C2-Symmetric Val-Val Dipeptide Isosteres via Diethylaluminium Azide Ring Opening of Epoxyalcohols

Diethylaluminium azide has been used as a highly regio- and stereo-selective reagent for the ring opening of valine-derived, sterically hindered epoxyalcohols. This reagent has enabled extending a previously described synthesis of diaminodiol dipeptide isosteres (P1-Ψ[CH(OH)-CH(OH)]-P1\u27) also to isosteres with branched residues in position P1\u27. The new methodology is compatible with Boe and Cbz proteetion of the starting aminoacid and has been applied to the synthesis of a C2-symmetric diaminodiol Val-Val dipeptide isostere 11, starting from the methyl ester of L-valine, in 25% over-all yield over seven (for Boe proteetion) or six (for Cbz proteetion) passages. A C2-symmetric di-MEM proteeted diaminodiol 17 and a mono-Boc proteeted, desymmetrized derivative 10 have also been obtained by the same approach. Compounds 10, 11 and 17 can be used as core units of C2-symmetric and non-symmetric peptido-mimetic inhibitors of aspartic proteases and as intermediates for the synthesis of cyclic urea inhibitors of HIV-protease

Pregled tehnologija remedijacije perzistentnih otrovnih tvari

This paper gives a review of established and emerging technologies for the treatment of wastes and soils contaminated by Persistent Toxic Substances which include the Persistent Organic Pollutants. The technologies are classified as biological, physico-chemical, and thermal treatments, describing main unit operations and comparing technical, social and environmental limitations, including some potential risks and environmental impacts. Estimated overall costs, cleanup times, reliability, and maintenance levels are also presented in order to assess advantages and limitations of each technology.Ovaj članak donosi pregled postojećih i novonastajućih tehnologija obrade otpada i tla onečišćenog perzistentnim otrovnim tvarima uključujući i perzistentna organska onečišćivala (engl. persistent organic pollutants). Autor dijeli tehnologije obrade na biološke, fizikalno-kemijske i termalne te opisuje rad osnovnih uređaja i uspoređuje tehnička, društvena i ekološka ograničenja, uključujući moguće rizike i učinke na okoliš. Članak također razmatra ukupne procijenjene troškove, vrijeme potrebno za čišćenje te razine odgovornosti i održavanja dajući na uvid prednosti i ograničenja svake tehnologije zasebno

Introduction to ICS-UNIDO Activities and Programmes: Focus on Cleaner Technologies and Sustainable Development

The paper briefly reviews the key issues of the programme which is being developed by the International Centre for Science and High Technology of the United Nations Industrial Development Organization (ICSUNIDO), focused on technologies for sustainable industrial development and more specifically those applicable to chemical and related industries. The first part of the paper describes the concept of sustainability with a short overview of the concept of pollution prevention. The second part is devoted to the overview of ICS-UNIDO programmes, with specific focus on catalysis and sustainable chemistry

Design, synthesis and preliminary evaluation of peptidomimetic inhibitorsof HIV aspartic protease with an epoxyalcohol core

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Theoretical Study on Reactions of Triplet Excited State Thioxanthone with Indole

In the present work, a theoretical study on the deactivation of triplet excited (T1) state thioxanthone (TX) by indole (INH) was performed, based on density functional theory calculations. Three feasible pathways, namely direct electron transfer from INH to T1 state TX, electron transfer followed by proton transfer from INH.+ to TX.−, and H-atom transfer from nitrogen of INH to keto oxygen of T1 state TX, were proposed theoretically to be involved in T1 state TX deactivation by INH

A DFT Study on Deactivation of Triplet Excited State Riboflavin by Polyphenols

The deactivation of triplet excited state riboflavin by polyphenols, e.g. rutin and catechin, was studied on the basis of density functional theory calculations. The results show that the H-atom transfer pathway is more feasible on thermodynamic grounds in comparison with the direct energy transfer or direct electron transfer pathways involved in the triplet excited state riboflavin deactivation by rutin/catechin. The findings are helpful to understand the protective effect of polyphenols against the riboflavin induced photosensitizing damage

C2-Symmetric Val-Val Dipeptide Isosteres via Diethylaluminium Azide Ring Opening of Epoxyalcohols

Diethylaluminium azide has been used as a highly regio- and stereo-selective reagent for the ring opening of valine-derived, sterically hindered epoxyalcohols. This reagent has enabled extending a previously described synthesis of diaminodiol dipeptide isosteres (P1-Ψ[CH(OH)-CH(OH)]-P1\u27) also to isosteres with branched residues in position P1\u27. The new methodology is compatible with Boe and Cbz proteetion of the starting aminoacid and has been applied to the synthesis of a C2-symmetric diaminodiol Val-Val dipeptide isostere 11, starting from the methyl ester of L-valine, in 25% over-all yield over seven (for Boe proteetion) or six (for Cbz proteetion) passages. A C2-symmetric di-MEM proteeted diaminodiol 17 and a mono-Boc proteeted, desymmetrized derivative 10 have also been obtained by the same approach. Compounds 10, 11 and 17 can be used as core units of C2-symmetric and non-symmetric peptido-mimetic inhibitors of aspartic proteases and as intermediates for the synthesis of cyclic urea inhibitors of HIV-protease

The effects of combinatorial chemistry and technologies on drug discovery and biotechnology : A mini review

The review will focus on the aspects of combinatorial chemistry and technologies that are more relevant in the modern pharmaceutical process. An historical, critical introduction is followed by three chapters, dealing with the use of combinatorial chemistry/high throughput synthesis in medicinal chemistry; the rational design of combinatorial libraries using computer-assisted combinatorial drug design; and the use of combinatorial technologies in biotechnology. The impact of "combinatorial thinking" in drug discovery in general, and in the examples reported in details, is critically discussed. Finally, an expert opinion on current and future trends in combinatorial chemistry and combinatorial technologies is provided