Formamide → Ethyl 4-methyloxazole-5-carboxylate

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This compound was prepared according to the procedure described in French Pat. No. 1,543,853. A mixture of 50.0 g (0.337 moles) of ethyl chloroacetoacetate and 42.0 g (0.933 moles) of formamide was stirred at 120°-135° for 18 hr. Thereafter, the mixture was cooled using an ice bath to 10° C. 300 ml of 1 N K2CO3 was added dropwise with gas evolution noted. After complete addition of K2CO3 solution, the reaction mixture was stirred with 200 ml of benzene/ether (2:1) and saturated with NaCl. The insoluble material was filtered and the benzene/ether layer was separated and washed with water, dried (MgSO4) and concentrated under reduced pressure. The brown residue was distilled on a Kugelrohr to give 14.8 g of white solid, mp 31°-33° C.; yield 31%; nmr (CDCl3) 8.0 (s,1H,C2H), 44 (q, J=7 Hz, 2H,CH2), 2.5 (s,3H,CH3), 1.4 (t,3H,CH3).

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