Cledera, PilarSánchez Cebrián, Juan DomingoCaballero, EsmeraldaYates, TamaraRamírez, Elena G.Avendaño López, María CarmenRamos García, María TeresaCarlos MenéndezMenéndez Ramos, José Carlos2026-02-272026-02-272007Cledera, Pilar, et al. «Microwave-Assisted, Solvent-Free Synthesis of Several Quinazoline Alkaloid Frameworks». Synthesis, vol. 2007, n.o 21, noviembre de 2007, pp. 3390-98. DOI.org (Crossref), https://doi.org/10.1055/s-2007-990818.10.1055/s-2007-990818https://hdl.handle.net/20.500.14352/133517Microwave irradiation leads to a considerable improvement of the cyclocondensation between anthranilic acid and lactim ethers derived from piperazine-2,5-diones in terms of reaction times, yields, and stereocenter integrity. This reaction has been used to prepare some derivatives of the pyrazino[2,1-b]quinazoline-3,6-dione system present in many quinazoline alkaloids. It could also be applied to the synthesis of compounds containing the complete hexacyclic ring system of the anti-MDR natural product N-acetyl¬ardeemin, and other comprising the pentacyclic framework of circumdatin E. The microwave-assisted reaction was also much better than the thermal one when applied to a bis-lactim ether, leading to the corresponding pentacyclic pyrazino[2,1-b:5,4-b′]diquinazoline-8,16-dione in excellent yield.engAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/journal articlehttps://doi.org/10.1055/s-2007-990818metadata only access547Microwave irradiationLactim etherAlkaloidsAntitumor agentsHeterocyclesQuímica orgánica (Química)2306 Química Orgánica