columbia大学有机化学课件25_01_04 html

1、Chapter 25Carbohydrates25.1Classification of Carbohydratesmonosaccharide disaccharide oligosaccharidepolysaccharideClassification of Carbohydratesis not cleaved to a simpler carbohydrate on hydrolysisglucose, for example, is a monosaccharideMonosaccharideis cleaved to two monosaccharides on hydrolys

2、isthese two monosaccharides may be the same or differentC12H22O11+H2Osucrose(a disaccharide)Disaccharideis cleaved to two monosaccharides on hydrolysisthese two monosaccharides may be the same or differentC12H22O11+H2OC6H12O6+C6H12O6glucose(a monosaccharide)sucrose(a disaccharide)fructose(a monosacc

3、haride)Disaccharideoligosaccharide:gives three or more monosaccharide units on hydrolysispolysaccharide:yields more than 10 monosaccharide unitsHigher SaccharidesNo. of carbonsAldoseKetose45678Aldotetrose Aldopentose Aldohexose AldoheptoseAldooctoseKetotetrose Ketopentose Ketopentose KetoheptoseKeto

4、octoseTable 25.1 Some Classes of Carbohydrates25.2Fischer Projections and D-L NotationFischer ProjectionsFischer ProjectionsFischer Projections of EnantiomersFischer Projections of EnantiomersCHOCHOHOHHOHDLCH2OHCH2OH(+)-Glyceraldehyde()-GlyceraldehydeEnantiomers of Glyceraldehyde25.3The Aldotetroses

5、CHO1HOHHOH4CH2OHstereochemistry assigned on basis of whetherconfiguration of highest-numbered stereogenic center is analogous to D or L-glyceraldehyde23An AldotetroseCHO1HOHHOHD4CH2OHstereochemistry assigned on basis of whetherconfiguration of highest-numbered stereogenic center is analogous to D or

6、 L-glyceraldehyde23An AldotetroseCHO1HOHHOH4CH2OHD-Erythrose23An AldotetroseCHOCHOHOHHOD-Erythrose and L-erythrose are enantiomersHHOHHOHCH2OHD-ErythroseCH2OHL-ErythroseThe Four AldotetrosesCHOCHOD-Erythrose and D-threose are diastereomersHOHHHOHOHHOHCH2OHD-ErythroseCH2OHD-ThreoseThe Four Aldotetros

7、esCHOCHOL-Erythrose and D-threose are diastereomersHOHHHOHOHHOHCH2OHL-ErythroseCH2OHD-ThreoseThe Four AldotetrosesCHOCHOD-Threose and L-threose are enantiomersHOHHHOHHOHOHCH2OHL-ThreoseCH2OHD-ThreoseThe Four AldotetrosesCHOCHOCHOCHOHOHHOHHOHHHOHHOHHOHOHHOHCH2OHD-ErythroseCH2OHL-ErythroseCH2OHD-Threo

8、seCH2OHL-ThreoseThe Four Aldotetroses25.4Aldopentoses and AldohexosesThere are 8 aldopentoses.Four belong to the D-series; the L-series.four belong toTheir names are ribose, arabinose, xylose, and lyxose.The AldopentosesCHOCHOCHOCHOOHOHOHOHHHHHCH2OHD-RiboseCH2OHD-ArabinoseCH2OHD-XyloseCH2OHD-LyxoseT

9、he Four D-AldopentosesCHOCHOCHOCHOOHOHOHOHHOHHHHHHOHHOHHOHCH2OHD-RiboseCH2OHD-ArabinoseCH2OHD-XyloseCH2OHD-LyxoseThe Four D-AldopentosesCHOCHOCHOCHOOH OHOHHOH HH OHOHOHH OHHO HOHH HHH HOHHH OHCH2OHD-RiboseCH2OHD-ArabinoseCH2OHD-XyloseCH2OHD-LyxoseThe Four D-AldopentosesCHOCHOCHOCHOOH OHOHHOH HH OHOHOHH OHHO HOHH HHH HOHHH OHCH2OHD-RiboseCH2OHD-ArabinoseCH2OHD-XyloseCH2OHD-LyxoseThe Four D-AldopentosesThere are 16 aldopentoses.8 belong to the D-s