What is the product of Biginelli reaction?

2019-06-19 by No Comments

What is the product of Biginelli reaction?

The Biginelli reaction is a multiple-component chemical reaction that creates 3,4-dihydropyrimidin-2(1H)-ones 4 from ethyl acetoacetate 1, an aryl aldehyde (such as benzaldehyde 2), and urea 3. It is named for the Italian chemist Pietro Biginelli.

Why urea is used in Biginelli reaction?

The most favorable pathway starts with the condensation of the urea and benzaldehyde, followed by the addition of ethyl acetoacetate. Remarkably, a second urea molecule catalyzes nearly every step of the reaction. Thus, the Biginelli reaction is a urea-catalyzed multicomponent reaction.

What is the catalyst used in Biginelli reaction?

The original Biginelli reaction is the three-component one-pot condensation of benzaldehyde (1), ethyl acetoacetate (2), and urea (3) in the presence of strong acid as catalyst to give substituted 3,4-dihydropyrimidin-2(1H)-one (4) (Scheme 1A).

Which intermediate is formed in synthesis of Dihydropyrimidinone?

The composition of the synthesized compounds (1–10) was confirmed by spectral and elemental data. The possible reaction mechanism involves the acid catalyzed formation of iminium ion intermediate from the substituted aryl aldehydes and urea.

Why is the Biginelli reaction important?

The Biginelli reaction involving a three-component condensation of aldehydes, urea or thiourea, and β-dicarbonyl compounds provides direct access to large collections of molecules in combinatorial syntheses.

Which compound is synthesized by Biginelli?

The Biginelli reaction, named after the Italian chemist Pietro Biginelli,112 is a three component condensation reaction between an aldehyde, a (thio)urea and an easily enolizable carbonyl compound, such as β-ketoester, allowing the synthesis of functionalized 3,4-dihydropyrimidin-2-(1H)ones or -thiones.

What is meant by multicomponent reaction?

Multicomponent reactions (MCRs) are one pot processes in which three or more reactants come together in a single reaction vessel to form a product containing substantial elements of all the reactants [82].

Is the example of multicomponent reaction?

The first reported multicomponent reaction was Strecker’s synthesis [113] of α-amino cyanides (166) in 1850 (Scheme 3.24). Strecker synthesis of α-amino cyanides. Another example of multicomponent reactions is Hantzsch’s pyrrole synthesis [114]. In this, pyrroles (167) are synthesized (Scheme 3.25).

What are five types of reactions?

In this lesson, students will be guided through definitions, generic formulas and actual chemical examples regarding the five types of reactions (i.e., synthesis, decomposition, single-replacement, double-replacement, and combustion).

What is the significance of the Biginelli reaction?

Biginelli Reaction. This acid-catalyzed, three-component reaction between an aldehyde, a -ketoester and urea constitutes a rapid and facile synthesis of dihydropyrimidones, which are interesting compounds with a potential for pharmaceutical application.

How is the dhpm produced in the Biginelli reaction?

However, the Biginelli product, i.e., the DHPM, was achieved only via the iminium route by condensation of 1,1′- (phenylmethanediyl)diurea intermediate 2 with ethyl acetoacetate.

How are Dihydropyrimidinones synthesized in Biginelli reaction?

Biginelli three-component cyclocondensation reaction of aldehydes, CH-acidic carbonyl compounds, and urea synthesized dihydropyrimidinones under strongly acidic conditions. Many improved methods used Lewis acids instead of traditional mineral acids under MW heating.

What kind of zeolite is used in Biginelli condensation?

Biginelli condensation catalyzed by Natural Heulandite type zeolite. H-ZSM-5 and HY zeolites have been reported in the Biginelli cyclocondensation, in refluxing toluene and during long reaction times, affording DHPMs 47 with moderated yields [130].