1: 7-amino-3-hydroxymethyl-8-oxo-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid With sodium hydroxide in methanol; water T=38 - 50°C; 1 h; 2: 2-methoxyimino-2-(fur-2-yl)acetyl chloride in methanol; DMF (N,N-dimethyl-formamide); dichloromethane; isobutyramide; water T=0 - 2°C;