Acetic Anhydride → HCID 54228403, compound

Participants

Reaction Steps

A flask equipped with a mechanical stirrer, reflux condenser, dropping funnel, and drying tube was charged with 38.5 g (0.33 mol) of N-acetylglycine (2), 134 g (1.3 mol) of acetic anhydride, 54 g (0.166 mol) of lead acetate, and 450 ml of tetrahydrofuran (THF). The mixture was heated with stirring at reflux temperature for 1 hr. A solution consisting of 37 g (0.5 mol) of methoxyacetaldehyde (1) and 220 ml of THF was then added dropwise over a 21/2 hr period. The resultant mixture was heated with stirring at reflux temperature for an additional 4 hrs. The reaction was allowed to cool, diluted with 1 l. of ether, and filtered through a pad of Celite®. The filtrate was concentrated in vacuo and the dark brown fluid residue was distilled under reduced pressure. The fraction boiling at 60°-83°/0.5 mm consisted mainly of 4-(2-methoxyethylidene)-2-methyl-5-oxazolone (3): NMR (CDCl3) δ 6.5 (m, 1H, --CH2CH=), 4.35 (m, 2H, --CH2CH--), 3.3 (s, 3H, CH3O--), 2.2 ##STR5##

Provenance & Evidence