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Application of two coformers, l-tartaric acid (TA) and ascorbic acid (AA) was evaluated on the solubility of pioglitazone hydrochloride (PGZ.HCl). Solid dispersions were prepared using the solvent evaporation method. Drug solubility was evaluated in bio-relevant media and the results were compared to the physical mixtures (PM) of the drug + coformer, and the pure drug. Physicochemical characterisation of the developed products was characterised using Fourier transformation-infrared spectroscopy (FT-IR), Differential scanning calorimeter (DSC), and X-ray powder diffractometry (XPRD). Physical mixtures of PGZ-AA (PM) were able to enhance drug solubility to the same extent as the solvent evaporation method (PGZ-AA). This indicates that the preparation process has little effect on drug solubility. Up to 7-fold enhancement was observed for drug solubility in distilled water and buffer pH 1.2. Physical mixtures seem more feasible method to significantly enhance drug solubility without the need to use toxic solvents and time-consuming evaporation methods. [ABSTRACT FROM AUTHOR]

A novel approach for synthesis of Cobimetinib was reported, avoiding usage of a strong base in any of the steps with a chiral substrate. An efficient kinetic resolution of racemic key intermediate - tert-butyl 2-(3-hydroxyazetidin-3-yl)piperidine-1-carboxylate with L-tartaric acid was developed, by which enantiopure S-enantiomer was obtained as the corresponding diastereomeric tartrate salt, followed by peptide coupling with 3,4-difluoro-2-(2-fluoro-4-iodo-anilino) benzoic acid in mild conditions and avoiding the use of corresponding haloanhydrides, affording Boc-protected Cobimetinib. In the end, Cobimetinib was obtained in a total yield of 28.2%, calculated based on the S-enantiomer of the racemic key intermediate, via acid-mediated removal of Boc-protective group. [ABSTRACT FROM AUTHOR]

Binary mixtures of active pharmaceutical ingredients (API) are researched to improve the oral bioavailability of pharmaceutical dosage forms. The purpose of this study was to obtain mixtures of meloxicam and L-tartaric acid because tartaric acid improves intestinal absorption and meloxicam is more soluble in a weakly basic environment. The mixtures in the 0–1 molar fraction range, obtained from solvent-assisted mechanosynthesis, were investigated by differential scanning calorimetry (DSC), Fourier Transform Infrared (FTIR) spectroscopy, Fourier Transform Raman spectroscopy (FT-Raman), X-ray powder diffraction (XRD) and solubility tests. The physicochemical characteristics of the compounds obtained from DSC data reveal, for the first time, the formation of a co-crystal at meloxicam molar fraction of 0.5. FTIR spectroscopy data show the existence of hydrogen bonds between the co-crystal components meloxicam and L-tartaric acid. FT-Raman spectroscopy was used complementary with FT-IR spectroscopy to analyze the pure APIs and their mixtures, to emphasize the appearance/disappearance and the shifts of the position/intensity of vibrational bands, following the formation of hydrogen-bonded structures or van der Waals interactions, and to especially monitor the crystal lattice vibrations below 400 cm−1. The experimental results obtained by X-ray powder diffraction confirmed the formation of the co-crystal by the loss and, respectively, the apparition of peaks from the single components in the co-crystal diffractogram. The solubility tests showed that the co-crystal product has a lower aqueous solubility due to the acidic character of the other component, tartaric acid. However, when the solubility tests were performed in buffer solution of pH 7.4, the solubility of meloxicam from the co-crystal mixture was increased by 57% compared to that of pure meloxicam. In conclusion, the studied API mixtures may be considered potential biomaterials for improved drug release molecular solids. [ABSTRACT FROM AUTHOR]

This work presents the application of L-tartaric acid (L-TA), ascorbic acid (AA), and L-carnitine (L-CAR) as a safe and non-toxic alternative agent to enhance the aqueous solubility of baclofen (BAC). The solvent evaporation method was employed for co-crystallization in three stoichiometric ratios of the drug, coformer (1:1, 1:3, 1:5) and formulations were confirmed by X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FT-IR). DSC study revealed the presence of both endothermic and exothermic peaks in compounds containing AA and L-TA. With respect to the BAC, L-TA and BAC, AA, the appearance of new diffraction peaks that do not overlap with un-processed BAC may be the implication of a new structure. The intensity of some diffraction peaks disappeared or reduced significantly which may also imply the formation of a new crystal phase. The solubility of the multicomponents increased and surpassed the solubility of BAC. Overall, the new compounds show significantly higher drug solubility whereas their physical mixtures only demonstrate a marginal increase in BAC solubility. The high solubility records of BAC, AA and BAC, L-TA evidence the marked difference in solubility of the new compounds with respect to their physical mixtures. The saturation solubility of BAC, L-CAR compound did not show any improvement relative to the un-processed BAC. These findings confirm that a new crystal phase may not have been obtained during the co-crystallization of BAC and L-CAR. [ABSTRACT FROM AUTHOR]

The authors of the title paper (Appl Phys A127 496 (2021)) claim to have synthesized a “mixture of potassium hydrogen phthalate and l‑tartaric acid” crystal by a slow evaporation of an aqueous solution containing equimolar amounts of potassium hydrogen phthalate (KHP) and l‑tartaric acid. In this comment, many points of criticism, concerning the synthesis of the title crystal and its characterization, are highlighted to show that a so-called “mixture of potassium hydrogen phthalate and l‑tartaric acid” crystal is, in fact, potassium hydrogen phthalate, (C8H5O4K). Due to no chemical reaction between KHP and l‑tartaric acid in aqueous solution, fractional crystallization of the less soluble KHP occurs. [ABSTRACT FROM AUTHOR]

Recycling Co resource from spent lithium-ion batteries (LIBs) is significant for Co deficiency and environmental protection. A novel approach for in situ recovery of cobalt oxalate (Co(II)-oxalate) from spent LiCoO2 cathodes is proposed. 98.9% Co and 99.6% Li were obtained under the optimized conditions of 1.0 mol/L L-tartaric acid with 5 vol.% H2O2, 10 g/L solid-to-liquid ratio, and 10 min leaching time at 80 °C. Meanwhile, the leaching of Co and Li fits well to Avrami equation model with apparent activation energy of 48.86 and 28.03 kJ/mol, respectively. The first and second stability constants of Co (II) and L-tartaric acid are 1.05 (log K1) and 0.26 (log K2), respectively. 91.8% of high-purity Co(II)-oxalate was regenerated using 5 vol.% H2O2 at 80 °C for 6 h. The whole reaction mechanism was investigated by time-dependent UV–Vis spectroscopy. The proposed in situ Co recovery process proceeds according to the following pathway: Co(III)-tartrate → Co(II)-tartrate → Co(II)-oxalate. In the process, L-tartaric acid mainly acts as a chelating agent and acts as a precursor to form oxalate. Meanwhile, H2O2 mainly acts as a reducing agent and an oxidant. The process may provide an effective and environmentally friendly route for the sustainable recovery of Co(II)-oxalate from spent LIBs. [ABSTRACT FROM AUTHOR]

Binary mixtures of active pharmaceutical ingredients (API) are researched to improve the oral bioavailability of pharmaceutical dosage forms. The purpose of this study was to obtain mixtures of meloxicam and L-tartaric acid because tartaric acid improves intestinal absorption and meloxicam is more soluble in a weakly basic environment. The mixtures in the 0–1 molar fraction range, obtained from solvent-assisted mechanosynthesis, were investigated by differential scanning calorimetry (DSC), Fourier Transform Infrared (FTIR) spectroscopy, Fourier Transform Raman spectroscopy (FT-Raman), X-ray powder diffraction (XRD) and solubility tests. The physicochemical characteristics of the compounds obtained from DSC data reveal, for the first time, the formation of a co-crystal at meloxicam molar fraction of 0.5. FTIR spectroscopy data show the existence of hydrogen bonds between the co-crystal components meloxicam and L-tartaric acid. FT-Raman spectroscopy was used complementary with FT-IR spectroscopy to analyze the pure APIs and their mixtures, to emphasize the appearance/disappearance and the shifts of the position/intensity of vibrational bands, following the formation of hydrogen-bonded structures or van der Waals interactions, and to especially monitor the crystal lattice vibrations below 400 cm−1. The experimental results obtained by X-ray powder diffraction confirmed the formation of the co-crystal by the loss and, respectively, the apparition of peaks from the single components in the co-crystal diffractogram. The solubility tests showed that the co-crystal product has a lower aqueous solubility due to the acidic character of the other component, tartaric acid. However, when the solubility tests were performed in buffer solution of pH 7.4, the solubility of meloxicam from the co-crystal mixture was increased by 57% compared to that of pure meloxicam. In conclusion, the studied API mixtures may be considered potential biomaterials for improved drug release molecular solids.

In our previous work, we adopted the organic acids assisted sol–gel method to prepare ZrO2 aerogels. In preparation process, we found the organic acids with two carboxyl groups and one side group including –OH, –NH2, and –SH were prerequisite to form wet gels. Furthermore, the citric acid with three carboxyl groups and one hydroxyl group was also successfully to form wet gels. Therefore, we speculated that the organic acids required to possess at least two carboxyl groups and one side group to form wet gels. In this work, different organic reagents including acetic acid (AA), oxalic acid (OA), lactic acid (LA), edetic acid (EDTA), butanediol (BD), glycerol (GA), citric acid (CA), L-malic acid (LMA) and L-tartaric acid (LTA) were adopted as gel accelerators to verify our assumption. A series of ZrO2 aerogels were successfully synthesized using ZrOCl2·8H2O as zirconium precursor, and LMA or LTA as the gel initiators by the sol–gel method. It was found that the gelation time of LTA as gelator was shorted than that of LMA in the same condition. When LTA as an gelator, the tetragonal phase can keep until 1000 °C, while for LMA, the tetragonal phase can keep at 800 °C. After supercritical fluid drying (SCFD), ZrO2 aerogel with high surface area of over 339 m2·g−1 and large pore volume of over 0.92 cm3·g−1 can be obtained. Highlights: ZrO2 aerogels have been prepared applying the zirconium source (ZrOCl2·8H2O) and L-malic acid or, L-tartaric acid. The organic acids at least had one side group –OH and two –COOH groups, which were integrant to synthesize ZrO2 aerogel. LMA-6-aerogel has high surface area over 339 m2·g−1 and large pore volume over 0.92 cm3·g−1. [ABSTRACT FROM AUTHOR]

The title hydrated molecular salt, C4H12N+·C4H5O6−·H2O, was prepared by deprotonation of enantiopure l-tartaric acid with racemic sec-butylamine in water. Only one enantiomer was observed crystallographically, resulting from the combination of (S)-sec-butylamine with l-tartaric acid. The sec-butylammonium moiety is disordered over two conformations related by rotation around the CH–CH2 bond; the refined occupancy ratio is 0.68 (1):0.32 (1). In the crystal, molecules are linked through a network of O—H...O and N—H...O hydrogen-bonding interactions, between the ammonium H atoms, the tartrate hydroxy H atoms, and the interstitial water, forming a three-dimensional supramolecular structure.

Abstract: Thermal properties play a vital role particularly for the materials which are used in high power laser irradiation. Photoacoustic technique is very much feasible to findout the thermal transport properties of solid materials. In the present work, nonlinear optical (NLO) single crystal of L‐tartaric acid (LTA) was grown by Sankaranarayanan‐Ramasamy (SR) method for dimensions of 140 mm in length and 11.5 mm in diameter. The grown LTA crystal has been subjected to UV‐Vis‐NIR spectral study to analyze the optical transmittance and absorbance characteristics. The thermal characterization studies were performed using photoacoustic spectrometer (PAS). Thermal characterization involves measurement of thermal parameters such as thermal diffusivity, thermal effusivity, thermal conductivity and specific heat capacity. The experimental results of photoacoustic spectrometer show that the thermal diffusivity of LTA is higher than the reported values of a few other well known NLO materials. [ABSTRACT FROM AUTHOR]

Aspartyl-type peptidases are promising chemotherapeutic targets in protozoan parasites. In the present work, we identified an aspartyl peptidase activity from the soluble extract of Leishmania amazonensis promastigotes, which cleaved the fluorogenic peptide 7-methoxycoumarin-4-acetyl-Gly-Lys-Pro-Ile-Leu-Phe-Phe-Arg-Leu-Lys(DNP)-D-Arg-amide (cathepsin D substrate) under acidic pH conditions at 37°C, showing a KM of 0.58 μM and Vmax of 129.87 fluorescence arbitrary units/s mg protein. The leishmanial aspartyl peptidase activity was blocked by pepstatin A (IC50 = 6.8 μM) and diazo-acetyl-norleucinemetilester (IC50 = 10.2 μM), two classical aspartyl peptidase inhibitors. Subsequently, the effects of 6 asymmetric peptidomimetics, containing L-tartaric acid core, were tested on both aspartyl peptidase and growth of L. amazonensis promastigotes. The peptidomimetics named 88, 154 and 158 promoted a reduction of 50% on the leishmanial aspartyl peptidase activity at concentrations ranging from 40 to 85 μM, whereas the peptidomimetic 157 was by far the most effective, presenting IC50 of 0.04 μM. Furthermore, the peptidomimetics 157 and 154 reduced the parasite proliferation in a dose-dependent manner, displaying IC50 values of 33.7 and 44.5 µM, respectively. Collectively, the peptidomimetic 157 was the most efficient compound able to arrest both aspartyl peptidase activity and leishmanial proliferation, which raises excellent perspectives regarding its use against this human pathogenic protozoan. [ABSTRACT FROM AUTHOR]

A novel organic nonlinear optical (NLO) material, creatininium l -tartrate monohydrate (CTM) was synthesized and it was grown as single crystals with optical quality. 1 H and 13 C NMR spectral studies were performed and molecular structure of synthesized CTM compound was confirmed. Single crystal X-ray diffraction (SXRD) analysis confirmed that CTM was crystallized in orthorhombic system with non-centrosymmetric (NCS), P 2 1 2 1 2 1 , space group. The grown crystal exhibited admirable properties such as second harmonic generation efficiency (SHG) (1.9 times KDP), and high laser damage threshold (LDT) value of 3.7 GW cm −2 . CTM crystal displayed high transparency (∼60%) in the visible and near-IR region with low cut-off wavelength at 249 nm. Photoluminescence study confirmed blue wavelength emission (∼463 nm) of grown crystal. Thermal and mechanical behaviours have been successfully analysed for grown crystals. The dielectric studies were carried out for grown crystal as a function of frequencies at different temperatures. Hirshfeld surface and fingerprint plots provided the percentage of individual interactions contributed by each atom. Moreover, density functional theory (DFT) calculations have been employed to probe the frontier molecular orbitals (FMOs) and first hyperpolarizability (β) analysis of the optimized CTM structure. These results validated CTM as a suitable NLO candidate and were discussed in this work. [ABSTRACT FROM AUTHOR]

Circular dichroism spectra of the optically active ( R)- and ( S)-enantiomers of N, N-(dimethylamino)ethylferrocene (Ugi´s amine) were studied for a free form and for their diastereomeric salts with с l(+)-tartaric acid. [ABSTRACT FROM AUTHOR]

The title hydrated molecular salt, C4H12N+⋅C4H5O6-⋅H2O, was prepared by deprotonation of enantiopure L-tartaric acid with racemic sec-butylamine in water. Only one enantiomer was observed crystallographically, resulting from the combination of (S)-sec-butylamine with L-tartaric acid. The sec-butylammonium moiety is disordered over two conformations related by rotation around the CH-CH2 bond; the refined occupancy ratio is 0.68 (1):0.32 (1). In the crystal, molecules are linked through a network of O--H⋯O and N--H⋯O hydrogen-bonding interactions, between the ammonium H atoms, the tartrate hydroxy H atoms, and the interstitial water, forming a three-dimensional supramolecular structure. [ABSTRACT FROM AUTHOR]

High performance polyamide (PA) thin-film composite (TFC) membranes are in great demand. However, it is still a challenge to further enable PA TFC membranes to overcome the perm-selectivity tradeoff. Here, l -tartaric acid (LTA) and piperazine were first used as the aqueous phase monomers to fabricate LTA integrated PA (LTA/PA) TFC membranes via interfacial polymerization (IP) with trimesoyl chloride. The physicochemical property and separation performance of the PA TFC membranes were regulated via LTA concentrations. The introduction of LTA made the PA layer of the membrane thinner and smoother with enlarged pore size. The LTA/PA TFC membrane prepared with a higher LTA content had a maximal water flux (207.6 LMH/bar, 20 times higher than that of the control membrane), with superior rejections for the dyes (>98.0 %) and low removal rates for the salts (<4.5 %). Of note, the water flux of the membrane prepared with a low LTA content was enhanced to 18.9 LMH/bar without sacrificing the rejection of Na 2 SO 4 (R Na 2 SO 4 > 98.0 %). The membranes with optimal LTA content break the tradeoff towards some dyes or salts, and presented superior performance compared with most other reported polymeric membranes. This work highlights the great potential of constructing natural acid-modulated PA composite membranes in water purification. [Display omitted] • Novel LTA/PA TFC membranes were successfully prepared. • The characteristics of the composite membranes were modulated by adding LTA. • Low LTA content made the membrane have better salt rejection with enhanced flux. • Water flux reached 207.6 LMH/bar while retaining superior dye retention. • The fabricated membrane could be regulated for dyes removal and salt sieving. [ABSTRACT FROM AUTHOR]

Sixteen (16) chiral, amides were synthesized from commercially available L-tartaric acid, having two asymmetric centers and C2 axis of symmetry. The diacid functionality of L-tartaric acid was protected as dimethyl ester and dihydroxy groups as acetonoid. The partial hydrolysis of acetonoid of dimethyl ester gave the corresponding monoester. Monoester upon treatment with different substituted aromatic amines gave desired amides (1-8). Amides (1-8) afforded deprotected compounds (9-16) after reacting with acetyl chloride and methanol. All the compounds were characterized by using spectroscopic techniques such as IR, 1H-NMR, 13C-NMR, and EIMS. The compounds gave reasonable elemental analyses. The structure of compound 6 was unambiguously obtained by X-ray crystallography. Protected (1-8) and deprotected amides (9-16) were tested for their antileishmanial (against Leshmania tropica KWH23 Promastigotes) and antimicrobial activities at different concentrations against different strains of bacteria and fungi. [ABSTRACT FROM AUTHOR]

Chiral protected monoaryl esters ( 2a-2h) were synthesized from monoester of l-tartaric acid, having two asymmetric centers and C2 axis of symmetry. l-tartaric acid was protected and partially hydrolyzed to give the corresponding monoester. Monoester upon treatment with different substituted phenols gave desired monoaryl esters ( 2a-2h). Fries rearrangement of monoaryl esters was then tried under various conditions by using different Lewis acids. All the compounds were purified and characterized by using spectroscopic techniques like IR, H-NMR, C-NMR, HRMS-ESI, and elemental analysis. The structure of compound 2e was obtained by X-ray crystallography. [ABSTRACT FROM AUTHOR]

Readily available L-tartaric acid, which is a bidentate ligand with two chiral centers forming a seven-membered chelate ring, was applied to the chiral ligand for the chiral (NMR) shift reagent of samarium(III) formed in situ. This simple method does not cause serious signal broadening in the high magnetic field. Enantiomeric 13C and 1H NMR signals and enantiotopic 1H NMR signals of α-amino acids were successfully resolved at pH 8.0 and the 1:3 molar ratio of Sm(NO3)3:L-tartaric acid. It is elucidated that the enantiomeric signal resolution is attributed to the anisotropic magnetic environment for the enantiomers induced by the chiral L-tartarato samarium(III) complex rather than differences in stability of the diastereomeric substrate adducts. The present 13C NMR signal resolution was also effective for the practical simultaneous analysis of plural kinds of DL-amino acids. Chirality 27:353-357, 2015.© 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Aims: The aim of the study was to investigate the antihypertensive effect of L-Tartaric acid., Background: L-Tartaric acid (L-TA) is a well-known weak organic acid that naturally occurs in a wide range of fruits, most notably in grapes, tamarind, and citrus., Objective: The present study aimed to assess the effect of acute and subchronic administration of L-TA on blood pressure parameters in normotensive and hypertensive rats as well as its vasorelaxant potency., Methods: In the current study, the antihypertensive activity of L-TA was pharmacologically studied. L-NAME-induced hypertensive and normotensive rats received L-TA (80 and 240 mg/kg) orally over six hours for the acute experiment and seven days for the subchronic treatment. Thereafter, systolic, diastolic, mean, mid arterial blood pressure, and pulse pressure as well as heart rate were evaluated. In the in vitro experiment, the vasorelaxant ability of L-TA was performed in ratisolated thoracic aorta., Results: An important drop in blood pressure was recorded in L-NAME-induced hypertensives treated with L-TA. This molecule also produced a dose-dependent relaxation of the aorta precontracted with norepinephrine (NEP) and KCl. The study demonstrated that the vasorelaxant capacity of L-TA seems to be exerted through the activation of eNOS/NO/cGMP pathways., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Aims: The study investigated the effect of L-tartaric acid on diminazene-indiuced vasorelaxation., Background: Diminazene is known to induce vasorelaxation through the stimulation of angiotensin- converting enzyme (ACE-2)., Objective: This work was designed to study the effect of L-tartaric acid on diminazene-induced vasorelaxation using an ex vivo approach., Materials and Methods: In the current investigation, the inhibitory effect of L-tartaric acid on diminazene-induced relaxation., Results: The results confirmed that L-tartaric acid was able to inhibit in a dose-dependent manner diminazene-induced vasorelaxation., Conclusion: This investigation provides important experimental evidence of the efficacy of Ltartaric acid in inhibiting diminazene-induced vasorelaxation., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

A new heterometallic coordination polymer, namely [Cd3Ca(L-tart)4]n(1 L-tart = L-tartaric acid), has been successfully synthesized and structurally characterized. Single-crystal X-ray analysis reveals that 1 is a complicated three-dimensional (3D) framework, which contains two distinct layers: one containing polyhedrons only based on Cd(II) and the other containing polyhedrons based on Cd(II) and Ca(II). [ABSTRACT FROM PUBLISHER]

Highlights: [•] DFT computations have been performed on l-tartaric acid molecule. [•] FT-IR, FT-Raman and UV–Vis spectra are simulated and compared with those of experimental spectra. [•] ICT interactions and stability of the molecule have been discussed. [•] Quantum chemical molecular orbital properties for LTA were calculated. [•] Open aperture Z-scan technique was used for the third-order non-linear absorption study. [Copyright &y& Elsevier]

A short, versatile, an efficient asymmetric synthesis of substituted aromatic amides is described. L-Tartaric acid conveniently converted into diacetyl-L-tartaric anhydride. Diacetyl-L-tartaric anhydride was then transformed into half ester which was then reacted with substituted anilines to yield respective chiral amides 3-8. These chiral amides were characterized by spectroscopic techniques i.e. 1H-NMR, 13C-NMR, IR and mass spectrometry. Amides 3-8 were tested for their antimicrobial as well as phytotoxic activities. [ABSTRACT FROM AUTHOR]

Highlights: [•] A proton transfer complex is synthesized and characterized by spectral techniques. [•] Bonding modes and structural information are ascertained from crystallographic studies. [•] Single-crystal X-ray studies confirmed the H-bonded network. [•] Thermal analysis (TGA–DTA) was also used to confirm the thermal fragmentation and the stability of the CT complex. [•] Benesi–Hildebrand equation was used to determine K CT, ε CT, and E CT of the CT complex. [ABSTRACT FROM AUTHOR]

Single crystals of L-tartaric acid (LTA), an organic nonlinear optical material, have been grown using a home-built crystal growth setup (the Moovendaran-Kalyanasundar-Natarajan setup). Crystals of LTA were also grown by the slow evaporation solution technique. These single crystals were characterized using single-crystal X-ray diffraction, high-resolution X-ray diffraction, and IR and UV-Vis-NIR spectroscopy. In addition, measurements of Vickers microhardness, laser damage threshold value and second harmonic generation efficiency are reported. Thermal, dielectric and photoluminescence studies were also carried out. [ABSTRACT FROM AUTHOR]

Methyl (2 E,4 S,5 S)-5-hydroxy-6-mesyloxy-2-methyl-4-(pent-3-yloxy)hex-2-enoate was synthesized from l-tartaric acid. Attempted substitution of the mesyloxy group by the reaction with NaN directly led to methyl ( E)-2-[(3 S,4 S)-4-hydroxy-3-(pent-3-yloxy)pyrrolidin-2-ylidene]propanoate. The latter on treatment with CFCOOH and then NaOH gave methyl (2 E)-2-methyl-4-[( S)-oxiran-2-yl]-4-(pent-3-yloxy)but-2-enoate. [ABSTRACT FROM AUTHOR]

An efficient and straightforward method for the preparation of dendritic prodrugs is reported. Based on this new approach, a class of biodegradable dendrimers has been synthesised from L-tartaric acid and one of the nonsteroidal anti-inflammatory drugs, namely, aspirin or ibuprofen. [ABSTRACT FROM AUTHOR]

The solubility of l-tartaric acid was measured in ethanol, propanol, isopropanol, n-butanol, acetone and acetonitrile in the temperature range 281.15 and 324.25 K under atmospheric pressure by a gravimetric method. The solubility of l-tartaric acid in those selected solvents increases with increasing temperature. The apparent molar enthalpies of solution of l-tartaric acid in the selected solvents were estimated from the solubility data. The solubility results were correlated with the van't Hoff equation, the modified Apelblat equation, and the λh equation. Agreement with the experimental data was very good in all cases. The experimental results could be useful for optimizing the purification process of l-tartaric acid in industry. [ABSTRACT FROM AUTHOR]

A new series of main chain H-bonded liquid crystalline polymers were derived from binary mixtures of mesomorphic polymer (I or II) and non-mesomorphic guest molecules like suberic acid, tartaric acid and alkylated tartaric acid. The role of flexible chiral (tartaric acid and alkylated tartaric acid) and achiral (suberic) guest molecules on mesomorphism has been studied. Liquid crystalline properties of polymers and its guest acid complexes were investigated by DSC and POM analysis. The isotropic and melting temperatures of the polymers have been drastically reduced by mixing with flexible guest molecules. [ABSTRACT FROM AUTHOR]

A series of aliphatic copolyesters based on naturally occurring l-tartaric acid amenable to facile post-polymer modification have been synthesized and characterized. The hydroxyl groups of the tartaric acid were protected and copolyesters were synthesized by taking different feed molar ratio of dimethyl 2,3- O-isopropylidene tartarate and dimethyl succinate with 1,6-hexanediol. Then, a series of copolyesters were synthesized by taking equal feed molar ratio of dimethyl 2,3- O-isopropylidene tartrate and dimethyl succinate or dimethyl adipate with different alkane diols. The acetal protecting groups were then selectively hydrolyzed to prepare a new series of copolyesters with pendant hydroxyl groups along the copolymer chain. The number average molecular weights ( M) of the copolymers were found to vary in the range of 3.7-8.4 × 10 g mol. The hydroxy copolyesters show higher glass transition ( T) and melting ( T) temperatures as compared to isopropylidene copolyesters and the T varies from −8.0 to −48.2 °C depending on the feed ratio of the comonomers. The hydrolytic degradation studies of copolyesters revealed that hydroxyl copolyesters degrade faster than isopropylidene copolyesters. [ABSTRACT FROM AUTHOR]

Two novel three-dimensional coordination polymers, formulated as {[M(μ-CHO)(HO)] · 3HO} (M = Mn for 1 and Cd for 2), have been synthesized under hydrothermal reaction condition. Both complexes were characterized by elemental analysis and IR spectroscopy. Their molecular and crystal structures were determined by X-ray crystal structure analysis and their thermal stability by TGA-DTA methods. Compound 1 crystallizes in the monoclinic space group, P2, while compound 2 crystallizes the orthorhombic space group, P222. The structures are self-assembled from bifunctional tartrate and water molecules. Tartrate ligands in 1 and 2 contribute to both covalent and hydrogen bonds. Polymeric chains of 1 and 2 are composed of M(II) ions bridged by tartrate ions in O, O′ fashion. The asymmetric units of coordination polymers contain two metal centers having different coordination environments. [ABSTRACT FROM AUTHOR]

Abstract: Antimony telluride (Sb2Te3) nanoparticles for thermoelectric applications were successfully prepared via a water-based chemical reaction under atmospheric conditions. In this process, we tried to prepare the nanostructured compound by employing both a complexing agent (l-tartaric acid) and a reducing agent (NaBH4) to stabilize the Sb precursor (SbCl3) in water and to favor the reaction with Te. It was observed that various products of Te, Sb2O3, and Sb2Te3 were individually or simultaneously generated depending on the amount of the complexing and reducing agents used. In order to obtain solely a rhombohedral Sb2Te3 compound, the aging time of the reaction needed to be adjusted. [ABSTRACT FROM AUTHOR]

Abstract: A series of aliphatic polyesters based on tartaric acid and its derivatives were synthesized starting from naturally occurring L-tartaric acid. The hydroxyl groups of the tartaric acid derivatives were first protected and the polyesters were synthesized by bulk and solution polycondensation methods. Two classes of polyesters were synthesized and characterized, the first by polycondensation of dimethyl 2,3-O-isopropylidene-l-tartrate with various alkanediols, and the second by reaction of 2,3-O-isopropylidene-l-threitol with various diacid chlorides. Acid catalyzed deprotection of isopropylidene groups gave well-defined polyesters having pendant hydroxyl functional groups regularly distributed along the polymer chain. The number average molecular weights (M n) of the polymers were found to vary in the range of 2.3–15.7 × 103 g mol−1. Differential scanning calorimetry (DSC) analysis showed the glass transition temperatures (T g) of the polyesters varied from −36.1 °C to 17.9 °C on varying the chain length. [Copyright &y& Elsevier]

High speed countercurrent chromatography was applied to the separation of racemic ofloxacin using L-(+)-tartaric acid as chiral selectors. The two-phase system composed of ethyl acetate/methanol/water = 10:1:9 was chosen. The upper phase contained 200 mmol/L of chiral selector. The maximum amount of sample in a one-time injection can be up to 20 mg. The enantiomers separated were identified by HPCE, which confirmed that this method was very useful for the chiral preparative separation. [ABSTRACT FROM AUTHOR]

Abstract: The complex consisting of two piperidine-4-carboxylic acid, l-tartaric acid, water and methanol molecules has been synthesized and characterized by X-ray diffraction, 1H, 13C NMR, 13C CP MAS NMR, FTIR spectra and DFT calculations. The title complex is composed of the following units: piperidinium-4-carboxylate (P4C), piperidinium-4-carboxylic acid (P4CH), semi-tartrate anion (TA), water and methanol; it crystallizes in orthorhombic space group P212121. TA anions form infinite chains through the COOH···OOC hydrogen bond of 2.503(5)Å. The zwitterionic P4C molecules are linked by the N+H···OOC hydrogen bond of 2.780(5)Å into chains. The P4CH cation is a bridge between the TA and P4C chains. P4CH and P4C form a homoconjugated cation through the COOH···OOC hydrogen bonds of 2.559(5)Å. Water interacts with TA and P4CH, while methanol interacts only with water. In the optimized molecule of the (P4C)2H·TA·H2O·HOCH3 complex, the components form a cyclic oligomer through four O–H···O and four N–H···O hydrogen bonds. The 1H and 13C NMR spectra elucidate the structure of the title complex in the aqueous solution. The 13C CP MAS NMR spectrum is consistent with the X-ray results. The FTIR spectrum confirms a very complex structure of the title compound. [Copyright &y& Elsevier]

Abstract: 1,4-Dimethylpiperazine di-betaine (DBPZ) forms a crystalline complex with l-tartaric acid (TA) and two and a half water molecules. The crystals are monoclinic, space group P21. The piperazine has a chair conformation with the methyl groups in the equatorial positions and the axial CH2COO substituents. One of the CH2COO group is protonated and forms with the neighboring DBPZ molecule the COOOOC hydrogen bond of the length 2.476(3)Å, which links them into a chain. The semi-tartrate anions, form a chain through the symmetrical, short COO⋯H⋯OOC hydrogen bond of 2.464(3)Å. The crystals have a layer structure, where hydrogen-bonded sheets of TA and water molecules are separated by the chains of DBPZ; no H-bonds between water and DBPZ are present. In the optimized molecules in the B3LYP/6-31G(d,p) approach, the tartaric acid interacts with the tartrate di-anions through the COOOOC hydrogen bonds of 2.506Å, while the DBPZ has the same conformation as in the crystals. The FTIR spectrum of the solid complex is consistent with the X-ray results. [Copyright &y& Elsevier]