Reaktion #5218

Reaktionsgleichung

trifluoroacetic acid

6-chloro-4-iodo-2-methoxy-3-pyridinecarboxaldehyde

triethylsilane

methanol

NaHCO3

→

2-chloro-4-iodo-6-methoxy-5-(methoxymethyl)pyridine

Lösungsmittel

ether

Reaktionsbedingungen

Aufarbeitung

1. 1
   ExtraktionThe aqueous layer was extracted with ether (10 mL)
2. 2
   Waschenthe combined ether layers were washed with water (10 mL) and brine (10 mL)
3. 3
   Trocknendried (Na2SO4)
4. 4
   EinengenConcentration
5. 5
   Sonstigegave the crude product which
6. 6
   Sonstigewas purified by radial PLC (silica gel, 5% ethyl acetate/hexanes)

Vorschrift

To a mixture of 6-chloro-4-iodo-2-methoxy-3-pyridinecarboxaldehyde (1.07 g, 3.60 mmol), triethylsilane (0.86 mL, 5.40 mmol) and methanol (0.43 mL, 10.6 mmol) at 0° C. was added trifluoroacetic acid (2.2 mL, 28.6 mmol), and the resulting solution was stirred at 25° C. for 14 h. After dilution with ether (30 mL), saturated NaHCO3 was added until the aqueous phase was rendered basic. The aqueous layer was extracted with ether (10 mL), and the combined ether layers were washed with water (10 mL) and brine (10 mL), and dried (Na2SO4). Concentration gave the crude product which was purified by radial PLC (silica gel, 5% ethyl acetate/hexanes) to afford 2-chloro-4-iodo-6-methoxy-5-(methoxymethyl)pyridine as a white solid (1.05 g., 93%): mp 69°-72° C. Recrystallization from hexanes provided an analytical sample: mp 74°-75° C. 1H NMR (300 MHz, CDCl3) δ 7.40 (S, 1H), 4.53 (s, 2H), 3.96 (s, 3H), 3.42 (s, 3H); IR (nujol) 1550, 1300, 1115, 1090, 1020, 940, 905, 830, 720 cm-1.

Quelle