Synthesis and in vitro biological evaluation of novel coumarin derivatives containing isoxazole moieties on melanin synthesis in B16 cells and inhibition on bacteria.

A novel series of coumarin derivatives 6a-o, bearing isoxazole moieties were designed and synthesized. After that, they were evaluated for melanin synthesis in murine B16 cells and inhibitory effect on the growth of CA (Candida albicans), EC (Escherichia coli), SA (Staphylococcus aureus). It was found that eleven compounds (6b-f, 6j-o) showed a better activity on melanin synthesis than positive control (8-MOP). Among them, compounds 6d (242%) and 6f (390%), with nearly 1.6 and 2.6-fold potency compared with 8-MOP (149%) respectively, were recognized as the most promising candidate hits for further pharmacological study of anti-vitiligo. Seven halogen substituted compounds exhibited moderate antimicrobial activity against CA. It is interesting that 6e-f and 6l-m, which had two halogens on the benzene showed a comparable activity with Amphotericin B against CA. The evaluation of melanin synthesis in B16 cells and inhibitory effect on bacteria of above structurally diverse derivatives had also led to an outline of structure-activity relationship.

Synthesis and biological evaluation of furocoumarin derivatives on melanin synthesis in murine B16 cells for the treatment of vitiligo.

Furocoumarins, isolated from Psoralen corylifolia L., were found to be the most effective drug in the treatment of vitiligo nowadays. Twenty-five furocoumarin derivatives were thus designed and synthesized in order to improve the melanogenesis in B16 cells for the first time. Among them, twenty-three compounds were more potent than the positive control (8-MOP), the commonly used drug for vitiligo in clinic. Noticeably, compounds 6m (350.5%) and 6p (313.1%) based on the scaffold of 6k (2H-benzofuro[2,3-h]chromen-2-one) were nearly 3-fold stronger than 8-MOP (114.50%). The in vitro melanin synthesis evaluation of these structurally diverse analogues had also led to an outline of structure-activity relationship.

Reaction of ß-lactam carbenes with 2-pyridyl isonitriles: a one-pot synthesis of 2-carbonyl-3-(pyridylamino)imidazo[1,2-a]pyridines useful as fluorescent probes for mercury ion.

The one-pot reaction of ß-lactam carbenes with 2-pyridyl isonitriles followed by an acidic hydrolysis was reported, which produced 2-carbonyl-3-(pyridylamino)imidazo[1,2-a]pyridines in moderate to good yields. Among the resulting novel imidazo[1,2-a]pyridine derivatives, 1-(6-chloro-3-(5-chloropyridin-2-ylamino)imidazo[1,2-a]pyridin-2-yl)-2-ethylbutan-1-one was demonstrated to be an efficient fluorescent probe for mercury ion both in acetonitrile and in buffered aqueous solution.