Synthesis and Crystal Structure of 3-Benzyl-5-cyclohexylamino-6-phenyl-3,6-dihydro-1,2,3-triazolo[4,5-d]pyrimidin-7-one

The title compound 3-benzyl-5-cyclohexylamino-6-phenyl-3,6-dihydro-1,2,3- triazolo[4,5-d]pyrimidin-7-one (C23H24N6O, Mr = 400.48) has been synthesized by means of tandem aza-Wittig reaction, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 6.5550(6), b = 10.3711(10), c = 31.265(3) ?, β = 93.827(2)o,V = 2120.8(4) ?3, Z = 4, Dc = 1.254 g/cm3, S = 1.025, μ(MoKa) = 0.081 mm-1, F(000) = 848, R = 0.0576 and wR = 0.1368. X-ray analysis reveals that all ring atoms in the triazolopyrimidinone moiety are almost coplanar and the cyclohexyl ring adopts a chair confor- mation.

7-Deazapurines:Synthesis of new pyrrolo[2,3d]pyrimidin-4-onescatalyzed by a Brφnsted-acidic ionic liquid as a green and reusable catalyst

Some new 2-aryl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-ones have been prepared through cyclocondensation of 2-amino 1H-pyrrole-3-carboxamides with aromatic aldehydes followed by air oxidation in the presence of 3-methyl-1-（4-sulfonic acid）butylimidazolium hydrogen sulfate[（CH;）;SO;HMIM][HSO;],a Br（?）nsted-acidic ionic liquid,as a green and reusable catalyst in solvent-free conditions.

Synthesis and Crystal Structure of 1-(4-Fluorophenyl)-2-hexylthiobenzo[4,5]-furo[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidin-5(1H)-one

The crystal structure of the title compound 1-（4-fluorophenyl） -2-hexylthio-benzo [4,5]furo[3,2-d]-1,2,4-triazolo[1,5-a]pyrimidin-5（1H） -one（C23H21FN4O2S,Mr = 436.5） has been prepared and determined by single-crystal X-ray diffraction. The crystal is of monoclinic,space group P21/n with a = 13.9854（3） ,b = 17.2678（4） ,c = 18.1828（5）A,β = 99.364（2） °,V = 4332.58（18） A^3,Z = 4,Dc = 1.338,F（000） =1824,μ = 0.185 mm^-1,MoKa radiation（λ = 0.71073） ,R = 0.0538 and wR = 0.1162 for 4728 observed reflections with I 〉 2σ（I） . X-ray diffraction analysis reveals the fused rings of benzo[4,5]furo[3,2-d]-1,2,4-triazolo[1,5-a] pyrimidin-5（1H） -one system are nearly coplanar. The crystal packing is mainly stabilized by weak intermolecular C-H···O hydrogen bond and π-π interactions.

Syntheses and Vasodilatory Activities of New Pyrazolo[4,3-d]pyrimidin-7-ones

A series of novel pyrazolo [ 4,3-d ] pyrimidin-7-ones was designed and synthesized in order to find new potent phosphodiesterase 5 inhibitors（PDE5）. The structures of all the compounds were confirmed by IR, ^1H NMR and MS; their in vitro vasodilatory activities were tested on isolated rabbit aortic spiral strips. Among them, compound X3 displays a significant vasodilatory activity, which is more potent than verapamil.

A rapid synthesis of isoxazolo[5,4-d]pyrimidin-4(5H)-ones under microwave irradiation with solid acid catalysis in solvent-free conditions

A rapid and efficient method for the synthesis of isoxazolo[5,4-d]pyrimidin-4（5H）-ones has been developed through cyclocondensation of 5-aminoisoxazole-4-carboxamides with orthoesters under conventional heating and solvent-free microwave irradiation with solid acid catalysis. In comparison, the reactions are faster and the yields are higher under microwave irradiation.

Synthesis and Bronchodilatory Activities of New Pyrazolo[4,3-d]pyrimidin-7-ones

Twelve novel pyrazolo [4,3-d] pyrimidin-7-ones were synthesized and their structures were confirmed by IR, 1H NMR and MS. Their in vitro bronchodilatory activities were tested in guinea-pigs. The pharmacological results show that compound 11c has more potent activity than aminophylline.

Synthesis and Crystal Structure of 2-Ethoxy-3-n-butyl-benzofuro [2,3-d]pyrimidin-4(3H)-one

The crystal structure of the new title compound 2-ethoxy-3-n-butyl- benzofuro[2,3d]pyrimidin-4（3H）-one （C16H18N2O3, Mr = 286.32） has been prepared and determined by singlecrystal X-ray diffraction. The crystal is of monoclinic, space group P21/c with a = 13.7167（14）, b = 13.113（1）, c = 8.378（1） A, β = 98.992（2）^o, V = 1488.4（3） A^3, Z = 4, Dc = 1.278, F（000） = 608, μ = 0.089 mm^-1, MoKa radiation （2 = 0.71073）, R = 0.0498, wR = 0.1238 for 2336 observed reflections with I 〉 2σ（I）. X-ray diffraction analysis reveals that all ring atoms in the benzo[4, 5]furo [2,3-d] pyrimi- dinone moieties are almost coplanar.

A Solution-Phase Parallel Synthesis of 5-Substituted 3,6-Dihydro-7H-1,2,3-triazolo[4,5-dJpyrimidin-7-ones

5-Substituted 7H-1,2,3-triazolo[4,5-d]pyrimidin-7-ones （4） were rapidly prepared by a solution-phase parallel synthetic method, which includes aza-Wittig reaction of iminophosphorane （1） with phenyl isocynate to give car- bodiimide （2） and subsequent reaction of 2 with various amine and alcohols in the presence of catalytic amount of sodium alkoxide in a parallel fashion.

New efficient synthesis of 2,5,6-trisubstituted oxazolo[5,4-d]pyrimidi-7(6H)-ones via an oxazolyliminophosphorane

A new efficient synthesis of 2,5,6-trisubstituted oxazolo（5,4-d]pyrimidi-7（6H）-ones by consecutive azaWittig reaction was developed.The sequential three-component reaction of oxazolyliminophosphorane4,isocyanates and amines produced 2,5,6-trisubstituted oxazolo[5,4-d]pyrimidi-7（6H）-ones 7 in good overall yields in the presence of catalytic amount of EtONa.

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.