| abstract |
Prodn. of gamma-butyrolactone derivs. of formula (I) comprises reacting alkylene oxide (II) and acylacetate ester (III) in the presence of 0.001-0.1 mole per mole (II) of a catalyst (A) at 20-200 deg.C and 1-50 bars. (A) is an alkali, ammonium (pref. quat. ammonium) or phosphonium halide, alkali phosphate or alkali carbonate. (R1 = H or 1-4C alkyl (opt. substd. by lower alkoxy or acyloxy); R2 = 1-2C alkyl (opt. substd. by a functional gp. such as lower alkoxy, acyloxy, amido, OH, aryl or halo) or aryl; R3 and R4 = 1-6C alkyl or aryl, and R4 can also be H; R5 = H or R2). A mixt. of solvent, catalyst (esp. 0.003-0.5 mole per mole (II)) and (III) is pref. treated with (II) over 1-10 hr. at reaction temp. To improve yields, a small amt. (0.1-0.5 mole per mole (III)) of strong base is added after reaction, and then this neutralised with inorganic acid. |