Since the establishment of the coastal industrial complex in Gabes city (Gulf of Gabes, SE Tunisia), hundred million tons of untreated phosphogypsum have been discharged in the open sea causing serious environmental problems. To better understand the dynamic and behavior of phosphate/phosphogypsum contaminants from raw ores to marine environment, a chemical, organic, mineralogical, and morphological characterization of phosphate rock and phosphogypsum was conducted using several sophisticated techniques. The chemical analysis showed that phosphate and phosphogypsum contain high loads of trace elements and that the transfer factors of pollutants varied from 5.83% (U) to 140% (Hg). Estimated annual flows of phosphogypsum contaminants into the marine environment ranged between 0.05 (Re) and 87,249.60 (F) tons. The phosphate rock was found to be formed by carbonate fluorapatite, calcite, dolomite, natural gypsum, quartz, calcite-Mg, apatite, pyrite, fluorite, and sphalerite-Cd and phosphogypsum by synthetic gypsum and sphalerite-Cd. The phosphate was found to be richer in organic compounds compared to phosphogypsum. Based on this work, the Tunisian phosphogypsum has a high mining potential and encourages the development of an economically beneficial and environmentally friendly phosphogypsum-treating industry.

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a b s t r a c tCu(I)-catalyzed 1,3-dipolar cycloaddition between chiral nitrone and terminal alkynes under microwave irradiation afforded a series of enantiopure aziridines with the creation of two contiguous stereogenic centers.

The design of cyclic analogues of 4‐hydroxyisoleucine, a natural remedy used by type‐2 diabetic patients, can provide putative hypoglycemic drugs. To this end, the 1,3‐dipolar cycloaddition of a (–)‐menthone‐derived nitrone to cycloalkenes afforded isoxazolidines in high yields and with high stereoselectivity. The cycloadducts led to α‐amino lactones after a one‐pot cleavage of the N–O, amide, and N–C–N bonds. Subsequent base‐catalyzed hydrolysis provided enantiopure cycloalkylglycine derivatives in good overall yields (>40 %) in three simple synthetic steps from the menthone‐based chiral nitrone. The conformational analysis of these analogues by DFT calculations highlight some interesting features of the volume occupied by the cycloalkyl residues in comparison to that occupied by the natural 4‐hydroxyisoleucine.

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