A practical method for the preparation of α′-chloroketones of N-carbamate protected-α-aminoacids

Probing the potential of platinum(II) complexes for the inhibition of thiol-dependent enzymatic activity

“…Addition of morpholine acetyl chloride to leucine methyl ester gave compound 6, which was efficiently converted to the chloroketone 7 by the Kowalski method, utilizing excess of LDA and CH 2 ICl [12]. We found this method preferable to the classical method, involving conversion of an Nacyl-a-amino acid to an a-diazoketone and subsequent acidolysis with HX [13], as the use of diazomethane is avoided.…”

Synthesis of13C6-labeled Reyataz? (BMS-232632)

“…The route used to synthesize 13 C 6 -labeled Reyataz TM ([ring- 3,4 The key to the synthesis was the use of [ring-13 C 6 ]-l-phenylalanine as the starting material. This 13 C 6 -labeled compound is commercially available with high enantiomeric and isotopic purity.…”

“…3 The solution was cooled to À788C and stirred under argon. An LDA solution (freshly prepared from n-butyllithium (30.6 ml, 76.59 mmol, 2.5 M solution in hexanes) and diisopropylamine (11.8 ml, 8.53 g, 84.25 mmol)) at À788C was added dropwise to the reaction flask over 40 min via a cannula.…”

“…3 The solution was stirred at room temperature under argon for 1 h. At that time the reaction mixture was concentrated and the concentrate was diluted with water (50 ml). The aqueous solution was extracted with EtOAc (3 Â 25 ml).…”

Diastereoselective synthesis of vicinal amino alcohols

“…The reductions typically proceeded in 4 : 1 dr but were easily purified by crystallization to full chemical and optical purity. 41 Similar to α-chloromethylketones, α-bromomethylketones can be reduced in a highly diastereoselective manner (Scheme 30) simply with sodium borohydride. Several reducing agents and conditions were screened and it should be noted that no conditions were able to provide the syn-product in better than 1 : 2 ratio.…”