A one-pot Biginelli synthesis of 3,4-dihydropyrimidin-2-(1H)-ones/thiones catalyzed by triphenylphosphine as Lewis base

One-pot three-component synthesis of 4-aryl-3,4-dihydro-pyrimidin-2(1<i>H</i>)-thiones catalyzed by Ni loaded SiO₂

“…The reaction of methyl 3-oxopentanoate and thiourea with o-methyl, m-methyl and m,p-dimethyl benzaldehyde produce the corresponding products in 84%, 82% and 86% yields, respectively, with 'longer' reaction time (3 h) ( Table 2, entries 13 and 15). (12 …”

“…However, this method often suffers from drawbacks such as harsh conditions, long reaction times and low yields, particularly when aliphatic and substituted aromatic aldehydes are used. Recently, several synthetic procedures for preparing of DHPMs have been reported, such as the use of a number of Lewis acid catalysts as well as protic acids including Y(NO 3 ) 3 .6H 2 O [8], Cu(BF 4 ) 2 [9], KAl(SO 4 ) 2 .12H 2 O [10], Mg(ClO 4 ) 2 [11], triphenylphosphine [12], Ca(NO 3 ) 2 [13], and H 3 BO 3 [14]. In addition, microwave irradiation [15], ultrasound irradiation [16], and ionic liquid [17] have also been utilized to improve and modify this reaction.…”

One-pot solvent free synthesis of dihydropyrimidinones using calcined Mg/Fe hydrotalcite catalyst

“…13 However, this reaction usually required harsh reaction condition, long reaction time and afford low yield. To overcome those disadvantages, improved procedure with different type of catalytic system and conditions such as PPh3, 14 Zeolite, 33 HCOOH, 34 and classical conditions including microwave irradiation, 35 and so on. However, above mention methods have potential utility, in spite of these many methods suffer from drawbacks such as use of expensive reagent, volatile strong acidic condition, high temperature, long reaction time, unsatisfactory yields and non-recyclable catalyst.…”

Synthesis of novel dihydropyrimidin-2(1h)-ones derivatives using lipase and their antimicrobial activity

“…Debache et al 8 investigated the use of triphenylphosphine as a Lewis base catalyst for the synthesis of DHPMs derivatives. It has been also reported by using imidazole based ionic liquids (ILs) such as water tolerant Lewis acid [ Use of the ILs as a reaction medium for biocatalysis has attracted great attention in recent years, as the processes are green and the ILs have several advantages compared to conventional reaction media [11][12][13][14] .…”