“…Amphimedine (1) Three total syntheses of amphimedine have been published.64-67 In addition, several papers have appeared outlining synthetic approaches to tetracyclic or pentacyclic alkaloid skeletons. [68][69][70][71][72] The first synthesis of amphimedine by Echavarren and Stille exploited an aza-Diels-Alder reaction and palladium-catalyzed cross coupling of aryl organostannanes with electrophilic aryl triflates (Scheme II64). The easily prepared quinoline 78 was converted to the corresponding 4-O-triflate 79 and condensed with the aryl stannane 80 in the presence of palladium(O), followed by refunctionalization to the trifluoroacetamide 81.…”
“…Amphimedine (1) Three total syntheses of amphimedine have been published.64-67 In addition, several papers have appeared outlining synthetic approaches to tetracyclic or pentacyclic alkaloid skeletons. [68][69][70][71][72] The first synthesis of amphimedine by Echavarren and Stille exploited an aza-Diels-Alder reaction and palladium-catalyzed cross coupling of aryl organostannanes with electrophilic aryl triflates (Scheme II64). The easily prepared quinoline 78 was converted to the corresponding 4-O-triflate 79 and condensed with the aryl stannane 80 in the presence of palladium(O), followed by refunctionalization to the trifluoroacetamide 81.…”
“…Almost all the members of pyridoacridine family of marine alkaloids are cytotoxic, and some exhibit specific properties such as inhibition of topoisomerase II, anti-HIV activity, Ca 2+ release activity, metal-chelating properties, or intercalation into DNA − and the efforts toward the synthesis of their polycyclic skeletons and related pyridoacridines are considerable. − Because of the importance that pyridoacridines have acquired since their discovery, a general synthetic route to pyridoacridines would be of great interest and potential utility in medicinal chemistry. …”
Section: Resultsmentioning
confidence: 99%
“…These compounds often exhibit an array of biological activities and a particular chemical behavior that have attracted the interest of many natural product chemists and biochemists. Since 1983, when the structure of amphimedine, the first of these marine alkaloids was reported, many additional examples have been described, and a number of papers have appeared describing synthetic efforts toward and the total synthesis of pyridoacridine alkaloids. − 1 …”
1-BOC-2-lithio-1,4-dihydropyridines were condensed with 3,4-disubstituted cyclobutenediones to produce 1,2-adducts. Neat thermolysis under oxygen-free conditions produced substituted 1,4-dihydroquinoline hydroquinones in which the tert-butoxy residue of the BOC group was displaced by a phenolic residue, generating an oxazolone ring that functioned to protect both rings of the dihydroquinoline hydroquinone from untimely oxidation. Oxidative aromatization with concomitant loss of the oxazolone ring was achieved using 2 equiv of o-chloranil in acetic acid and provided substituted quinoline quinones in good yields. By use of this strategy, a concise synthesis of the pyridoacridine ring system was achieved.
“…The problem is how strong this effect is and whether it hinders the cyclization. The failure in the synthesis of pyridoacridine by the Friedlaender reaction of 1 amino 4 methylacridone with acetylacetone have been attributed 9 to the conjugation of the imino group with the carbonyl one.…”
1 Acylamino 10 methylacridones in a polar aprotic solvent underwent base catalyzed cy clization into the corresponding 7 methyl 7H pyrido[2,3,4 kl]acridin 2(3H ) ones. Heating of 1 butylaminoacridone in acetic anhydride in the presence of p toluenesulfonic acid and potassium acetate afforded 3 butyl 7H pyrido[2,3,4 kl]acridin 2(3H ) one, while heating of 1 aminoacridone under the same conditions gave 9 acetoxy 1 acetylimino 1,10 dihydroxy acridine.
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