Cholesterol → 3alpha-Azidocholest-5-ene

HRID 64251

Reaction equation

HRID 64251 reaction equation
[CH3:1][CH:2]([CH2:4][CH2:5][CH2:6][C@H:7]([C@@H:9]1[C@:27]2([CH3:28])[C@H:12]([C@H:13]3[C@H:24]([CH2:25][CH2:26]2)[C@:22]2([CH3:23])[C:16]([CH2:17][C@H:18]([CH2:20][CH2:21]2)O)=[CH:15][CH2:14]3)[CH2:11][CH2:10]1)[CH3:8])[CH3:3].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.N(C(OC(C)C)=O)=NC(OC(C)C)=O.C1(P([N:76]=[N+:77]=[N-:78])(C2C=CC=CC=2)=O)C=CC=CC=1>O1CCCC1>[N:76]([C@@H:18]1[CH2:20][CH2:21][C@@:22]2([CH3:23])[C:16](=[CH:15][CH2:14][C@@H:13]3[C@@H:24]2[CH2:25][CH2:26][C@@:27]2([CH3:28])[C@H:12]3[CH2:11][CH2:10][C@@H:9]2[C@H:7]([CH3:8])[CH2:6][CH2:5][CH2:4][CH:2]([CH3:3])[CH3:1])[CH2:17]1)=[N+:77]=[N-:78]

Participants

6

Reactant 4

HCID 5997CholesterolHCID 11776TriphenylphosphineHCID 75555Diisopropyl diazene-1,2-dicarboxylateHCID 199401P,P-Diphenylphosphinic azide

Product 1

HCID 133796253alpha-Azidocholest-5-eneYield 67%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

Cholesterol (7.76 mmol, 3.0 g) and triphenylphosphine (7.76 mmol, 2.04 g) were dissolved in 77.6 mL of anhydrous tetrahydrofuran. Diisopropyl azodicarboxylate (7.76 mmol, 1.5 mL) was then added dropwise. After stirring the orange mixture for a few minutes, diphenylphosphoryl azide (7.76 mmol, 1.68 mL) was added dropwise. After 24 hours, the pale yellow reaction mixture was concentrated. Purification by silica gel chromatography (100% hexanes) afforded 3α-azidocholest-5-ene (2.14 g, 67%) as a white solid. mp 110-112° C.; TLC Rf=0.87 (20% ethyl acetate/hexanes); IR (thin film) 2946, 2914, 2845, 2083 cm−1; 1H NMR (300 MHz, CDCl3) δ 5.42-5.40 (m, 1H), 3.89 (t, 1H, J=2.9 Hz), 2.58-2.49 (m, 1H), 2.23-2.16 (m, 1H), 2.16-1.93 (m, 2H), 1.89-1.05 (m, 24H), 1.02 (s, 3H), 0.93 (d, 3H, J=6.5 Hz), 0.88 (d, 6H, J=6.6 Hz), 0.69 (s, 3H).

Workup

  1. concentrationthe pale yellow reaction mixture was concentrated
  2. customPurification by silica gel chromatography (100% hexanes)

Sources & evidence

ORD record
ord-0c703b1171ce4840a83d282d7f1326ee
Source dataset
uspto-grants-2016_09
Patent number
US09447139B2

Linked notes

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