The study of oxygen heterocyclic compounds (coumarins, psoralens, polymethoxylated flavones) in natural matrices such as citrus oils is not easy due to the difficulty of obtaining standards at the required level of purity and the diversity of structures present in each kind of sample. In this work, standards were either isolated by preparative LC methods from citrus oils or synthesized, then characterized by their physicochemical parameters and spectroscopic techniques, and further used for qualitative and quantitative calculations in citrus essential oils and products made with them (Earl Grey tea, liquors, juices). An HPLC method using an innovative partially porous particle HPLC column enabled baseline separation of all analytes. The method developed was validated in terms of detection limit, quantitation limit, linearity, and precision as repeatability and intralaboratory reproducibility.

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a b s t r a c tTruncated phosphonated C-1 0 -branched N,O-nucleosides have been synthesized in good yields by 1,3-dipolar cycloaddition methodology, starting from N-methyl-C-(diethoxyphosphoryl)nitrone 7. Preliminary biological assays show that b-anomers are able to inhibit HIV in vitro infection at concentrations in the micromolar range. Higher SI values with respect to AZT indicated that the compounds were endowed with low cytotoxicity.

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A novel series of C-nucleosides, featuring the presence of a 1,2,3-triazole ring linked to an isoxazolidine system, has been designed as mimetics of the pyrimidine nucleobases. An antiproliferative effect was observed for compounds 17a and 17b: the growth inhibitory effect reaches the 50% in HepG2 and HT-29 cells and increases up to 56% in the SH-SY5Y cell line after 72 h of incubation at a 100 µM concentration.

Affairs of the HAART! The synthesis of HEPT‐derived, truncated reverse isoxazolidinyl nucleosides (shown) is reported. These compounds represent the first examples of isoxazolidines bearing a pyrimidine scaffold at the C‐3 position using a glycoside‐type linkage. Biological evaluation showed that some of the derivatives act as non‐nucleoside inhibitors of HIV‐1 reverse transcriptase, with an efficacy comparable to that of Nevirapine but with reduced toxicity.