Methylene-10,10'bis[(+)N_a-norvallesamidine], Dichlorure de Methylene N_b,N_b'[Bis(+)meloninium], Chlorures de N_b'-Chloromethyl Celastromelinium et Celastromelidinium: Alcaloïdes Dimeres, Artefacts Possibles d'Extraction de Melodinus celastroides

Recent progress in the chemistry of indole alkaloids and mould metabolites

“…The first of these, methylene Nb,Nb,bis[( + )-meloninium]dichloride (444), can be cleaved by hot potassium hydroxide to (+)-melonine (445), and can be partially synthesized by the reaction of (+)-melonine with diiodomethane, followed by anion exchange (Scheme 57). 204 The two other quaternary salts, (446) and (447), clearly arise by reaction of the corresponding tertiary bases with methylene chloride and can be degraded to these bases, celastromeline (448) and celastromelidine (449), by thermal decomposition in ethanolamine. Celastromeline and celastromelidine represent two modes of condensation of A'*-vincane with (+)-melonine.…”

Structure Reassignment of Melonine and Quantum-Chemical Calculations-Based Assessment of Biosynthetic Scenarios Leading to Its Revised and Original Structures

“…Several MIA scaffolds previously reported from M. philliraeoides, viz., aspidospermidine, norvallesamidine, kopsinine, and eburnane, are thought to have their biosynthesis proceed from such intermediates, strengthening this putative scenario . Wenkert proposed that aspidospermidine-type MIAs in particular were obtained following transannular cyclization of an iminium derivative of quebrachamine, designated as A in Scheme .…”

“…The so-called melonine core 2 has been described only once since then, also in M. philliraeoides by the same authors, in melonine-containing dimers . Published in 1991, those structures did not benefit from 2D NMR sequences to ascertain the constitution of their melonine component .…”

“…The so-called melonine core 2 has been described only once since then, also in M. philliraeoides by the same authors, in melonine-containing dimers. 7 Published in 1991, those structures did not benefit from 2D NMR sequences to ascertain the constitution of their melonine component. 7 Although highly atypical, the absence of the two-carbon side chain expected on the basis of the tryptophan precursor occurs in a few MIAs such as the apparicine and uleine subclasses.…”

“…7 Published in 1991, those structures did not benefit from 2D NMR sequences to ascertain the constitution of their melonine component. 7 Although highly atypical, the absence of the two-carbon side chain expected on the basis of the tryptophan precursor occurs in a few MIAs such as the apparicine and uleine subclasses. 8 However, unlike melonine, the determination of those structures benefited from modern spectroscopic means, and both structures were unambiguously validated by total synthesis.…”