Sulfuric Acid → 3-{[2,6-Dideoxy-3,4-O-(1-phenylethylidene)hexopyranosyl]oxy}-5,14,19-trihydroxycard-20(22)-enolide

HRID 1283371Notes

Reaction equation

HRID 1283371 reaction equation
[CH3:1][CH:2]1[O:7][C@@H:6]([O:8][C@H:9]2[CH2:25][C@:24]3([OH:26])[C@@:12]([CH:35]=[O:36])([CH:13]4[CH:21]([CH2:22][CH2:23]3)[C@:20]3([OH:27])[C@@:16]([CH3:34])([C@@H:17]([C:28]5[CH2:33][O:32][C:30](=[O:31])[CH:29]=5)[CH2:18][CH2:19]3)[CH2:15][CH2:14]4)[CH2:11][CH2:10]2)[CH2:5][CH:4]2[O:37][C:38]([C:41]3[CH:46]=[CH:45][CH:44]=[CH:43][CH:42]=3)([CH3:40])[O:39][C@H:3]12.[BH4-].[Na+].S(=O)(=O)(O)O>O1CCOCC1>[CH3:1][CH:2]1[O:7][C@@H:6]([O:8][C@@H:9]2[CH2:25][C@:24]3([OH:26])[C@@:12]([CH2:35][OH:36])([CH:13]4[CH:21]([CH2:22][CH2:23]3)[C@:20]3([OH:27])[C@@:16]([CH3:34])([C@@H:17]([C:28]5[CH2:33][O:32][C:30](=[O:31])[CH:29]=5)[CH2:18][CH2:19]3)[CH2:15][CH2:14]4)[CH2:11][CH2:10]2)[CH2:5][CH:4]2[O:37][C:38]([C:41]3[CH:42]=[CH:43][CH:44]=[CH:45][CH:46]=3)([CH3:40])[O:39][C@H:3]12

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 4311764Sodium borohydrideHCID 11967822HCID 11967822, compound2×

Product 1

HCID 372673-{[2,6-Dideoxy-3,4-O-(1-phenylethylidene)hexopyranosyl]oxy}-5,14,19-trihydroxycard-20(22)-enolide

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent2×

Procedure

1.5 g. acetophenone-helveticoside are dissolved in 20 ml. of 80% aqueous dioxane and treated dropwise over a period of 1 hour with a solution of 0.35 g. sodium borohydride in 20 ml. of 75% dioxane. The reaction mixture is stirred for 1 hour, after which no more acetophenone-helveticoside can be detected. The solution is adjusted to pH 7 with dilute sulfuric acid, and the dioxane is removed under reduced pressure in a rotating evaporator. The aqueous phase is repeatedly extracted with chloroform. The combined chloroform extracts are dried over anhydrous sodium sulfate and evaporated. The residue is purified chromatographically over silica gel, using chloroform as solvent. Yield: 750 mg. acetophenone-helveticosol, melting point: 154°-164°C[αD20 ](C = 1, chloroform): ±0°.

Workup

  1. customthe dioxane is removed under reduced pressure in a rotating evaporator
  2. extractionThe aqueous phase is repeatedly extracted with chloroform
  3. dry with materialThe combined chloroform extracts are dried over anhydrous sodium sulfate
  4. customevaporated
  5. customThe residue is purified chromatographically over silica gel
  6. custom±0°

Sources & evidence

ORD record
ord-23e6596cfa184f9fa18b87f09c8943c5
Source dataset
uspto-grants-1976_08
Patent number
US03975373

Reaction notes

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