A multicomponent palladium-catalyzed carbonylative approach to imidazopyridinyl-N,N-dialkylacetamides

Veltri, Lucia; Russo, Patrizio; Prestia, Tommaso; Vitale, Paola; Romeo, Roberto; Gabriele, Bartolo

doi:10.1016/j.jcat.2020.03.026

Cited by 12 publications

(6 citation statements)

References 25 publications

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“…We started our study by synthesizing N ‐Boc‐(prop‐2‐yn‐1‐yl)thiazolamine 1 a by the reaction between commercially available 2‐aminothiazole with (Boc) 2 O followed by propargylation of the ensuing N ‐Boc‐2‐aminothiazole with propargyl bromide (see the Supporting Information for details). Considering the possibility of in situ N ‐deprotection under PdI 2 /KI‐catalyzed oxidative carbonylation conditions, already observed in other contexts, [6a,11] we used 1 a directly as possible model substrate for testing our work hypothesis, thus possibly avoiding an additional prior deprotection step. Substrate 1 a was initially allowed to react with CO (16 atm), diethylamine 2 a (3 equiv), and O 2 as the external oxidant (from air; 4 atm) in MeCN as the solvent (substrate initial concentration, 0.20 mmol of 1 a per mL of MeCN) at 100 °C in the presence of PdI 2 (1 mol%) and KI (1 equiv).…”

Section: Resultsmentioning

confidence: 99%

A Multicomponent Approach to Imidazo[2,1‐b]thiazole Derivatives by Sequential PdI₂/KI‐Catalyzed Deprotective Oxidative Aminocarbonylation – Dearomative Cyclization – Aromatization

et al. 2022

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Dedicated to Professor Cesare Gennari on the occasion of his 70th birthdayWe report a direct, multicomponent approach to an important class of fused-ring heterocycles, namely, imidazo[2,1-b]thiazole derivatives starting from simple and readily available building blocks (N-Boc-N-propargylthiazol-2-amines, carbon monoxide, a secondary amine, and oxygen). The process takes place under the catalysis of the simple PdI 2 /KI system under relatively mild conditions ( 100°C under 20 atm of a 4 : 1 mixture of CO-air), and leads to 2-(imidazo[2,1-b]thiazol-5-yl)-N,N-dialkylacetamides in yields up to 87 %. The mechanistic pathway leading to carbonylated imidazo[2,1-b]thiazole occurs through an ordered sequence of steps, involving amine-induced N-deprotection, oxidative aminocarbonylation of the triple bond (with CspÀ H activation and formation of a 2-ynamide intermediate), dearomative cyclization (by intramolecular conjugate addition of thioazolic nitrogen to the 2-ynamide moiety) and aromatization by proton-shift isomerization. When starting from N-Boc-N-(propargyl)benzo[d]thiazol-2-amine, tricyclic benzimidazothiazoles were formed in moderate yields.

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Section: Resultsmentioning

confidence: 99%

A Multicomponent Approach to Imidazo[2,1‐b]thiazole Derivatives by Sequential PdI₂/KI‐Catalyzed Deprotective Oxidative Aminocarbonylation – Dearomative Cyclization – Aromatization

et al. 2022

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“…To a cooled (0 °C) solution of Boc protected N ‐(prop‐2‐yn‐1‐yl)pyridin‐2‐amine [14] (6.10 mmol) [ N ‐Boc‐5‐methyl‐ N ‐(prop‐2‐yn‐1‐yl)pyridin‐2‐amine, 1.50 g; N ‐Boc‐3‐methyl‐ N ‐(prop‐2‐yn‐1‐yl)pyridin‐2‐amine, 1. 50 g; N ‐Boc‐6‐bromo‐ N ‐(prop‐2‐yn‐1‐yl)pyridin‐2‐amine, 1.90 g; N ‐Boc‐4‐chloro‐ N ‐(prop‐2‐yn‐1‐yl)pyridin‐2‐amine, 1.63 g; N ‐Boc‐5‐nitro‐ N ‐(prop‐2‐yn‐1‐yl)pyridin‐2‐amine, 1.69 g] in anhydrous CH 2 Cl 2 (6 mL), was added, under nitrogen, trifluoroacetic acid (6 mL, 78.4 mmol).…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Luminescent Fused Imidazole Bicyclic Acetic Esters by a Multicomponent Palladium Iodide‐Catalyzed Oxidative Alkoxycarbonylation Approach

et al. 2020

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A new multicomponent catalytic approach to important fused imidazole bicyclic acetic esters, whose core is present in many biologically active principles, is presented. It is based on the sequential cyclization‐alkoxycarbonylation‐isomerization of readily available N‐heterocyclic propargylamine derivatives, carried out under oxidative conditions using a simple catalytic system consisting of PdI2 (1 mol%) in conjunction with KI (1 equiv.), in the presence of AcONa as additive (1 equiv.) at 100 °C under 20 bar of a 4 : 1 mixture CO‐air. Under the optimized conditions, several N‐(prop‐2‐yn‐1‐yl)pyridin‐2‐amines were smoothly converted into alkyl 2‐(imidazo[1,2‐a]pyridin‐3‐yl)acetates in fair yields (51–77 %). The method was also applied to the conversion of N‐(prop‐2‐yn‐1‐yl)pyrimidin‐2‐amine into 2‐(imidazo[1,2‐a]pyrimidin‐3‐yl)acetate and of N‐(prop‐2‐yn‐1‐yl)pyrazin‐2‐amine into 2‐(imidazo[1,2‐a]pyrazin‐3‐yl)acetate. Some of the newly synthesized bicyclic derivatives have shown promising luminescence properties.

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“…Gabriele and co‐workers reported the carbonylative synthesis of substituted imidazopyridine derivatives 36 with the PdI 2 /KI catalyst system [140] . The multicomponent transformation involves the carbonylation of N ‐Boc‐protected pyridinamines 35 with secondary amines under oxidative conditions (4 : 1 CO/air mixture of 20 atm) [140a] . Rapid reactions afforded medium to excellent yields in short treatment (Scheme 117).…”

Section: Condensed Bicyclic Moleculesmentioning

confidence: 99%

Recent Advances in the Synthesis of Five‐membered Nitrogen Heterocycles Induced by Palladium Ions and Complexes

Molnár

2023

ChemistrySelect

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This review aims to collect and analyze recent results with respect to the use of varied palladium preparations in the synthesis of five-membered nitrogen heterocycles including condensed derivatives. Results have been selected with focus on studies of the last three years. Furthermore, a common feature of all methods treated here is that the nitrogencontaining five-membered ring is formed via ring closing of appropriate starting materials. Selected examples discussed will reveal that a plethora of products from small monocycles to condensed multi-ring systems can be successfully accessed. Major features are wide product ranges, high product yields and stereoselectivities often achieved under mild reaction conditions.

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A multicomponent palladium-catalyzed carbonylative approach to imidazopyridinyl-N,N-dialkylacetamides

Cited by 12 publications

References 25 publications

A Multicomponent Approach to Imidazo[2,1‐b]thiazole Derivatives by Sequential PdI₂/KI‐Catalyzed Deprotective Oxidative Aminocarbonylation – Dearomative Cyclization – Aromatization

A Multicomponent Approach to Imidazo[2,1‐b]thiazole Derivatives by Sequential PdI₂/KI‐Catalyzed Deprotective Oxidative Aminocarbonylation – Dearomative Cyclization – Aromatization

Synthesis of Luminescent Fused Imidazole Bicyclic Acetic Esters by a Multicomponent Palladium Iodide‐Catalyzed Oxidative Alkoxycarbonylation Approach

Recent Advances in the Synthesis of Five‐membered Nitrogen Heterocycles Induced by Palladium Ions and Complexes

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A multicomponent palladium-catalyzed carbonylative approach to imidazopyridinyl-N,N-dialkylacetamides

Cited by 12 publications

References 25 publications

A Multicomponent Approach to Imidazo[2,1‐b]thiazole Derivatives by Sequential PdI2/KI‐Catalyzed Deprotective Oxidative Aminocarbonylation – Dearomative Cyclization – Aromatization

A Multicomponent Approach to Imidazo[2,1‐b]thiazole Derivatives by Sequential PdI2/KI‐Catalyzed Deprotective Oxidative Aminocarbonylation – Dearomative Cyclization – Aromatization

Synthesis of Luminescent Fused Imidazole Bicyclic Acetic Esters by a Multicomponent Palladium Iodide‐Catalyzed Oxidative Alkoxycarbonylation Approach

Recent Advances in the Synthesis of Five‐membered Nitrogen Heterocycles Induced by Palladium Ions and Complexes

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A Multicomponent Approach to Imidazo[2,1‐b]thiazole Derivatives by Sequential PdI₂/KI‐Catalyzed Deprotective Oxidative Aminocarbonylation – Dearomative Cyclization – Aromatization

A Multicomponent Approach to Imidazo[2,1‐b]thiazole Derivatives by Sequential PdI₂/KI‐Catalyzed Deprotective Oxidative Aminocarbonylation – Dearomative Cyclization – Aromatization