Synthesis of Cucurbit[6]uril Using 1-Hydroxyethylidene-1,1-Diphosphonic Acid as a “Green Catalyst”

Glycoluril (2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione) and its derivatives have a special place in chemis-try of heterocyclic compounds. The macrocyclic derivatives of glycoluril, namely cucurbit[n]urils have re-cently attracted the greatest interest due to their unique properties. Cucurbit[n]urils are usually synthesized by the condensation reaction of glycoluril with paraformaldehyde using strong mineral acids as a catalyst. In this work, 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) was used for the first time as a catalyst for “Green chemistry” in the synthesis of cucurbit[6]uril in an aqueous medium. The reaction of glycoluril and paraform-aldehyde in a ratio of 1: 2 with two equivalents of 1-hydroxyethylidene-1,1-diphosphonic acid as a catalyst was carried out, in which the hexamer of cucurbituril (n = 6) was obtained in 25 % yield. The clathrate of cu-curbit[6]uril with acetone was obtained by treating the cucurbituril hexamer with acetone. The reaction of glycoluril with paraformaldehyde in the presence of HEDP can be used as a competitive method for the syn-thesis of cucurbit[6]uril. The structures of the obtained compounds were proven by NMR and IR spectrosco-py methods. The phase composition of isolated crystals of cucurbit[6]uril hydrate was analyzed by the pow-der X-ray diffraction (XRD)

Polymerization of Lactic Acid Using Microwave and Conventional Heating

AbstractThe polymerization of lactic acid (LA) has been investigated by two methods: conventional heating and under microwave irradiation. The reactions of polymerization have been carried out in two stages: at the beginning water is removed and oligomer is obtained; then, the catalysts/co-catalysts are added and reactions are carried out. Tin octoate, toluene sulfonic acid, 2-aminopropanoic acid (alanine) have been investigated as polymerization catalysts and the derivatives of 2,4,6,8- tetramethilol -2,4,6,8- tetraazabicyclo[3.3.0]octane -3,7-dion (Tetraol), comprising atoms of Mg, Zn, Al have been synthesized for the first time. The structure of the synthesized catalyst has been investigated using the method of IR, 1H NMR. It has been shown that the process of obtaining polylactic acid (PLA) by microwave irradiation proceeds hundreds of times faster. PLA samples synthesized by this method have the same optical characteristics as the PLA obtained by conventional heating