Reaktion #9003

Reaktionsgleichung

N-Benzylimidazole

formaldehyde

sodium acetate

→

2,5-bis-(hydroxymethyl)-N-benzylimidazole

Ausbeute 24.0%

Lösungsmittel

acetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwere added
2. 2
   Sonstigethen was transferred to a thick-walled glass tube
3. 3
   Sonstigewhich was sealed
4. 4
   Sonstigeplaced in a 140° C.
5. 5
   Sonstigefor 12 hours
6. 6
   TemperaturThe tube was then cooled
7. 7
   Einengenconcentrated
8. 8
   Extraktionextracted twice with a 10:1 isopropanol
9. 9
   TrocknenThe combined organic fractions were then dried over anhydrous sodium sulfate
10. 10
    Einengenconcentrated
11. 11
    SonstigePurification by chromatography on silica gel (7% methanol in dichloromethane)

Vorschrift

Using the procedure of S. Zimmerman et al. (S. C. Zimmerman, K. D. Cramer and A. A. Galan J. Org. Chem. 1989, 54, 1256–1264) N-Benzylimidazole (15 g, 95 mmol) was treated with formaldehyde (60 mL of a 37% aqueous solution), to which glacial acetic acid (8 mL) and sodium acetate (10.5 g) were added. The resulting mixture was stirred until homogeneous, then was transferred to a thick-walled glass tube, which was sealed and placed in a 140° C. oil bath for 12 hours. The tube was then cooled, concentrated, made basic with 10N NaOH, and extracted twice with a 10:1 isopropanol:chloroform mixture. The combined organic fractions were then dried over anhydrous sodium sulfate and concentrated. Purification by chromatography on silica gel (7% methanol in dichloromethane) gave 2,5-bis-(hydroxymethyl)-N-benzylimidazole as a white crystalline solid (4.9 g, 24%). 1H NMR (CDCl3) δ 4.41 (s, 2H), 4.48 (s, 2H), 5.36 (s, 2H), 6.77 (s, 1H), 7.00 (m, 2H), 7.28 (m, 3H).

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