Microwave-Assisted Efficient synthesis of Dihydro Pyrimidines: Improved High Yielding Protocol for the Biginelli Reaction

Synthesis of Dihydropyrimidines: Isosteres of Nifedipine and Evaluation of Their Calcium Channel Blocking Efficiency

Hypertension and cardiovascular diseases related to it remain the leading medical challenges globally. Several drugs have been synthesized and commercialized to manage hypertension. Some of these drugs have a dihydropyrimidine skeleton structure, act as efficient calcium channel blockers, and affect the calcium ions' intake in vascular smooth muscle, hence managing hypertension. The synthesis of such moieties is crucial, and documenting their structure-activity relationship, their evolved and advanced synthetic procedures, and future opportunities in this area is currently a priority. Tremendous efforts have been made after the discovery of the Biginelli condensation reaction in the synthesis of dihydropyrimidines. From the specific selection of Biginelli adducts to the variation in the formed intermediates to achieve target compounds containing heterocylic rings, aldehydes, a variety of ketones, halogens, and many other desired functionalities, extensive studies have been carried out. Several substitutions at the C3, C4, and C5 positions of dihydropyrimidines have been explored, aiming to produce feasible derivatives with acceptable yields as well as antihypertensive activity. The current review aims to cover this requirement in detail.

An Efficient Synthesis of 3,4-dihydro-2(1H)-pyrimidinones from Aldehyde Bisulfite Adducts using Recyclable Wang Resin Supported Sulfonic Acid Catalyst

Abstract:

An efficient one-pot multicomponent synthesis of 3,4- dihydropyrimidin-2(1H)-ones has been developed from aldehyde bisulfite adducts, ethyl acetoacetate and urea using recyclable polymer- supported sulfonic acid catalyst. This new method provides several advantages over the previous synthesis, including high product yields, commercially viable, minimal workup operations and sustainable chemical practices.

Phosphotungstic Acid Catalysed One-Pot Synthesis of 5-Alkoxycarbonyl-4-Aryl-3,4-Dihydropyrimidin-2-Ones

5-Alkoxycarbonyl-4-aryl-3,4-dihydropyrimidin-2-ones are synthesised by the one-pot reactions of aldehydes, β-ketoesters and urea using a catalytic amount of phosphotungstic acid (PTA) in ethanol. The modified Biginelli cyclocondensation not only shortens the reaction period and simplifies the operation, but also improves the yields.

Preparation and chiral discrimination of R-(-)-2-phenylglycinol modified β-cyclodextrin

R-(-)-2-phenylglycinol monomodified β-cyclodextrin (β-CD) was synthesised under microwave irradiation. It displayed high chiral discrimination when it was complexed with amino acids.

An Efficient One‐Pot Biginelli Condensation of Aliphatic Aldehydes Catalyzed by Zinc Bromide under Solvent‐Free Conditions

Zinc bromide catalyzes the three component condensation reaction of an aldehyde, urea, and beta-ketoester or beta-diketone under solvent-free conditions to afford the corresponding dihydropyrimidinones (DHPMs) with moderate to high yields in short reaction time. The present method is very effective for the Biginelli condensation of aliphatic aldehydes.

Three-component, one-pot synthesis of 3,4-dihydropyrimidin-2-(1H)-ones catalyzed by bromodimethylsulfonium bromide

An efficient synthesis of 3,4-dihydropyrimidin-2-(1H)-one derivatives by one-pot three-component condensation reaction between an alkyl or aryl aldehyde, a 1,3-dicarbonyl compound, and urea or thiourea in the presence of catalytic amount of bromodimethylsulfonium bromide has been developed. The condensation product was obtained in excellent yields in refluxing ethanol and easily separated from the reaction mixture and purified.