Synthesis of some new bis-3,4-dihydropyrimidin-2(1H)-ones by using silica-supported tin chloride and titanium tetrachloride

Silica-supported tin chloride and titanium tetrachloride were prepared by the reaction of tin chloride and titanium tetrachloride with activated silica gel in refluxing toluene.These solid acids have been employed as the catalysts for the synthesis of bisdihydropyrimidin -2(1H)-ones from aromatic dialdehydes,1,3-dicarbonyl compounds and urea at 90℃under solvent-free conditions.

Synthesis, Crystal Structure, Antibacterial Activities and Theoretical Computation of 3-(2-Hydroxybenzly)-4-(4-isopropylbenzyl- ideneamino)-(1H)-1,2,4-triazole-5-thione

The title compound C18H18N4OS has been synthesized by the reaction of 3-（2-hydroxy- benzyl）-4-amino-（1H）-1,2,4-triazole-5-thione with 4-isopropylbenzaldehyde in ethanol and characterized by IR, ^1H NMR spectra and elemental analysis. Its structure was determined by X-ray diffraction analysis. The crystal belongs to monoclinic, space group P21/c with a = 11.605（2）, b = 7.401（1）, c = 20.339（2） A, β= 103.05（2）°, V= 1701.8（4） A^3, Z = 4, Mr = 338.42,μ = 0.202 mm^-1, Dc = 1.321 g/cm^3 and F（000） = 712. The structure was solved by direct methods and refined to R = 0.0428 and wR = 0.1069. Due to the intramolecular O-H…N hydrogen bond and π-π stacking interactions between the benzene （C（1）～C（6）） and triazole rings, the two planes are essentially coplanar. Their biological activities have been measured, showing this type of compound has certain antibacterial activity for Staphylococous aureus and Bacillus subtilis. Based on the quantum chemistry calculation at the RHF/6-31G level, the frontier orbitals and electrostatic potential of the title compound were also discussed.

Synthesis and Crystal Structure of α-(3-Phenylureido)-α-(2,4-Dichlorophenyl) Methyl Phenylphosphinic Acid

The crystal structure of a (3-phenylureido)-a (2, 4-dichlorophenyl)methyl phenylphosphinic acid, C20H17Cl2N2O3P, Mr= 435. 25,which was obtained bydesulphurisation of cis-3, 4-dipheny1-5- (2, 4-dichlorophenyl ) -1, 3, 4-diazaphospholidin2-thione-4-oxide utilizing Ag+ -H2O system in a yield of 89%, is reported. It crystallizes in orthorhombic space group Pca21 with a= 11. 286(2), b= 20. 601 (4) f c=8. 695(2)A, V= 2021 (1) A3, Z= 4, D.= 1. 430 g/cm3, p=4. 21 cm-1, F(000) =896.The final R factor is 0. 040 and Rw is 0. 045 for 946 unique observed reflections[I>3a(I)]. The result of X-ray analysis indicates that the molecules in the crystal are linkedtogether by the O(3 ) ...H (2d) - N (2d ) intermolecular hydrogen-bondings.

布朗斯特酸性离子液体[DC2O2IM][p-CH3PhSO3]催化Biginelli三组分反应的研究

本文报道了布朗斯特酸性离子液体1,3-二羧甲基咪唑对甲苯磺酸盐作为一种绿色、环境友好的催化剂,成功地催化Biginelli三组分反应合成了一系列3,4-二氢嘧啶-2(1H)-酮或硫酮化合物。该方法具有条件温和、产率高、反应时间短的优点。此外,催化剂离子液体可循环使用五次且催化活性没有明显降低。

Intermolecular cyclocondensation reaction of 3,4-dihydropyrimidine-2-thione under the Mitsunobu reaction conditions

A self-intermolecular cyclocondensation reaction of 3,4-dihydropyrimidine-2-thione（DHPM） to give a novel tricyclic structure containing DHPM core in the presence of diethyl azodicarboxylate（DEAD） and triphenylphosphine（TPP） at room temperature is reported.

Melamine trisulfonic acid:A new,efficient and recyclable catalyst for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones/thiones in the absence of solvent

Melamine trisulfonic acid（MTSA） can be used as an efficient and recyclable catalyst for the promotion of the synthesis of 3,4- dihydropyrimidin-2（1H）-ones/thiones（DHPMs） in the absence of solvent.All reactions were performed at 80℃in good to high yields.

Silica-bonded N-propyl sulfamic acid as an efficient recyclable catalyst for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones/thiones under heterogeneous conditions

Silica-bonded N-propyl sulfamic acid （SBNPSA） catalyzed one-pot three component Biginelli condensation of different substituted aromatic aldehydes with ethyl acetoacetate and urea/thoiurea to the respective 3,4-dihydropyrimidin-2-（lH）-ones and thiones in environment friendly procedure is described. The facile reaction conditions, simple isolation and purification procedures of this method make it a good option for the svnthesis of dihydropyrimidinones.

An efficient synthesis of novel benzo[b]pyrido[3',2':4,5]thieno[2,3-e][1,6]naphthy-ridine-8-ones

An efficient method for the synthesis of novel benzo[b]pyrido[3＇,2＇：4,5]thieno[2,3-e][l,6]naphthyridine-8-one derivatives has been developed using a Pictet-Spengler reaction between 4-（3-aminothieno[2,3-b]pyridin-2-yl）quinoline-2-ones,which could be obtained from the alkylation of4-bromomethylquinoline-2-ones with 3-cyanopyridine-2-thione followed by a Thorpe-Ziegler isomerization,and aromatic aldehydes under p-TsOH as catalysis in good yields.

An efficient synthesis of novel pyridothieno-fused thiazolo[3,2-α]pyrimidinones via Pictet–Spengler reaction

An efficient method for the synthesis of novel pyrido[3＇＇,2＇＇：4＇,5＇]thieno[3＇,2＇：2,3]pyrido [4,5：d][1,3]thiazolo[3,2-a]pyrimidine-4-one derivatives（5） has been developed using a Pictet–Spengler reaction between 2-（3-aminothieno[2,3-b]pyridin-2-yl）thiazolo[3,2-a] pyrimidin-5-one（3）, which could be obtained from the condensation of 7-（chloromethyl）-5H-thiazolo[3,2-a]pyrimidin-5-one（1） with3-cyanopyridine-2-thione（2） via Thorpe–Ziegler isomerization, and aromatic aldehydes under NH2SO3 H as catalysis in good yields.

N-Sulfonic acid poly(4-vinylpyridinium) chloride as a highly efficient and reusable catalyst for the Biginelli reaction

A mild, simple and efficient procedure for the preparation of 3,4-dihydropyrimidin-2（1H）-ones and -thiones is described using N-sulfonic acid poly（4-vinylpyridinium） chloride （NSPVPC） as a heterogeneous and efficient catalyst under solvent-free conditions. Simple methodologies, easy work-up procedure, easy preparation of the catalyst, excellent yields and very short reaction times are among the other advantages of this work. Further, the catalyst can be reused and recovered for several times without significant decrease in its activity.