1: 3-hydroxyazetidine-1-carboxylic acid tert-butyl ester With sodium hydride in tetrahydrofuran; mineral oil T=20°C; 1 h; Inert atmosphere; 2: methyl iodide in tetrahydrofuran; mineral oil 2 h; Inert atmosphere;

1: 3-hydroxyazetidine-1-carboxylic acid tert-butyl ester With sodium hydride in tetrahydrofuran T=0 - 20°C; 1.25 h; 2: methyl iodide in tetrahydrofuran T=0°C; 2 h;

1.1: sodium hydrogencarbonate / water; tetrahydrofuran 2.1: sodium hydride / tetrahydrofuran; mineral oil / 0.5 h / 0 °C 2.2: 0 - 20 °C / Sealed tube View Scheme