ChemInform Abstract: ELECTROCHEMICAL SYNTHESIS OF β‐OXOTRYPTOPHAN

Abstract

Durch Elektroreduktion der Isonitrosoverbindung (IV) in phosphatgepuffertem wäßrigen Methanol (Anolyt gesättigte Na2SO4‐LÖsung, Glasdiaphragma; Hg‐Kathode, Pt‐Anode) läßt sich in guter Ausb. die Titelverbindung (V) darstellen; (V) liegt wie sein Ethylester (VI) in Lösung im Gleichgewicht mit einem H‐brückenstabilisierten tautomeren Enol des Typs (VII) vor (1H‐NMR‐Spektrum).

The synthesis of some 3‐acylindoles revisited

“…Moreover, the 1 H NMR data featured only one acidic hydrogen signal, whereas the 13 C NMR and IR spectra suggested the presence of two different carbonyl functionalities, namely one ketonic and one amidic. Based on these data, the product was assigned the previously described unsymmetrical bisindole structure 7 [17]. There were no indications of keto-enol tautomerism in any of the NMR spectra.…”

“…Workup as above, followed by suspension of the crude complex product mixture in 2-propanol give a solid material, which was finally subjected to repeated crystallizations from acetonitrile/ DMF providing small amounts of 7 (1.5 g, 5%) as a white crystalline solid, mp 246-248 °C (lit. [17] Treatment of indole with malonic acid in acetic anhydride. A suspension of malonic acid (3.12 g, 30 mmol) in acetic anhydride (30 mL) was heated to 85 °C for 10 min.…”