A practical synthesis of an HIV protease inhibitor intermediate - diastereoselective epoxide formation from chiral α-aminoaldehydes

Application of aziridinium ring opening for preparation of optically active diamine and triamine analogues: highly efficient synthesis and evaluation of DTPA-based MRI contrast enhancement agents

“…The C -benzyl substituted aziridinium ion 4a was prepared starting from primary β-amino alcohols 1a 17 (Scheme 1). Bromination of 1a using NBS/PPh 3 proceeded via formation of phosphonium bromide followed by intramolecular rearrangement to aziridinium ion 2a which further reacted with the bromide counter anion to provide β-bromoamines 3a (86% isolated yield).…”

“…To a solution of ( S )-1a 17 (139 mg, 0.42 mmol) and PPh 3 (165.2 mg, 0.63 mmol) in CHCl 3 (5 mL) at 0 °C was added NBS (112.1 mg, 0.63 mmol) portion wise at 0 °C over 20 min. After the work-up, the residue was purified by silica gel column chromatography eluted with 5% ethyl acetate in hexanes to afford ( R )-3a (142 mg, 85.8%) as a colorless oil.…”

“…(S)-2-Dibenzylamino-3-phenylpropan-1-ol ((S)-1a) 17 To a solution of (S)-phenylalaniol (1.50 g, 10.0 mmol) and K 2 CO 3 (…”

Εφαρμογή Της Βιοκατάλυσης Σε Μη Συμβατικά Συστήματα Στην Αξιοποίηση Των Συστατικών Της Μαστίχας

“…λευκοτριενίων [Bellamy et al 1992, Franck Neumann & Colson 1991, φερεμόνων εντόμων [Millar et al 1990, Rollin & Klaffke 1991, στεροειδών [Joannou fit Reeder 1996, Scherlitz Hoffmann et al 1996] και αντιβιοτικών ενώσεων [Evans et al 1991, Gala & Dibenedetto 1994, Ng et al 1995, Zhang et al 1995. Αλλα παραδείγματα χρήσης των εποξειδίων για τη σύνθεση πολύπλοκων μορίων έχουν δημοσιευτεί από τους Buntel Et Griffin [1992], Chen et al [1993], Corey et al [1994], Frey et al…”

Stereoselective synthesis and application of bi- and trifunctional monoterpene-based compounds

“…Finally catalytic hydrogenation of the azido function resulted in hydroxyethylene isostere CXI (Figure 24)Weyker et al developed a synthesis methodapplying L-phenylalanine (CXIII) as starting materialfor the production of a urea derivative of diaminoalcohol CXVI used for the preparation of HIV protease inhibitors. The key protected epoxide (CXV) was prepared in several steps, subsequent aminolysis in isopropanol resulted in CXVI(Figure 25) 108.…”