Acetic Anhydride → 1alpha,25-Dihydroxycholesterol triacetate

HRID 651951Notes

Reaction equation

HRID 651951 reaction equation
[OH:1][C@@H:2]1[C@@:27]2([CH3:28])[C:6](=[CH:7][CH2:8][C@@H:9]3[C@@H:26]2[CH2:25][CH2:24][C@@:23]2([CH3:29])[C@H:10]3[CH2:11][CH2:12][C@@H:13]2[C@H:14]([CH3:22])[CH2:15][CH2:16][CH2:17][C:18]([OH:21])([CH3:20])[CH3:19])[CH2:5][C@@H:4]([OH:30])[CH2:3]1.C([O:34][C:35](=[O:37])[CH3:36])(=O)C.C1C=CC=CC=1.CCCCCC>N1C=CC=CC=1>[OH:1][C@@H:2]1[C@@:27]2([CH3:28])[C:6](=[CH:7][CH2:8][C@@H:9]3[C@@H:26]2[CH2:25][CH2:24][C@@:23]2([CH3:29])[C@H:10]3[CH2:11][CH2:12][C@@H:13]2[C@H:14]([CH3:22])[CH2:15][CH2:16][CH2:17][C:18]([OH:21])([CH3:20])[CH3:19])[CH2:5][C@@H:4]([OH:30])[CH2:3]1.[CH3:27][C:2]([CH2:3][C:4]([CH2:36][C:35]([OH:34])=[O:37])=[O:30])=[O:1]

Participants

5

Reactant 3

HCID 7918Acetic AnhydrideHCID 110624Benzene hexaneHCID 1911241 Alpha,25-dihydroxycholesterol

Product 1

HCID 1317151651alpha,25-Dihydroxycholesterol triacetate

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Procedure

The triol from (b) above (0.5 g) in pyridine (0.5 ml) and acetic anhydride (8 ml) was heated at reflux for 1.5 hours. The solution was cooled, poured into ice-water and stirred to decompose the anhydride. Work up by extraction with ethyl acetate as usual gave a brown oil which was chromatographed on alumina (act. III, 25 g). Elution with hexane-benzene (7:3) gave a trace of non polar material. Benzene-hexane (1:1) yielded the title compound (0.58 g) as a very soluble colourless oil which resisted all attempts at crystallization. This material was homogeneous on t.l.c. on silica gel, alumina and silica gel-silver nitrate. νmax. (film) 1730 cm-1 (CDCl3) 5.50 (1 proton, narrow multiplet, H6), δ5.2-4.6 (2 protons, one broad and one narrow multiplet, H1 and H3 with H1 as a narrow multiplet at δ5.03), 2.00, 1.98, 1.91 (singlets, acetates), 1.40, 1.05, 0.67 (singlets, C26-27, C19, C18 methyls respectively.

Workup

  1. temperatureat reflux for 1.5 hours
  2. temperatureThe solution was cooled
  3. extractionWork up by extraction with ethyl acetate
  4. customas usual gave a brown oil which
  5. customwas chromatographed on alumina (act. III, 25 g)
  6. washElution with hexane-benzene (7:3)
  7. customgave a trace of non polar material

Sources & evidence

ORD record
ord-8410bae9d56b43f899464a123c685317
Source dataset
uspto-grants-1987_06
Patent number
US04670190

Reaction notes

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