Microwave‐Assisted Construction of Pyrrolopyridinone Ring Systems by Using an Ugi/Indole Cyclization Reaction

Abstract

A series of pyrrolopyridinones were prepared by using N‐Boc‐pyrrole‐2‐carbaldehyde as a starting material in an Ugi reaction followed by an acid‐mediated indole cyclization to result in the formation of a new C–C bond. Changes to the other starting materials in this Ugi/indole cyclization reaction sequence extended the scope of this method to include a nucleophilic substitution reaction and an Ugi/deprotection/cyclization (UDC) strategy, which provided access to two new series of heterocyclic compounds. This method represents a facile and efficient one‐pot procedure for the preparation of pyrrolopyridinones under acidic conditions.

Dieckmann Condensation of Ugi N-Acylamino Amide Product: Facile Access to Functionalized 2,2-Disubstituted Indolin-3-ones

“…During the past few years of focusing on MCRs for the synthesis of nitrogen-containing heterocycles, we uncovered a novel synthetic strategy to access unique 2,2-disubstituted indolin-3-ones with a quaternary carbon center through Ugi, Dieckmann condensation cascade sequence (Scheme ). This new facile, Ugi/Dieckmann reaction extends to indolin-3-one fused pyrazino only changing Ugi acid input to bromoacetic acid.…”

Microwave-assisted efficient and facile synthesis of tetramic acid derivatives via a one-pot post-Ugi cascade reaction

“…In a similar manner as described in [38] the reactions were conducted as follows: To a magnetically stirred solution of ethyl glyoxylate (1.0 mmol) in MeOH (1.0 mL) was added the amine (0.5 mmol) in a 5 mL microwave vial, and the resulting solution was stirred at room temperature for 10 min. The acid (0.50 mmol) and the isocyanide (0.50 mmol) were then added separately.…”

“…In recent years, we used the Ugi four-component reaction as a main tool to generate nitrogen-containing heterocycles [38,39]. Spatz' team reported a novel two-step synthetic procedure for the preparation of substituted tetramic acid derivatives via an Ugi/Dieckmann reaction [40].…”

Multicomponent Approach to a Library of N-Substituted γ-Lactams

“…Furthermore, recognizing the potential for discovery of novel bioactive small molecules based upon the γ-lactam core structure, several research groups have presented interesting multicomponent or cascade approaches toward functionalized γ-lactams. − Multicomponent reactions (MCRs) were found to be an excellent tool to rapidly access a large and versatile drug-like chemical space to address the corresponding biological space …”