Reaction #2186199

Reaction equation

2-Amino-5-chloropyridine

4-chloro-3-oxo-butyric acid methyl ester

→

desired product

Yield 31.0%

(6-Chloro-imidazo[1,2-a]pyridin-2-yl)-acetic acid methyl ester

Yield 31.0%

Solvents

toluene

Conditions

Workup

1. 1
   OtherThe resulting brown suspension is evaporated
2. 2
   Temperatureheated 1 h to 90° C. under high vacuum
3. 3
   OtherThe organic phase is then separated
4. 4
   Otherevaporated
5. 5
   Otherto yield a brownish solid
6. 6
   Otherchromatographed (silica gel, ethyl acetate/petroleum ether 4:1)

Procedure

1.28 g (10 mmol) 2-Amino-5-chloropyridine and 1.18 mL (1 eq) 4-chloro-3-oxo-butyric acid methyl ester are heated to 115° C. in 15 mL toluene for 18 h. The resulting brown suspension is evaporated and heated 1 h to 90° C. under high vacuum, then cooled to room temperature and stirred in 100 mL dichloromethane, 10 mL saturated aqueous sodium bicarbonate solution and 40 mL water at 0° C. for one hour. The organic phase is then separated and evaporated to yield a brownish solid that is column chromatographed (silica gel, ethyl acetate/petroleum ether 4:1) to yield 700 mg (31 %) desired product as a beige powder. MS(EI+): 225-227 (M+1).

Source