Dimethyl Tartrate Research Articles

New tartrate and α-tocopherol based environmentally friendly plasticizers for improvement of the ductility of polylactic acid

This study focuses on developing environmentally friendly plasticized poly(lactide) (PLA) formulations using tartaric acid and α-tocopherol at 20 wt%. The extrusion and injection molding processes demonstrated the industrial applicability of these plasticizers. Mechanical tests revealed positive results for tartrate-based plasticizers, with elongation at break surpassing 220 %, while α-tocopherol succinate achieved 170 %. However, α-tocopherol acetate showed limited PLA plasticization. Field emission scanning electron microscopy confirmed plasticization in fractured surfaces. Thermal analysis indicated a reduction in PLA's glass transition temperature (Tg) from 60 °C to around 30 °C with these plasticizers, underscoring tartrates' exceptional efficiency. The cold crystallization temperature (Tcc) decreased for all plasticized samples due to enhanced chain mobility. Thermomechanical analysis revealed dimensional shrinkage, with dimethyl tartrate (DMT) causing less pronounced effects. Generally, tartrates yielded formulations with superior properties, attributed to their lower molecular weight compared to α-tocopherol-derived plasticizers. Notably, all plasticizers employed are an eco-friendly approach to improve PLA's processability and enhancing ductile properties.

Alkylation of lithiated dimethyl tartrate acetonide with unactivated alkyl halides and application to an asymmetric synthesis of the 2,8-dioxabicyclo[3.2.1]octane core of squalestatins/zaragozic acids.

(R,R)-Dimethyl tartrate acetonide 7 in THF/HMPA undergoes deprotonation with LDA and reaction at −78 °C during 12–72 h with a range of alkyl halides, including non-activated substrates, to give single diastereomers (at the acetonide) of monoalkylated tartrates 17, 24, 33a–f, 38a,b, 41 of R,R-configuration, i.e., a stereoretentive process (13–78% yields). Separable trans-dialkylated tartrates 34a–f can be co-produced in small amounts (9–14%) under these conditions, and likely arise from the achiral dienolate 36 of tartrate 7. Enolate oxidation and acetonide removal from γ-silyloxyalkyl iodide-derived alkylated tartrates 17 and 24 give ketones 21 and 26 and then Bamford–Stevens-derived diazoesters 23 and 27, respectively. Only triethylsilyl-protected diazoester 27 proved viable to deliver a diazoketone 28. The latter underwent stereoselective carbonyl ylide formation–cycloaddition with methyl glyoxylate and acid-catalysed rearrangement of the resulting cycloadduct 29, to give the 3,4,5-tricarboxylate-2,8-dioxabicyclo[3.2.1]octane core 31 of squalestatins/zaragozic acids. Furthermore, monoalkylated tartrates 33a,d,f, and 38a on reaction with NaOMe in MeOH at reflux favour (≈75:25) the cis-diester epimers epi-33a,d,f and epi-38a (54–67% isolated yields), possessing the R,S-configuration found in several monoalkylated tartaric acid motif-containing natural products.

ChemInform Abstract: Total Synthesis of (—)‐Stemoamide by Sequential Overman/Claisen Rearrangement.

AbstractThe enantioselective total synthesis of (—)‐stemoamide using Overman/Claisen rearrangement of an allylic 1,2‐diol is reported.

Total Synthesis of (–)-Stemoamide by Sequential Overman/Claisen Rearrangement

The enantioselective total synthesis of (–)-stemoamide using Overman/Claisen rearrangement of an allylic 1,2-diol is reported. The enantiopure allylic 1,2-diol was efficiently prepared from naturally occurring dimethyl tartrate. The chirality transfer reactions through two consecutive [3,3]-sigmatropic rearrangements proceeded with complete diastereoselectivity in a one-pot process.

Synthesis of azide derivative and discovery of glyoxalase pathway inhibitor against pathogenic bacteria

A glyoxalase inhibitor was synthesized and tested against Staphylococcus aureus for first time and showed MIC90 of 20μg/ml. Henceforth, we synthesized unnatural azide derivative of the same inhibitor to improve the biological activity. In that order, an azide carboxylate was synthesized from dimethyl tartrate by tosylation and azide substitution. The synthesized, azide compound was coupled with glutathione derivative in high yield and tested against S. aureus and showed improved MIC90 of 5μg/ml. In general, it can be also easily converted to unnatural β-amino acid in good yield. The shown methodology will be extended to study induced suicide in Burkholderia mallei, Francisella tularensis and Mycobacterium tuberculosis in future.

ChemInform Abstract: Regio‐ and Stereoselective Approach to 1,4‐Ditertiary Carbinols from Dimethyl Tartrate.

AbstractStarting from (I), convenient syntheses for accessing differently substituted tetrahydroxy compounds in a stereoselective fashion are described.

Regio- and Stereoselective Approach to 1,4-Ditertiary Carbinols from Dimethyl Tartrate

A rational strategy for accessing tetrahydroxy compounds in predictable stereoselective fashion from di-O-benzyl protected tartrate is presented. Up to four different aromatic, aliphatic, and vinyl substituents could be stepwise introduced at C1 and C4. This is exemplified in an economic preparation of eight dihydroxy compounds from natural tartaric acid in six steps and 19–59% overall yield. A final deprotection step afforded the corresponding tetrahydroxy compounds in good yields.

Investigations of methyl lactate in the presence of reverse micelles by vibrational spectroscopy and circular dichroism

The FT-IR and vibrational circular dichroism (VCD) spectra of (S)- and -(R)-methyl lactate have been recorded for neat samples and at various concentrations in CCl4 and DMSO solutions. These spectra are used to analyse the FT-IR and VCD spectra of methyl lactates in presence of sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in CCl4, where the surfactant molecules are known to form reverse micelles. Some tendency of methyl lactate to interact with AOT micellar aggregates is observed, but not as well defined as previously observed for dimethyl tartrate in analogous circumstances. Besides, near infrared (NIR) absorption and VCD data have been obtained for most of the above systems, allowing to monitor the first overtone of the OH-stretching vibration of methyl lactates, especially in the spectroscopic region where the OH bond is not involved in hydrogen bond with other molecules. The NIR absorption and NIR VCD data for dilute solutions are reproduced and interpreted by anharmonic DFT calculations. Further understanding of the behavior of aggregated methyl lactate systems has been gained on this basis.

Synthesis of a Novel Benzoyl Adenosine Analog Containing a 1, 4-Dioxane Sugar Analog and the Synthesis of a Corresponding Uracil Adenine Dinucleotide

Adenosine analogs in which the sugar unit was replaced by a 1,4-dioxane sugar equivalent, were prepared by coupling the 1,4-dioxane sugar analog as its anomeric acetates, with N6-benzoyl protected adenine. The 1,4-dioxane system was obtained in an enantioselective synthesis from (R,R)-dimethyl tartrate. Using standard phosphorimidite methodology, the adenine analog was further reacted with a 1,4-dioxane uridine analog to give the corresponding, protected dinucleotide, set-up for further condensation into larger oligonucleotides.

DIBAL-Mediated Reductive Transformation of trans-Dimethyl Tartrate Acetonide into ε-Hydroxy α,β-Unsaturated Ester and Its Derivatives

Stepwise, selective DIBAL reduction of the acetonide diester derived from tartaric acid followed by the Horner-Emmons reaction effectively provided desymmetrized hydroxy mono-olefination products in a one-pot operation.

(+)-Dimethyl tartrate in the synthesis of optically active bis-arylphosphonodithioic acids

(+)-Dimethyl tartrate in the synthesis of optically active bis-arylphosphonodithioic acids

ChemInform Abstract: Synthesis of Chiral Nonracemic Diols via Nucleophilic Opening of (S,S)- 1,2,3,4-Diepoxybutane.

Abstract (S,S)-1,2,3,4-diepoxybutane was synthesized from (R,R)-dimethyl tartrate. Nucleophilic opening of this diepoxybutane gave a convenient method for generating a variety of chiral nonracemic diols.

ChemInform Abstract: Stereoselective Opening of Acetals Derived from Dimethyl Tartrate.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Cyclic Ketals of Tartaric Acid: Simple and Tunable Reagents for the Determination of the Absolute Configuration of Primary Amines

2,2-Diphenyl-[1,3]dioxolane-4,5-dicarboxylic acid (DPD) and 2,2-dinaphthalen-2-yl-[1,3]dioxolane-4,5-dicarboxylic acid (DND) have been synthesized starting from dimethyl tartrate. DPD and DND amides of alpha-chiral primary amines showed significantly different (1)H chemical shift values depending on the stereochemistry of the derivatizing agent. On the basis of this chemical shift difference, the absolute configuration of amine substrates could be assigned. DND amides showed significantly larger chemical shift differences than the corresponding DPD amides allowing for a more error-free assignment.

Modification of chiral dimethyl tartrate through transesterification: Immobilization on POSS and enantioselectivity reversal in sharpless asymmetric epoxidation

Modification of dimethyl tartrate has been investigated through transesterification with aminoalcohols to provide reactive functionalities for the covalent bonding of chiral tartrate to polyhedral oligomeric silsesquioxanes. The transesterification of dimethyl tartrate has been widely studied using different catalytic systems and reaction conditions. Through the proper selection of both the catalytic system and the reaction conditions, it is possible to achieve monosubstituted or bis-substituted tartrate derivatives as sole products. All the intermediate chiral tartrate-derived ligands were successfully used in the homogeneous enantioselective epoxidation of allylic alcohols providing moderate enantiomeric excess over the products. Attached amine groups have been used to support the modified tartrate ligands on to a haloaryl-functionalized silsesquioxane moiety. This final chiral tartrate ligand displays reverse enantioselectivity in the asymmetric epoxidation of allylic alcohols with regard to the starting dimethyl tartrate ligand, both molecules having the same chiral sign. However, the POSS-containing ligand can be easily recovered in almost quantitative yield and reused in asymmetric epoxidation reactions. In addition, recovered silsesquioxane-pendant ligand, though displaying decreasing catalytic activity in recycling epoxidation tests, showed very stable enantioselective behavior.

ChemInform Abstract: Synthesis of Vulpinic Acids from Dimethyl Tartrate.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of vulpinic acids from dimethyl tartrate

A series of vulpinic acids differing by the aryl or heteroaryl groups placed in the ester α-position were prepared by Suzuki–Miyaura cross-coupling involving a common iodide and the corresponding aryl boronates. The preparation of the iodide precursor from (+)-dimethyl l-tartrate required four steps: the esterification of one hydroxyl group, a Dieckmann cyclization allowing the construction of the tetronic acid moiety, a dehydration leading to the installation of the exocyclic double bond and lastly, an N-iodosuccinimide-mediated iodation of the alkene obtained.

Spectroscopic and Structural Investigation of the Confinement of d and l Dimethyl Tartrate in Lecithin Reverse Micelles

The confinement of D and L dimethyl tartrate in lecithin reverse micelles dispersed in cyclohexane has been investigated by FT-IR, polarimetry, electronic and vibrational circular dichroism (ECD and VCD), 1H NMR, and small-angle X-ray scattering (SAXS). Measurements have been performed at room temperature as a function of the solubilizate-to-surfactant molar ratio (R) at fixed lecithin concentration. The analysis of experimental data indicates that the dimethyl tartrate molecules are solubilized within reverse micelles in proximity to the surfactant head groups in the same way for the D and L forms. The encapsulation of dimethyl tatrate within lecithin reverse micelles involves changes in its H-bonds, from what is observed in the pure solid or in CCl4 solutions; this is a consequence of the establishment of specific solute-surfactant headgroup interactions and of confinement effects. In the 0 < or = R < or = 1.7 range, SAXS profiles of dimethyl tartrate/lecithin/ cyclohexane micellar solutions are well-described by a model of interacting polydisperse spherical micellar cores whose mean radius does not change appreciably with R (i.e., it changes from about 18 to 20 angstroms). 1H NMR diffusion measurements of both dimethyl tartrates and lecithin were rationalized in terms of collective translational motions of the entire micellar aggregate and of their molecular diffusion among clusters of reverse micelles. The association of optically active lecithin with D and L dimethyl tartrate leads to the formation of self-organized supramolecular aggregates whose interesting chiroptical features are evidenced by polarimetry and CD.

Na(I) binding by tartaric acid derivatives

A study of the binding of Na + by two readily available tartaric acid derivatives, dimethyl tartrate and dipyrrolidine tartramide, has been carried out. These binding studies reveal binding stoichiometries of 1:1 for the dimethyl tartrate and 2:1 for the dipyrrolidine tartramide, and binding affinities (association constants) of 6.61 M −1 for the dimethyl tartrate and 70.4 M −2 for the dipyrrolidine tartramide indicating weak binding of Na + in both cases. An X-ray crystal structure of a NaI complex of dipyrrolidine tartramide has also been determined. The binding stoichiometry is 1:1 in the solid state as opposed to the 2:1 binding stoichiometry that is observed in solution. The 1:1 binding in the solid state results in a coordination polymer in which half of the carbonyl oxygens and half of the hydroxy oxygens of the dipyrrolidine tartramide ligand bridge between adjacent Na + cations. This allows each Na + cation to achieve an octahedral coordination geometry. The iodides are ordered in a linear fashion, and each column of iodides is separated from the other columns by the coordination polymer and by linear columns of water molecules.

Synthesis of Novel Homo-N-Nucleoside Analogs Composed of a Homo-1,4-Dioxane Sugar Analog and Substituted 1,3,5-Triazine Base Equivalents

Enantioselective syntheses from dimethyl tartrate of 1,3,5-triazine homo-N-nucleoside analogs, containing a 1,4-dioxane moiety replacing the sugar unit in natural nucleosides, were accomplished. The triazine heterocycle in the nucleoside analogs was further substituted with combinations of NH2, OH and Cl in the 2,4-triazine positions.