1: 4-methyl-3-oxopentanoic acid methyl ester; 4-fluorobenzaldehyde With acetic acid; 3-aminopropionic acid in cyclohexane T=20°C; 20.25 - 24.25 h; Heating / reflux; 2: With sodium carbonate in cyclohexane; water 3: S-methylisothiourea sulfate With 2,3-dicyano-5,6-dichloro-p-benzoquinone Product distribution / selectivity; more than 3 stages;