New tetracyclic compounds containing the β‐carboline moiety

Abstract

Oxidation of 1‐methyl‐3‐methoxycarbonyl‐β‐carboline with selenium dioxide gave 1‐formyl‐3‐methoxycarbonyl‐β‐carboline II. Compound II reacted with acetic or propionic anhydride to give easily the 2‐methoxycarbonyl‐6H‐indolo[3,2,1‐d,e][1,5]naphthyridin‐6‐ones III; reaction of II with some primary amines led to the formation of the Schiff bases IV, which were reduced to the 1‐aminomethyl‐3‐methoxycarbonyl‐β‐carbolines V with sodium borohydride. Cyclization of V with aqueous formaldehyde led to the pyrimido[3,4,5‐lm]pyrido[3,4‐b]indoles VI. Analogously, cyclization with formaldehyde, acetone or 1,1′‐carbonyldiimidazole of the 3‐aminomethyl‐ 1,2,3,4‐tetrahydro‐β‐carbolines VIII, obtained by reaction of 3‐methoxycarbonyl‐1,2,3,4‐tetrahydro‐β‐carboline VII with amines followed by lithium aluminium hydride reduction of the resulting amides, gave the imidazo[1′,5′‐1,6]pyrido[3,4‐b]indoles IX and X. Dieckmann cyclization of 3‐methoxycarbonyl‐2‐[(3‐ethoxycarbonyl)‐1‐propyl]‐1,2,3,4‐tetrahydro‐β‐carboline XI led to a 1:1 mixture of the β‐ketoesters XII and XIII, which underwent deethoxycarbonylation to 5,6,8,9,10,11,11a,12‐octahydroindolo[3,2‐b]quinolizin‐11‐one XIV. Finally, the polyphosphoric acid (or esters) catalyzed cyclization of the N‐acyl derivatives XVI of 3‐hydrazinocarbonyl‐β‐carboline XV led smoothly to the 3‐(1,3,4‐oxadiazol‐2‐yl)‐β‐carbolines XVII.

1(3)‐Formyl‐β‐carbolines: Potential Aldo‐X Precursors for the Synthesis of β‐Carboline‐Based Molecular Architectures

“…The first synthetic derivativeo fK umujianC,m ethyl 1-formyl-9H-pyrido [3,4-b]indole-3-carboxylate (3), was prepared by Gatta and Misiti throughaSeO 2 -mediated oxidation of the C1 methyl group into af ormylg roup in differently substituted THbCs (2 and 4), as shown in Scheme 3. [24] Interestingly,m ethyl 1-formyl-9H-pyrido [3,4-b]indole-3-carboxylate (3)i sk nownt o display mild anti-HIV activity. [25] Bracher and Hildebrand achieved the first synthesis of naturally occurring KumujianC(7) [26] in 51 %y ield from the reaction of dimetalated b-carboline (6)w ith DMF as an electrophile (Scheme 4).…”

Synthesis of heteryl derivatives of 2,5-disubstituted 1,3,4-okasadiazole

“…У роботі [22] 1,3,4-оксадіазоли одержували цик-лізацією заміщених N,N'-діацилгідразидів β-кар-боліну 5 в середовищі ПФК нагріванням до 100-110 °С впродовж 3 годин (схема 2).…”

Fruitful Decades for Canthin-6-ones from 1952 to 2015: Biosynthesis, Chemistry, and Biological Activities

“…The canthin-6-one alkaloids have been synthesized via different approaches by many researchers [2,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75]. In order to use these methods to guide our review more clearly, we categorized classic and efficient synthetic methods according to their key reaction steps.…”

“…The use of the Perkin reaction to synthesize canthin-6-one alkaloid analogs was reported by Giudice et al in 1990 (Scheme 7) [75] and, more recently, by Brahmbhatt et al in 2010 [42]. Despite the relatively low overall yield (48.96% for 29 and 46.24% for 30 ), the synthesis strategy is relatively simple and low-cost.…”