An Approach to the Construction of Benzofuran-thieno[3,2-b]indole-Cored N,O,S-Heteroacenes Using Fischer Indolization
Roman A Irgashev1,2, Nikita A Kazin1, Gennady L Rusinov1,2
1Postovsky Institute of Organic Synthesis, Ural Division, Russian Academy of Sciences, S. Kovalevskoy Str., 22, Ekaterinburg 620990, Russia.
ACS Omega
|December 6, 2021
Summary
Researchers developed a new synthetic route to benzofurothienoindoles using Fischer indolization. This method efficiently produces novel heterocyclic compounds from readily available precursors.
Area of Science:
- Organic Chemistry
- Heterocyclic Chemistry
- Medicinal Chemistry
Background:
- Benzofuro[2',3':4,5]thieno[3,2-b]indoles are a class of heterocyclic compounds with potential biological activities.
- Previous synthetic methods for these compounds were not efficient or direct.
Purpose of the Study:
- To develop a novel, efficient, and one-pot synthetic route for 6H-benzofuro[2',3':4,5]thieno[3,2-b]indoles.
- To explore alternative synthetic strategies when direct methods fail.
Main Methods:
- Synthesis of methyl 3-aminothieno[3,2-b]benzofuran-2-carboxylates from 3-chlorobenzofuran-2-carbaldehydes in three steps.
- Preparation of 3-chlorobenzofuran-2-carbaldehydes via Vilsmeier-Haack-Arnold reaction.
- One-pot Fischer indolization of methyl 3-aminothieno[3,2-b]benzofuran-2-carboxylates.
Main Results:
- Successfully synthesized a series of six 6H-benzofuro[2',3':4,5]thieno[3,2-b]indoles.
- Established a reliable three-step procedure for preparing key aminothienobenzofuran intermediates.
- Demonstrated the utility of Fischer indolization in constructing the target heterocyclic system.
Conclusions:
- The developed one-pot Fischer indolization offers an efficient method for synthesizing novel benzofurothienoindole derivatives.
- The synthetic route provides a valuable alternative to previously reported methods.
- This work expands the accessible chemical space for exploring potential therapeutic applications of these heterocycles.
More Related Videos
Related Concept Videos
01:11Electrophilic Aromatic Substitution: Friedel–Crafts Acylation of Benzene
7.7K
The Friedel–Crafts acylation reactions involve the addition of an acyl group to an aromatic ring. These reactions proceed via electrophilic aromatic substitution by employing an acyl chloride and a Lewis acid catalyst such as aluminum chloride to form aryl ketone.
7.7K
01:17Electrophilic Aromatic Substitution: Friedel–Crafts Alkylation of Benzene
7.1K
Friedel–Crafts reactions were developed in 1877 by the French chemist Charles Friedel and the American chemist James Crafts. Friedel–Crafts alkylation refers to the replacement of an aromatic proton with an alkyl group via electrophilic aromatic substitution. A Lewis acid catalyst such as aluminum chloride reacts with an alkyl halide to form a carbocation. The resulting carbocation then reacts with the aromatic ring and undergoes a series of electron rearrangements before giving the...
7.1K
01:18Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism
2.4K
Birch reduction uses solvated electrons as reducing agents. The reaction converts benzene to 1,4-cyclohexadiene. The reaction proceeds by the transfer of a single electron to the ring to form a benzene radical anion. This anion is highly basic—it abstracts a proton from the alcohol to form a cyclohexadienyl radical. Another single electron transfer gives the cyclohexadienyl anion. A proton transfer from the alcohol forms 1,4-cyclohexadiene. Since this reduction occurs via radical anion...
2.4K
![[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12417.jpg&w=3840&q=75)
01:16[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
10.9K
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
10.9K
01:29Diels–Alder Reaction: Characteristics of Dienes
4.5K
The Diels–Alder reaction brings together a diene and a dienophile to form a six-membered ring. Both components have unique characteristics that influence the rate of the reaction.
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is...
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is...
4.5K
01:20Electrophilic Aromatic Substitution: Nitration of Benzene
6.8K
The nitration of benzene is an example of an electrophilic aromatic substitution reaction. It involves the formation of a very powerful electrophile, the nitronium ion, which is linear in shape. The reaction occurs through the interaction of two strong acids, sulfuric and nitric acid.
6.8K