160208-45-7Relevant academic research and scientific papers
Assignment of the absolute configuration of natural lentiginosine by synthesis and enzymatic assays of optically pure (+) and (-)-enantiomers
Brandi,Cicchi,Cordero,Frignoli,Goti,Picasso,Vogel
, p. 6806 - 6812 (2007/10/03)
The structure and absolute configuration of natural lentiginosine isolated from plant sources was determined to be (1S,2S,8aS)-1,2-dihydroxyindolizidine ((+)-4) on the basis of the synthesis of both enantiomers (+)-4 and (-)-4 and their inhibition of amyloglucosidases. Alkaloid (+)-4 was derived from (L)-(+)-tartaric acid via a highly stereo- and regioselective 1,3-dipolar cycloaddition of (3S,4S)-3,4-bis[(tert-butyldiphenylsilyl)oxy]-1-pyrroline N-oxide to methylenecyclopropane, followed by thermal rearrangement of the adduct into (1S,2S,8aS)-1,2-[(tert-butyldiphenylsilyl)oxy]octahydroindolizin-7-one . The enantiomer (-)-4 was derived in the same way from (D)-(-)-tartaric acid. Both (+)-4 and (-)-4 displayed inhibition specificity for amyloglucosidases, being inactive toward 17 other glycosidases. With amyloglucosidase from Aspergillus niger, synthetic (+)-4 displayed inhibition (K(i) = 2 μM) 5 times stronger than that reported for natural lentiginosine, 35 times that measured for (-)-4, and twice that of castanospermine. Alkaloid (+)-4 is thus the most potent and specific competitive inhibitor of amyloglucosidases among azasugars and their analogues.
Synthesis of Lentiginosine by stereoselective chiral nitrone cycloaddition and thermal rearrangement of strained spiroisoxazolidine
Cordero, Franca M.,Cicchi, Stefano,Goti, Andrea,Brandi, Alberto
, p. 949 - 952 (2007/10/02)
The total synthesis of Lentiginosine (3) is reported. The strategy is based on the 1,3-dipolar cycloaddition of a TBDPS protected 3,4-dihydroxypyrroline N-oxide to methylenecyclopropane followed by the thermal rearrangement of the resulting spirocycloprop
