Vibrational circular dichroism (VCD) was first applied to the stereochemical analysis of sphingosine. VCD patterns derived from the C═C stretch as well as other mid-infrared (IR) regions were practical markers to discriminate all the stereoisomers of intact sphingosine. Glutaraldehyde was found as an excellent derivatizing reagent for sphingosine which improves its solubility in VCD-friendly nonpolar solvents such as chloroform and enhances the VCD intensities by forming a rigid cyclized structure.

Sphingoid bases, which have a 2-amino-1,3-diol common functional group, are the structural backbone units of all sphingolipids. Recently, much attention has been focused on sphingoid bases because of their potentially beneficial bioactivities toward various cancer cells as well as their dietary interest. However, low abundance and the handling complexity caused by their amphiphilic character led to very limited research on them. Glutaraldehyde has two aldehyde groups, and it reacts rapidly with the 2-amino-1,3-diol functional group of sphingosine to give a tricyclic product. Immobilization of glutaraldehyde on a resin was successfully performed by organic synthesis, starting from trans-p-coumaric acid via eight steps. This approach suppresses the self-polymerization of glutaraldehyde, and addition of water to the developed resin causes the formation of cyclic double hemiacetal function, which avoids oxidation like a reducing sugar in nature and makes it stable even for up to 1 year incubation. The resin was applied to the solid-phase extracting experiment of free sphingosine from human serum at a concentration of 280 nM. Another extraction study of edible golden oyster mushrooms showed that the sphingoid base was selectively captured from complex natural extracts. These results demonstrate that the developed glutaraldehyde resin method is a highly selective method, and hence, the combination of it with the o-phthaldialdehyde HPLC method was confirmed as an efficient and sensitive method for analysis of sphingoid bases in biological samples.

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Background: Pyrimidinones and its derivatives are present in many anti-cancer agents, it has been reported that these substances were proven to have significant activities against different types of human cancers. The incorporation of [1,2,3]-triazole, a nitrogen rich unit not only increases the efficacy but also increases lipophilicity of the drug molecule. As our research to synthesize newer molecules of effective cytotoxicity, we focused on pyrimidinone and [1,2,3]-triazoles systems, as important scaffolds with the expectation of potential cytotoxic properties. Methods: Novel series of [1,2,3]-triazole carboxamides (5a-j) were synthesized starting from 3-(2-chloroethyl)-2-methyl-6,7,8,9-tetrahydropyrido[1,2-a]pyrimidin-4-one. Structure of all the synthesized compounds were elucidated based on IR, 1H-NMR, 13C-NMR and LC-MS data. Compounds were focused for their in vitro cytotoxicity against A375 melanoma cancer cell lines, MDA-MB-231 breast cancer cell lines and HEK 293-Human embryonic kidney cell lines using colorimertic MTT assay. The potent compound was evaluated for DNA binding studies. Results: Most of the Pyrimidinone conjugated [1,2,3]-triazole carboxamides found to be selective towards melanoma cancer cell lines than breast cancer cell lines. Compounds 5d, 5i and 5b were effective against A375 cancer cell lines and are found to be non-toxic against HEK 293-Human embryonic kidney cell lines. The potent compound 5d showed good intrinsic binding constant (Kb) value 3.12 x 103 M-1 in UV based DNA titration. Conclusion: Newly synthesized pyrimidinone conjugated 1,2,3-triazole carboxamide derivatives showed the significant cytotoxicity and the potent compound showed good intrinsic binding constant in UV based DNA titration.

One-Pot Synthesis of Benzimidazoles from gem-Dibromomethylarenes Using o-Diaminoarenes. -(SIDDAPPA, C.; KAMBAPPA, V.; SIDDEGOWDA, A. K. C.; RANGAPPA*, K. S.; Tetrahedron Lett. 51 (2010) 50, 6493-6497, http://dx.