A microwave-promoted three-component one-pot reaction has been developed to provide access to the core pyrazino[2,1-b]quinazoline-3,6-dione (1) scaffold, which is common to several families of alkaloids with significant biological activities. By adapting this synthetic strategy through the use of selected Boc-amino acids and amino acid esters, we have accomplished highly efficient and concise total syntheses of glyantrypine (2), fumiquinazoline F (3), and fiscalin B (5), achieving overall yields of 55, 39, and 20%, respectively.

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[reactions: see text] One-pot total syntheses of the quinazolinobenzodiazepine alkaloids sclerotigenin (1), (+/-)-circumdatin F (2), and (+/-)-asperlicin C (3) via novel microwave-assisted domino reactions were achieved in 55%, 32%, and 20% yields, respectively, from commercially available starting materials. A two-step total synthesis of (+/-)-benzomalvin A (4) was accomplished with an overall yield of 16%. Additionally, analogues of circumdatin E were synthesized via the three-component one-pot sequential reactions promoted by microwave irradiation. Finally, a two-step formal total synthesis of (+/-)-asperlicin E (5) was also realized by using this microwave-assisted protocol.

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Alkaloids U 0600Three-Component One-Pot Total Syntheses of Glyantrypine, Fumiquinazoline F, and Fiscalin B Promoted by Microwave Irradiation. -A highly efficient approach to glyantrypine (IVa), fumiquinazoline F (VIa), fiscalin B (VIb), and related compounds is reported. Unfortunately, partial epimerization takes place. -(LIU*, J.-F.; YE, P.; ZHANG, B.; BI, G.; SARGENT, K.; YU, L.; YOHANNES, D.; BALDINO, C. M.; J. Org. Chem. 70 (2005) 16, 6339-6345; Div. Chem.

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Alkaloids U 0600Microwave-Assisted Concise Total Syntheses of Quinazolinobenzodiazepine Alkaloids. -A number of title alkaloids such as sclerotigenin (IIIa), circumdatin F (IIIb), and asperlicin C (IIId) as well as related compounds like (VII) is prepared via novel microwave-promoted one-pot domino reactions. -(LIU*, J.-F.; KASELJ, M.; ISOME, Y.; CHAPNICK, J.; ZHANG, B.; BI, G.; YOHANNES, D.; YU, L.; BALDINO, C. M.; J.