New imidazo[1,2-a]quinoxaline analogues have been synthesized in good yields via a bimolecular condensation of 2-imidazole carboxylic acid, followed by a coupling with ortho-fluoroaniline and subsequent substitution on the imidazole ring by Suzuki Cross-coupling reaction using microwave assistance. Antitumor activities of these derivatives were evaluated by growth inhibition of A375 cells in vitro. All compounds exhibited high activities compared to imiquimod and fotemustine used as references.

A short formal total synthesis of the marine natural product diazonamide A is described. The route is based on indole oxidative rearrangement, and a number of options were investigated involving migration of tyrosine or oxazole fragments upon oxidation of open chain or macrocyclic precursors. The final route proceeds from 7-bromoindole by sequential palladium-catalysed couplings of an oxazole fragment at C-2, followed by a tyrosine fragment at C-3. With the key 2,3-disubstituted indole readily in hand, formation of a macrocyclic lactam set the stage for the crucial oxidative rearrangement to a 3,3-disubstituted oxindole. Notwithstanding the concomitant formation of the unwanted indoxyl isomer, the synthesis successfully delivered, after deprotection, the key oxindole intermediate, thereby completing a formal total synthesis of diazonamide A.

Pyrazine derivatives R 0550New Imidazo[1,2-a]quinoxaline Derivatives: Synthesis and in vitro Activity Against Human Melanoma. -Imidazoquinoxaline analogues (XI) are synthesized via a bimolecular condensation of imidazole carboxylic acid (I), coupling of condensation product (II) with o-fluoroaniline (III), and subsequent substitution on the imidazole moiety by Suzuki cross-coupling under microwave assistance. The new strategy not only reduces the number of purification steps but also offers a new common route for the preparation of unsubstituted imidazoquinoxalines on the imidazole core starting from the unsubstituted carboxylic acid. It also permits the introduction of a substituent in the last steps of the procedure. The new analogues (XI) demonstrate high antitumor activities against human melanoma and can be considered as promising lead compounds. -(DELEUZE-MASQUEFA*, C.; MOARBESS, G.; KHIER, S.; DAVID, N.; GAYRAUD-PANIAGUA, S.; BRESSOLLE, F.; PINGUET, F.; BONNET, P.-A.; Eur.

Pin ups! The cover picture shows pin ups of the structure of marine natural product diazonamide A, the pivotal oxindole intermediate, and a post‐it showing the key disconnection into indole, oxazole and tyrosine fragments. More information can be found in the Full Paper by C. J. Moody, et al. on page 10867.