1.Glycine-d-tartaric acid (1/1).
Mohandas T1, Inbaseelan CR, Saravanan S, Sakthivel P. Acta Crystallogr Sect E Struct Rep Online. 2013 Feb 1;69(Pt 2):o236. doi: 10.1107/S1600536813000822. Epub 2013 Jan 16.
In the title co-crystal, C(2)H(5)NO(2)·C(4)H(6)O(6), the gylcine mol-ecule is present in the zwitterion form. In the tartaric acid mol-ecule there is a short intra-molecular O-H⋯O contact. In the crystal, the tartaric acid mol-ecules are linked via pairs of O-H⋯O hydrogen bonds, forming inversion dimers. These dimers are linked via a number of O-H⋯O and N-H⋯O hydrogen bonds involving the two components, forming a three-dimensional network.
2.Enantiospecific formal total synthesis of iriomoteolide 3a.
Kumar SM1, Prasad KR. Chem Asian J. 2014 Dec;9(12):3431-9. doi: 10.1002/asia.201402593. Epub 2014 Sep 18.
A formal total synthesis of the marine macrolide iriomoteolide 3a is described. Salient features of the synthesis include the elaboration of a β-keto phosphonate derived from D-(-)-tartaric acid and the extension of a chiral butyrolactone derived from L-glutamic acid. Ring-closing metathesis is employed to construct the macrolactone core of the natural product.
3.Ultraviolet radiation induces stress in etiolated Landoltia punctata, as evidenced by the presence of alanine, a universal stress signal: a ¹⁵N NMR study.
Monselise EB1, Levkovitz A, Kost D. Plant Biol (Stuttg). 2015 Jan;17 Suppl 1:101-7. doi: 10.1111/plb.12198. Epub 2014 May 29.
Analysis with (15) N NMR revealed that alanine, a universal cellular stress signal, accumulates in etiolated duckweed plants exposed to 15-min pulsed UV light, but not in the absence of UV irradiation. The addition of 10 mm vitamin C, a radical scavenger, reduced alanine levels to zero, indicating the involvement of free radicals. Free D-alanine was detected in (15) N NMR analysis of the chiral amino acid content, using D-tartaric acid as solvent. The accumulation of D-alanine under stress conditions presents a new perspective on the biochemical processes taking place in prokaryote and eukaryote cells.
4.Enantioselective Extraction System Containing Binary Chiral Selectors and Chromatographic Enantioseparation Method for Determination of the Absolute Configuration of Enantiomers of Cyclopentolate.
Szwed K1, Górecki M, Frelek J, Asztemborska M. Chromatographia. 2013;76:1603-1611. Epub 2013 Aug 23.
The distribution coefficients and enantioseparation of cyclopentolate were studied in an extraction system containing d-tartaric acid ditertbutyl ester in organic phase and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) in aqueous phase. Various parameters involved in the enantioseparation such as the type and the concentration of chiral selectors, pH value and a wide range of organic solvents were investigated. The maximum enantioselectivity (α = 2.13) and optimum distribution coefficients (K R = 0.85, K S = 0.40) were obtained under the following conditions: 0.10 mol/L HP-β-CD in aqueous phase and 0.20 mol/L d-tartaric acid ditertbutyl ester in decanol as organic phase. Cyclopentolate is present as a racemic mixture to the aqueous phase. The potentially different biological activities of cyclopentolate enantiomers have not been examined yet. Two chiral liquid chromatography methods have been developed for the direct separation of the enantiomers of cyclopentolate.
