Syntheses and evaluation of multicaulin and miltirone-like compounds as antituberculosis agents

Four multicaulin and miltirone-like phenanthrene derivatives were synthesised and evaluated as antituberculosis agents. The crucial step of the synthesis was Pschorr coupling of 4-(3-isopropyl-4-methoxyphenyl)-2-(2-aminophenyl)ethane (13) to give 2-isopropyl-3-methoxy-9,10-dihydrophenanthrene (9) and 4-isopropyl-3-methoxy-9,10-dihydrophenanthrene (9a). Compound 9 was converted to multicaulin and miltirone-like phenanthrene derivatives by further reactions. The best antituberculosis activity was exhibited by 2-isopropylphenanthrene-3-ol (11).