RESUMEN
Following the work already carried out in our laboratory on eucalyptol, a new green solvent derived from biomass, we are now looking at sabinene as another new green solvent. Sabinene is also derived from biomass, has no known toxicity and can be recycled by distillation. We have shown that it can be used as it is or distilled to synthesize thiazolo[5,4-b]pyridine heterocycles by thermal activation or microwave irradiation. This new solvent was compared with various conventional and green solvents. The conditions were optimised to enable us to carry out the syntheses in satisfactory yields, and we were able to show that sabinene, a natural bicyclic monoterpene, could be used effectively as a solvent.
RESUMEN
Pyrazine-fused 1,2,6,6a-tetrazapentalenes (PyTeAP) are zwitterionic tricyclic compounds exhibiting an original pattern with four consecutive nitrogen atoms. They were obtained by a challenging cyclization through the formation of a N-N bond under thermolytic conditions. Ten derivatives were synthesized, and the original scaffold of PyTeAP was confirmed by single-crystal X-ray diffraction analysis of one derivative. Examination of their photophysical properties in solution revealed blue fluorescence with λem = 416-426 nm. Theoretical investigations of the aromaticity in these compounds through magnetic criteria evidenced the presence of a dominant 14-electron circuit at the periphery.
RESUMEN
Extraction, isolation and characterization of Andrographis paniculata (A.p.) products were developed. Three natural diterpenes compounds were obtained and one was used for chemical modifications. Evaluation of their inhibition of TNFα induced NFκB transcriptional activity. A rapid analytical method for the determination and quantitation of three diterpenoid lactones (andrographolide 1, didehydroandrographolide 2, neoandrographiside 3) found in A. paniculata extracts was investigated. After some optimizations on column type and injection solvent, the separation was achieved in 9 min on a monolithic Chromolith Performance RP18e column (100 mm × 4.6 mm ID, 2 µm), with a gradient solvent system of water and methanol, UV detection at 220 nm and ELSD detection. The method was proved to be suitable for the quantitation of these three diterpenes in four different commercial Andrographis dietary supplements. The anti-inflammatory activities of a mixture of known composition have been evaluated showing differences in activity depending on the relative ratio of various diterpenes and also a possible synergic activity for some of them.