- Using Methanol as a Formaldehyde Surrogate for Sustainable Synthesis of N-Heterocycles via Manganese-Catalyzed Dehydrogenative Cyclization
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The development of an efficient and sustainable synthetic route for formaldehyde production from renewable feedstock, especially in combination with a subsequent transformation to straightforwardly construct valuable chemicals, is highly desirable. Herein, we report a novel manganese-catalyzed dehydrogenative cyclization of methanol as a formaldehyde surrogate with a variety of dinucleophiles for facile synthesis of N-heterocycles. The in situ generated formaldehyde via catalytic methanol dehydrogenation can be selectively trapped by diverse dinucleophiles to avoid several possible side reactions. The utility of this transformation is further highlighted by its successful application to the synthesis of 13C-labeled N-heterocycles using 13CH3OH as a readily accessible 13C-isotope reagent.
- Li, Yibiao,Liu, Qiang,Shao, Zhihui,Yuan, Shanshan
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supporting information
(2022/02/23)
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- Condensation of Alkanediamines with Formaldehyde; Intramolecular Disproportionation of N-Hydroxymethyl Groups into N-Methyl and N-Formyl Groups
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The condensation of α,ω-alkanediamines NH2(CN2)nNH2 with aqueous formaldehyde has been studied by NMR spectroscopy of isolated products and of product mixtures.The condensation was reversible and gave products of widely different types depending on alkane chain length: bicyclic oxadiaza compounds (n = 2, 3, 4), a tricyclic tetraaza compound (n = 2), a quinquecyclic octaaza compound (n = 3), two-dimensional polymers (n = 4, 5).A slow irreversible rearrangement gave in two cases (n = 3, 4), unicyclic 1-formyl-3-methyl-1,3-diaza compounds.The condensation of N,N'-dimethyl-α,ω-alkandediamines CH3NH(CH2)nNHCH3 with aqueous formaldehyde was also studied.The reversible formation of simple unicyclic diaza compounds was observed in all cases (n = 2, 3, 4), but in one case (n = 2) there was again a slow irreversible rearrangement to the N-formyl-N,N'N'-trimethyl derivative.The rearrangement reaction involves a hydride shift and is strictly intramolecular.The conditions for its occurrence can be understood on a conformational basis.
- Dale, Johannes,Sigvartsen, Turid
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p. 1064 - 1070
(2007/10/02)
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