Synthesis of 6'-Substituted Dobutamine Analogues

Two 6'-substituted dobutamine analogues (1, 2) were synthesized from the coupling reaction of dopamine with the corresponding ketones. The ketone (8) was obtained from 4-nitrosalicyladehyde via 6 synthetic steps while the ketone (12) was prepared from 2-methyl-5-nitrobenzoic acid via 7 synthetic steps. Another synthetic attempts were also reported.