p-Toluenesulfonic acid → Methyl 2,3:4,6-Di-O-benzylidene-alpha-D-mannopryanoside

HRID 2398507

Reaktionsgleichung

Reaktionsgleichung von HRID 2398507
[O:1]([CH3:13])[C@H:2]1[O:10][C@H:9]([CH2:11][OH:12])[C@@H:7]([OH:8])[C@H:5]([OH:6])[C@@H:3]1[OH:4].CO[CH:16](OC)[C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1.[C:25]1([CH3:35])[CH:30]=[CH:29][C:28](S(O)(=O)=O)=[CH:27][CH:26]=1.C(=O)([O-])O.[Na+]>CN(C)C=O.O>[CH3:13][O:1][C@H:2]1[O:10][C@@H:9]2[CH2:11][O:12][CH:16]([C:17]3[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=3)[O:8][C@H:7]2[C@@H:5]2[O:6][CH:35]([C:25]3[CH:30]=[CH:29][CH:28]=[CH:27][CH:26]=3)[O:4][C@H:3]12

Komponenten

7

Edukt 4

HCID 6101p-Toluenesulfonic acidHCID 62375Benzaldehyde dimethyl acetalHCID 101798Methyl alpha-D-mannopyranoside3×HCID 516892Sodium Bicarbonate

Produkt 1

HCID 73631Methyl 2,3:4,6-Di-O-benzylidene-alpha-D-mannopryanoside

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 962WaterLösungsmittelHCID 6228DimethylformamideLösungsmittel

Versuchsvorschrift

A mixture of methyl α-D-mannopyranoside (Compound I, 50 g, 258 mmoles), α,α-dimethoxytoluene (92 g, 600 mmoles), and anhydrous p-toluene-sulfonic acid (1 g) in N,N-dimethylformamide (300 ml), in a 1-liter flask fitted with an air condenser attached to a water aspirator, was stirred magnetically and heated in an oil bath for 3 hours at 65°-75° C. None of the starting Compound I remained after this time (t.l.c., 4:1 ether-petroleum ether). The mixture was poured with vigorous stirring into 1 liter of ice-water containing sodium hydrogen carbonate (30 g). The resultant precipitate was filtered off, resuspended in ice-water, filtered off again, and dried in air and finally in vacuo over phosphorus pentaoxide; yield 90.6 g (95%), m.p. 120°-160° C, [α]D23 -33° (c 1, chloroform).

Aufarbeitung

  1. customin a 1-liter flask fitted with an air condenser
  2. temperatureheated in an oil bath for 3 hours at 65°-75° C
  3. additionThe mixture was poured
  4. filtrationThe resultant precipitate was filtered off
  5. filtrationfiltered off again
  6. dry with materialdried in air and finally in vacuo over phosphorus pentaoxide

Quellen und Nachweise

ORD-Eintrag
ord-a2d4f6e2d6c24c4ea620abc8d54369cb
Quelldatensatz
uspto-grants-1977_05
Patentnummer
US04024333

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