p-Toluenesulfonic acid → HCID 101025554, compound

HRID 894475Notes

Reaction equation

HRID 894475 reaction equation
[CH3:1][C@@H:2]([CH:22]([OH:24])[CH3:23])[CH:3]1[O:5][CH:4]1[CH2:6][C@H:7]1[C@H:12]([OH:13])[C@H:11]([OH:14])[C@H:10]([CH2:15]/[C:16](/[CH3:21])=[CH:17]/[C:18]([OH:20])=[O:19])[O:9][CH2:8]1.C1(C)C=CC(S(O)(=O)=O)=CC=1.C(=O)(O)[O-].[K+].[Se-]C#N.[K+].C(O)(CC)(C)C.O>COC(OC)(C)C.C(OCC)(=O)C>[CH3:1][C@@H:2]([C@@H:22]([OH:24])[CH3:23])[C:3]1[O:5][C:4]=1[CH2:6][C@@H:7]1[C@@H:12]([OH:13])[C@@H:11]([OH:14])[C@H:10]([CH2:15]/[C:16](/[CH3:21])=[CH:17]/[C:18]([OH:20])=[O:19])[O:9][CH2:8]1

Participants

8

Reactant 5

HCID 6101p-Toluenesulfonic acidHCID 76960Potassium selenocyanateHCID 516893Potassium BicarbonateHCID 6455298HCID 6455298, compoundHCID 129645095HCID 129645095, compound

Product 1

HCID 101025554HCID 101025554, compound

Reagents, catalysts & solvents 2

HCID 64952,2-DimethoxypropaneSolventHCID 8857Ethyl AcetateSolvent2×

Procedure

Monic acid A (3.44 g) was dissolved in 2,2-dimethoxypropane (30 ml) and ethyl acetate (30 ml) with a few crystals of p-toluene sulphonic acid. After one hour the solution was diluted with ethyl acetate and washed with brine then dried (MgSO4). The solvent was removed in vacuo and the acetonide dissolved in water-methanol (1:1, 40 ml) then treated with potassium bicarbonate (1.0 g, 1 eq). The solution was evaporated to dryness and potassium selenocyanate (4.32 g, 3 eq), tert-amyl alcohol-water (9:1, 150 ml) added and reaction refluxed for 42 hours. After filtering, the reaction mixture was diluted with ethyl acetate and extracted with water (4×25 ml). The combined aqueous phases were acidified (pH2, 5 M-HCl) and extracted with ethyl acetate (4×25 ml) and the combined extracts dried (MgSO4). The solvent was removed in vacuo to give 6,7-O-ispropylidene monic acid C, νmax (CHCl3) 1695, 1640, 1380, 1370, 1220 and 1055 cm-1 ; δ H (CDCl3) 0.98 (3H, d, CH3 -17), 1.13 (3H, d, CH3 -14), 1.33 and 1.48 (6H, d, acetonide CH3 's), 2.17 (3H, s, CH3 -15), 5.45 (2H, m, H-10, H-11), 5.75 (1H, s, H-2), 4.35 (2H, broad, CO2H, OH); δC (CDCl3) 170.5 (C1), 158.3 (C3), 134.9, 128.8 (C10, C11), 117.5 (C2), ##STR7## 76.5 (C5), 75.7 (C7), 74.1 (C6), 71.1 (C13), 66.5 (C16), 44.3 (C12), 36.8 (C8), 34.1 (C9), 28.3, 26.3 (C(CH3)2), 20.1 (C14), 19.3 (C15), 16.3 (C17); m/e (relative intensity) 353 (9) (Found: 353.1995. M+ --CH3 requires 353.2026) 350 (4) (M+ --H2O). The acetonide was dissolved in 80% acetic acid (100 ml) then left overnight. The solution was evaporated to dryness and chromatographed on silica (50 g) eluting with 0-10% methanol-chloroform. The fractions containing pure product (tlc) were combined and evaporated to give monic acid C m.p. 101°-102° C. (2.57 g, 72%) (Found: C, 61.8; H, 8.4. C17H28O6 requires C, 62.2; H, 8.6%).

Workup

  1. washwashed with brine
  2. dry with materialthen dried (MgSO4)
  3. customThe solvent was removed in vacuo
  4. dissolutionthe acetonide dissolved in water-methanol (1:1, 40 ml)
  5. additionadded
  6. customreaction
  7. temperaturerefluxed for 42 hours
  8. filtrationAfter filtering
  9. additionthe reaction mixture was diluted with ethyl acetate
  10. extractionextracted with water (4×25 ml)
  11. extractionextracted with ethyl acetate (4×25 ml)
  12. dry with materialthe combined extracts dried (MgSO4)
  13. customThe solvent was removed in vacuo

Sources & evidence

ORD record
ord-453b8facfcf141a882438b239767b115
Source dataset
uspto-grants-1981_08
Patent number
US04284570

Reaction notes

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