Manganese dioxide mediated one-pot synthesis of methyl 9H-pyrido[3,4-b]indole-1-carboxylate: Concise synthesis of alangiobussinine

Abstract

SummaryThe carboline ring system is an important pharmacophore found in a number of biologically important targets. Development of synthetic routes for the preparation of these compounds is important in order to prepare a range of analogues containing the carboline heterocyclic moiety. A manganese dioxide mediated one-pot method starting with an activated alcohol and consisting of alcohol oxidation, Pictet–Spengler cyclisation, and oxidative aromatisation, offers a convenient process that allows access to β-carbolines. This one-pot process for the preparation of methyl 9H-pyrido[3,4-b]indole-1-carboxylate has subsequently been used as the key step in the synthesis of alangiobussinine and a closely related analogue.

In VitroInhibitory and Cytotoxic Activity of MFM 501, a Novel Codonopsinine Derivative, against Methicillin-ResistantStaphylococcus aureusClinical Isolates

“…Furthermore, MFM 501 has a good yield of 20 to 60% as exemplified by the other similar pyrrolidine compounds previously reported using a one-pot reaction [ 22 ]. Besides giving out good yield of intended compounds, the advantages of one-pot reaction schemes include reduction of the time required to set up the reactions, removal of the need to isolate unstable intermediates, and reduction of the time required for purifications which would lead to lowering the cost of overall reaction and lessening wastage to the environment [ 49 , 50 ].…”

Cyclic Imines in Ugi and Ugi-Type Reactions

“…In 2011, the total synthesis of alangiobussinine was reported by Sutcliffe et al in four steps from tryptamine. Their strategy contains long reaction time and tedious steps with 27% overall yield . Recently, Srivastava et al reported an interesting reaction for the total synthesis of alangiobussinine 91 in two steps with 45% overall yield.…”

“…Their strategy contains long reaction time and tedious steps with 27% overall yield. 107 Recently, Srivastava et al reported an interesting reaction for the total synthesis of alangiobussinine 91 in two steps with 45% overall yield. This simple and short approach contains IBX-mediated oxidative JU-3CR, followed by another oxidation reaction (Scheme 24).…”

β-Carboline Amides as Intrinsic Directing Groups for C(sp2)–H Functionalization

“…Our investigations commenced with studies on the directed alkynylation of alangiobussinine ( 2a ), which was prepared in a single step from the known β-carboline-1-methyl ester 1 by activation of the ester moiety using 2-hydroxypyridine under aerobic conditions (eq ). Our preparation of 2a from 1 is an improvement in terms of step count and isolated yield over the previously reported synthesis of this natural product . Applying this 2-hydroxypyridine-mediated amidation method, a variety of other β-carboline amide derivatives were accessed in good yields from the corresponding arylethamines.…”