthesis of complexes with the formula ML 2 .XH 2 O is done via the reaction of L 1 and L 2 with Cu(II), Fe(II) and VO(II) in molar ratio of 1:2 pertaining to metal to ligand. Based on mass and UV/ visible spectra, IR, flame atomic absorption, magnetic susceptibility as well as thermal analysis of metal complexes, we can conclude that the ligands behave as a bidentate and help to identify proper structure pertaining to complexes. Then, screening of the synthesized compounds is carried out to determine their antibacterial activity against Pseudomonas aeruginosa and Streptococcus epidermis. All compounds showed bio-activity with iron complexes possessing the highest efficiency. The density functional theory at the B3LYP level of theory was employed to calculate the geometry optimisation pertaining to molecular structure as well as energies of ligands and its associated complexes. The observations of the theoretical calculations were in line with the outcomes of the experiment.

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“…A considerable interest in the chemistry [7] and pharmacology of thiazolidine derivatives [8,9] stimulates studies on the synthesis of new compounds of this series. 2-Alkyl-1,3-thiazolidines are especially important, for they exhibit radioprotective and antimutagenic activity [6].…”

mentioning

confidence: 99%

Reaction of 2-Alkoxypropenals with 2-Aminoethanethiol and Ring-Chain Tautomerism of the Resulting 2-(1-Alkoxyvinyl)-1,3-thiazolidines

et al. 2005

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2-Alkoxypropenals react with 2-aminoethanethiol to give tautomeric mixtures of the corresponding 2-(1-alkoxyvinyl)-1,3-thiazolidines and 2-(2-alkoxy-2-propenylideneamino)ethanethiols in quantitative yield. The state of the ring-chain tautomeric equilibrium depends on the polarity and acidity of the medium and initial reactant ratio, and it does not change on raising the temperature and is only slightly affected by microwave irradiation.Functionalized thiols, such as 2-sulfanylethanol [1] and 1,2-and 1,3-dithiols [2], are known to add to 2-alkoxypropenals in neutral medium according to the Markownikoff rule to give methylglyoxal O,S-acetals. However, in the presence of bases (K 2 CO 3 , Et 3 N) the addition of thiols to 2-alkoxypropenals occurs at the 1,4-positions with formation of 3-alkylsulfanyl-2-alkoxypropanals in 75-100% yield [3]. Primary amines react with 2-ethoxypropenal to afford Schiff bases [4]; as noted in [5], in the reaction of acrolein with nucleosides, the primary amino groups of cytosine and thymine can add to the 1,4-position. The above data suggest that nucleophilic attack on 2-alkoxypropenal can be directed at the double C=C bond or aldehyde group, depending on the nucleophile nature, catalyst, and reaction medium.The goal of the present work was to elucidate regioand chemoselectivity in the addition of a difunctional nucleophile, 2-aminoethanethiol (cysteamine [6]), to 2-alkoxypropenals, depending on the reaction conditions (solvent nature, polarity and acidity of the medium, temperature, microwave activation) and to study ring-chain tautomerism of the resulting Schiff bases and thiazolidines. A considerable interest in the chemistry [7] and pharmacology of thiazolidine derivatives [8,9] stimulates studies on the synthesis of new compounds of this series. 2-Alkyl-1,3-thiazolidines are especially important, for they exhibit radioprotective and antimutagenic activity [6]. Furthermore, thiazolidine ring is a structural fragment of a number of natural compounds and biologically active substances [10]; therefore, studies on the dynamics of ring-chain equilibrium of thiazolidine derivatives are important for understanding biochemical processes [11].The reactions of 2-alkoxypropenals Ia and Ib with 2-aminoethanethiol (II) were expected to follow pathway a (Scheme 1) which involves 1,2-addition of the amino group. Elimination of water from intermediate A could give rise to vinylthiazolidine III or Schiff base IV. Isomers III and IV are interconvertible; it is known that even in neutral aqueous medium thiazolidine ring exists in equilibrium with the open-chain iminothiol structure [12] or initial reagents (from which it was synthesized) [13]. An alternative initial stage is sometimes considered to be attack on the carbonyl carbon atom by the SH group of 2-aminoethanethiol with formation of monothio semiacetals (pathway b) [14]. This reaction sequence was observed in reactions of α,β-unsaturated ketones with β-amino thiols [15]. By analogy with the data of [3], one more reaction pathway may be 1,4-addi...

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NMR Determination of absolute configurations in 2‐alkylthiazolidine‐4‐carboxylic acids

Cited by 14 publications

References 17 publications

Identification of thiazolidines in guava: stereochemical studies

Identification of thiazolidines in guava: stereochemical studies

Synthesis, Antibacterial Activity and DFT Calculations of Some Thiazolidine-4-Carboxylic acid Derivatives and Their Complexes with Cu(II), Fe(II) and VO(II)

Reaction of 2-Alkoxypropenals with 2-Aminoethanethiol and Ring-Chain Tautomerism of the Resulting 2-(1-Alkoxyvinyl)-1,3-thiazolidines

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