Synthesen von Mannich‐Basen von Hydroxy‐indolen. 3. Mitteilung über synthetische Indol‐Verbindungen [1]

Abstract

Summary. The reactivity of hydroxy-indoles under the conditions of the MANNICH-reaction has been studied. The electrophilic side-chain enters in each case in a position ortho to the phenolic group. 4-Hydroxy-indole is substituted in the 5-, 5-hydroxy-indole in the 4-, 6-hydroxy-indole in the 7-, and 7-hydroxy-indole probably in the 6-position. The structures of the MANNICH bases from Wie wir fanden, liefern 4-, 5-, 6-und 7-Hydroxy-indol mit aquimolaren Mengen Dimethylamin und Formaldehyd in Athanol je 1 MANNICH-Base, die nicht identisch war mit dern entsprechenden, bereits in der Literatur beschriebenen Hydroxy-gramin [l]. Die basische Seitenkette war also rnit grosser Wahrscheinlichkeit in eine der freien l) Zur Zeit der experimentellen Durchfuhrung dieser Arbeit lagen in der Literatur nur wenige Angaben uber MANNICH-Basen von Hydroxy-indolen vor, darunter noch keine von solchen mit freier 1-, 2-und 3-Stellung [6]. Seither sind einige weitere Arbeiten zu diesem Themenkreis bekanntgeworden [7] [8] [9], darunter auch die Herstellung von MANNICH-BaSen des 5-Hydroxyindols [9].

Organocatalytic Enantioselective Friedel–Crafts Alkylation/Lactonization Reaction of Hydroxyindoles with Methyleneoxindoles

“…The hydroxy group of phenols is a well‐known activating/directing group in organic chemistry . With the advent of organocatalysis, the organocatalytic asymmetric Friedel–Crafts reaction of phenols, especially naphthols, has attracted much attention in the last decade .…”

An antenna-sensitised 1-acyl-7-nitroindoline that has good solubility properties in the presence of calcium ions and is suitable for use as a caged l-glutamate in neuroscience

“…4-Hydroxy-5-methylindole 7 (5.00 g, 34 mmol; prepared as previously described 17 ) was added to a suspension of anhydrous K 2 CO 3 (7.05 g, 51 mmol) in acetone (400 mL). Methyl bromoacetate (10.40 g, 68 mmol) was added after 15 min and the mixture was heated under reflux for 5 h. The solid was filtered off, washed with acetone and the filtrate was evaporated.…”

Beiträge zur Chemie der 4‐Hydroxyindol‐Verbindungen 10. Mitteilung über synthetische indolverbindungen [1]

“…ABSystem beim fru her [6] hergestellten . Scharfe 1-ProtonSingulette bei 6 == 11,l in den Spektren von 5a und 5b deuten auf eine Oximgruppe in beiden Verbindungen.…”