Sulphamic Acid (H2NSO3H) Catalysed One Pot Synthesis of 3,4-Dihydropyrimidin-2(1h)-Ones and their Thione Analogues

Sulphamic Acid (H2NSO3H)‐Catalyzed Multicomponent Reaction of β ‐Naphthol: An Expeditious Synthesis of Amidoalkyl Naphthols

“…17 In our attempt to further explore the role of sulphamic acid as an acid catalyst in other carbon-carbon and carbon-heteroatom bond forming reactions, we demonstrated the use of SA as a catalyst for the synthesis of 3,4-dihydropyrimidines. 18 In continuation of our work on sulphamic acid, in this paper we have demonstrated the use of sulphamic acid as a mild and efficient catalyst for synthesis of α-amidoalkyl-β-naphthols by multicomponent condensations of β-naphthol with aromatic aldehydes and urea or amides.…”

Al(HSO4)3and Al2O3-SO3H as Efficient Catalysts for Modified Preparation of 3,4-Dihydropyrimidin-2 (1H)-ones/thiones

“…7 In order to improve the efficiency of Biginelli reaction, a number of catalysts have been developed. These include ammonium chloride, 8 ZrCl 4 or ZrOCl 2 , 9 vanadium(III) chloride, 10 chloroacetic acid, 11 graphite-supported lanthanum chloride, 12 alkylammonium and alkylimidazolium perhaloborates, phosphates, and aluminates, 13 1,1,3,3-tetrametylguanidinium trifluoroacetate, 14 ferric chloride and boric acid, 15 sulphamic acid, 16 tetrabutyl ammonium hydrogensulfate, 17 and polyphosphate ester (PPE). 18 However, many of these methods suffer from the drawbacks inconsistent with green chemistry, such as the use of toxic chemicals and heavy metals.…”

Oxalic acid as a versatile catalyst for one pot facile synthesis of 3,4‐dihydropyrimidin‐2‐(1H)‐ones and their thione analogues

“…Biginelli [4] reported the first synthesis of dihydropyrimidines by a simple one-pot condensation reaction of ethyl acetoacetate, benzaldehyde and urea. We have recently reported sulphamic acid as a catalyst for preparing DHPMs [7]. The use of different Lewis acid has attempted such as FeCl 3 , BF 3ethrate, LaCl 3 , ZnCl 2 , ZrCl 4 , BiCl 3 etc [5].…”