Calcium fluoride: an efficient and reusable catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and their corresponding 2(1H)thione: an improved high yielding protocol for the Biginelli reaction

Synthesis of 3,4‐Dihydropyrimidinones via Phase Transfer Catalysis

“…All the products were confirmed by comparing their melting points, IR, 1 H NMR and 13 C NMR data with literature data [1,16,30,[33][34][35][36][37][38].…”

“…This classical method often suffers from low yields of products in the case of substituted aromatic and aliphatic aldehyde . This has led to the recent disclosure of several one‐pot methodologies for the synthesis of dihydropyrimidinones derivatives involving the use of a number of catalysts such as CuCl 2 [22], ZrCl 4 , ZnBr 2 , LiBr , BiCl 3 , Cu(OTf) 2 , Yb(OTf) 3 , Bi(NO 3 ) 3 , PPh 3 , CaF 2 , YbCl 3 . However, many of these methods also suffer from drawbacks, such as the involvement of expensive reagents, harsh conditions and high reaction times.…”

Highly Regioselective Addition of Organozinc Reagents to 2‐Oxo‐1,2‐dihydropyrimidine‐5‐carboxylates Activated by BF3·OEt2: Synthesis of 2‐Oxo‐1,2,3,4‐tetrahydropyrimidine‐5‐carboxylates

“…More recently, the development of efficient chiral auxiliaries [2a,2b,12d–12g] or catalysts14 has led to the asymmetric synthesis of DHPMs. Although three‐component reactions (route a, Scheme ) for the construction of libraries of DHPMs through solution,7a–7e solvent‐free7f and solid‐phase7g–7l strategies are suitable for high‐throughput or combinatorial synthesis, the decoration of the preformed DHPM core by using the tools developed in our laboratory [8–11,12b,12d] have shown considerable potential for appending tailor‐made fragments at all possible (N‐1, C‐2, N‐3, C‐4, C‐5 and C‐6) diversity‐oriented centres by using simple starting materials. By using these tools, we have previously achieved both racemic7f,8 and diastereoselective12d,12e syntheses of DHPMs.…”

Immobilized nickel(II) on organic-inorganic hybrid materials: The effective and reusable catalysts for Biginelli reaction

“…After then, the Biginelli reaction for the synthesis of 3,4-dihydropyrimidin-2(1H)-one has received renewed interest and a number of improved procedures have been reported using different conditions, such as the classical reaction conditions, the microwave irradiation [4], solid phase reagents [5], and ionic liquids [6]. The reactions were generally carried out in the presence of Lewis acid catalysts, such as BF 3 ·OEt 2 /CuCl [7], CuI [8], Cu(OTf) 2 [9], Cu(BF 4 ) 2 [10], polyphosphonate ester (PPE) [11], In(OTf) 3 [12], InBr 3 , InCl 3 [13], LaCl 3 ·7H 2 O [14], La(OTf) 3 [15], Yb(OTf) 3 [16], ceric ammonium nitrate [17], Mn(OAc) 3 ·2H 2 O [18], BiCl 3 [19], LiClO 4 [20], CeCl 3 ·7H 2 O [21], Ce(NO 3 ) 3 ·6H 2 O [22], FeCl 3 ·6H 2 O and NiCl 2 ·6H 2 O/HCl [23], ZnCl 2 [24], ZrCl 4 and ZrOCl 2 ·8H 2 O [25], Sr(OTf) 2 [26], Bi(OTf) 3 [27], LiBr [28], NH 4 Cl [29], CaF 2 [30], Y(NO 3 ) 3 ·6H 2 O [31], PhB(OH) 2 [32], or SmI 2 [33] etc. Most recently, the application of Lewis base as the catalyst [34] and the asymmetric synthesis [35] for the Bignielli reaction have been investigated.…”