An improved synthesis of the alkaloid Luotonin-A employing ionic liquid and water as key solvents

Synthesis of C-Ring-Substituted Vasicinones and Luotonins via Regioselective Aza-Nazarov Cyclization of Quinazolinonyl Enones

“…This increased attention is partly due to toxic side effects associated with the hydrolyzable lactone E -ring of CPT that could be alleviated with luotonin’s highly stable benzo E -ring. To date, several reports have appeared on total synthesis and structural modifications of luotonin A in an effort to find a more potent lead. , The synthetic modifications reported thus far on the luotonin A core include principally alkyl and haloalkyl substituents on the A-ring; , aryl, alkyl, aminoalkyl, and trifluoromethyl substituents on the B-ring; and halo, trifluoromethyl, and phenyl substituents on the E-ring …”

Effective and Sustainable Access to Quinolines and Acridines: A Heterogeneous Imidazolium Salt Mediates C–C and C–N Bond Formation

“…Methyl 2‐Methylquinoline‐3‐carboxylate (3bc): Pale yellow solid; purification by column chromatography (hexane/ethyl acetate, 8.0:2.0), 75 % yield; m.p. : 57–59 °C (AcOEt) [Lit.…”

Total and Diverted Total Synthesis of Pyrrolo‐Quinazolinone Alkaloids and Their Analogues

“…[16] This resemblance to CPT in structure and activity prompted development of impressive synthetic routes to access luotonin A and its analogues with the hope and possibility of obtaining better antitumor leads as it showed increased chemical stability than CPT and did away with the toxicity associated with ring opening of CPT and its analogues. [17] Owing to their impressive biological activities, there have been quite a few reports on synthesis of vasicinone and luotonin A, such as enzyme-catalyzed asymmetric synthesis [18] and solid-phase synthesis [19][20] for vasicinone, Pd-assisted biaryl coupling reaction, [21][22][23] Mitsunobu condensation, [25][26][27] Diels-Alder reaction [28][29] and free radical cyclization [29][30][31] for luotonin A, and 4,9-dihydro-β-carboline chemistry [32][33][34][35][36][37][38][39][40] electrochemistry, [41] and transition metal catalysis chemistry for other quinazolinone alkaloids. [42] As a part of our ongoing efforts to develop natural products based novel anti-microbial leads, we have initiated a quinazolinone based medicinal chemistry research program.…”