Hydroxylamin‐Derivate, XXXVII. Hydroxylamine in der Vierkomponenten‐Kondensation nach Ugi

Abstract

Hydroxylamin und seine N‐ und/oder O‐Alkylderivate lassen sich im sauren wäßrig‐alkoholischen Medium nach dem Syntheseprinzip der Vierkomponenten‐Kondensation (Ugi‐Reaktion) mit Aldehyden und Isocyaniden zu α‐Hydroxylamino‐carbonsäureamiden (4, 6, 8) (bzw. mit N‐Isocyan‐dialkylaminen zu α‐Hydroxylamino‐carbonsäurehydraziden 13) umsetzen. Aus Hydroxylaminen mit freier H2N‐Gruppe erhält man in bestimmten Fällen fast ausschließlich Produkte einer „doppelten”︁ Ugi‐Reaktion (9, 14).

Nitrile N-Oxides and Nitrile Imines as New Fuels for the Discovery of Novel Isocyanide-Based Multicomponent Reactions

“…After the disclosure of the Ugi reaction, imine surrogates were systematically evaluated in the reaction with isocyanides and carboxylic acids. For example the amine was substituted by hydroxylamines, 5 hydrazones, 6 hydrazines, 7 N-acylhydrazones, 8 diaziridine, 9 urea, 10 semicarbazones, 11 N-alkylated quinolines, 12 and later nitrones. 13 Over the last few…”

“…Indeed, it was well known that hydroxylamine was an untamed amine component in the Ugi and related multicomponent reactions, due to its three nucleophilic sites. 5 Furthermore hydroxylamine reacts very quickly and exothermically with nitrile N-oxides, and low temperatures are necessary to give satisfactory yields. 34 After optimization of the reaction conditions, we obtained the aminodioxime 44 in 72% yield just by mixing (Z)phenylchloroxime (14), pentyl isocyanide (25), and hydroxylamine (43) in dichloromethane at room temperature, using sodium hydrogen carbonate as the base (Scheme 9).…”

Synthesis of Heteroarylogous 1H-Indole-3-carboxamidines via a Three-Component Interrupted Ugi Reaction

“…Indeed, following studies on the mechanism of the Ugi reaction, 2 different strategies have been disclosed over the last decades for the identification of novel true isocyanidemediated MCRs. 3 For example, shortly after the disclosure of the four-component Ugi reaction, Ugi-like transformations using surrogates of amines (hydroxylamine, 4 hydrazine 5 ) or carboxylic acids (HN 3 , 6 HNCO 7 ) were reported, affording novel molecular frameworks. Apart from the use of bifunctionalized substrates in the Ugi reaction, only over the past few years have intellectually deeper approaches been systematically searched for and found.…”

Cyanogen Bromide as Dehydrosulfurizing Agent for the Synthesis of Nβ-Fmoc-Amino Alkyl Isonitriles from Nβ-Fmoc-Amino Alkyl Thioformamides

“…26 Amino acid ester derived isonitriles are the known entities, which are prepared from corresponding formyl amino acid esters. 27 A recent entry into this new class of amino acid derived isonitriles has been described by our group wherein N bFmoc amino alkyl isonitriles were obtained through carboxyl group modification.…”