1.[Total Synthesis of Biologically Active Natural Products toward Elucidation of the Mode of Action].
Yoshida M1. Yakugaku Zasshi. 2015;135(10):1099-108. doi: 10.1248/yakushi.15-00184.
Total synthesis of biologically active cyclodepsipeptide destruxin E using solid- and solution-phase synthesis is described. The solid-phase synthesis of destruxin E was initially investigated for the efficient synthesis of destruxin analogues. Peptide elongation from polymer-supported β-alanine was efficiently performed using DIC/HOBt or PyBroP/DIEA, and subsequent cleavage from the polymer-support under weakly acidic conditions furnished a cyclization precursor in moderate yield. Macrolactonization of the cyclization precursor was smoothly performed using 2-methyl-6-nitrobenzoic anhydride (MNBA)/4-(dimethylamino)pyridine N-oxide (DMAPO) to afford macrolactone in moderate yield. Finally, formation of the epoxide in the side chain via three steps provided destruxin E, and the stereochemistry of the epoxide was determined to be S. Its diastereomer, epi-destruxin E, was also synthesized in the same manner used to synthesize the natural product.
2.Synthesis of novel 68Ga-labeled amino acid derivatives for positron emission tomography of cancer cells.
Shetty D1, Jeong JM, Ju CH, Lee YS, Jeong SY, Choi JY, Yang BY, Lee DS, Chung JK, Lee MC. Nucl Med Biol. 2010 Nov;37(8):893-902. doi: 10.1016/j.nucmedbio.2010.06.003. Epub 2010 Sep 15.
OBJECTIVES: We developed amino acid derivatives of 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (DO2A) and 1,4,7,10-tetraazacyclododecane-1,4,7,-triacetic acid (DO3A) that can be labeled with (68)Ga, and we investigated their basic biological properties.
3.Proteins of the Rpf (resuscitation promoting factor) family are peptidoglycan hydrolases.
Telkov MV1, Demina GR, Voloshin SA, Salina EG, Dudik TV, Stekhanova TN, Mukamolova GV, Kazaryan KA, Goncharenko AV, Young M, Kaprelyants AS. Biochemistry (Mosc). 2006 Apr;71(4):414-22.
The secreted Micrococcus luteus protein, Rpf, is required for successful resuscitation of dormant "non-culturable" M. luteus cells and for growth stimulation in poor media. The biochemical mechanism of Rpf action remained unknown. Theoretical predictions of Rpf domain architecture and organization, together with a recent NMR analysis of the protein structure, indicate that the conserved Rpf domain has a lysozyme-like fold. In the present study, we found that both the secreted native protein and the recombinant protein lyse crude preparations of M. luteus cell walls. They also hydrolyze 4-methylumbelliferyl-beta-D-N,N',N''-triacetylchitotrioside, a synthetic substrate for peptidoglycan muramidases, with optimum activity at pH 6. The Rpf protein also has weak proteolytic activity against N-CBZ-Gly-Gly-Arg-beta-naphthylamide, a substrate for trypsin-like enzymes. Rpf activity towards 4-methylumbelliferyl-beta-D-N,N',N''-triacetylchitotrioside was reduced when the glutamate residue at position 54, invariant for all Rpf family proteins and presumably involved in catalysis, was altered.
4.One-carbon chain extension of esters to alpha-chloroketones: a safer route without diazomethane.
Wang D1, Schwinden MD, Radesca L, Patel B, Kronenthal D, Huang MH, Nugent WA. J Org Chem. 2004 Mar 5;69(5):1629-33.
The reaction of a variety of methyl esters with dimethylsulfoxonium methylide at 0-25 degrees C affords the chain-extended beta-keto dimethylsulfoxonium ylides. Subsequent treatment with hydrogen chloride in THF proceeds with loss of DMSO to afford the corresponding alpha-chloroketones. This sequence has been utilized to convert the methyl esters of CBZ-protected alanine and valine to the anti N-protected alpha-amino epoxides, which are important pharmaceutical intermediates. When the same protocol is applied to BOC-protected phenylalanine methyl ester, epimerization occurs so that the use of a more reactive aryl ester is required. This chemistry provides a practical route to alpha-chloroketones that avoids the use of toxic and explosive diazomethane.
