Catalyst Free Synthesis of Pyridine-2,6-bis(2-bromo-propane-1,3-dione) and Pyrdine-2,6-bis(<i>N</i>-arylthiazoline-2-thiones)

We have described herein a catalyst-free preparation method of pyridine-2,6-bis(N-alkylthiazoline-2-thiones) (4a-i) by the reaction of primary amines, CS2, and pyridine-2,6-bis(2-bromo-1,3- dicarbonyl) derivatives (2a-c) in water. Also, we have described a catalyst free, green chemistry protocols to monobromination of pyridine-2,6-bis(2-bromo-1,3-dicarbonyl) derivatives with high yield, using NBS as a brominating agent, that led to eco-friendly isolation and purification proce-dures. Furthermore, we have studied the reactivity of pyridine-2,6-bis(2-bromo-1-methyl-pro- pane-1,3-dione) (2a) towards thiourea to afford 2,6-bis(5-benzoyl-2-aminothiazol-4-yl)pyridine (9).

Synthesis and Crystal Structure of Dichlorobis-(1-methylimidazoline-2(3H)-thione-S) Cobalt(II)

The reaction of anhydrous cobalt(II) dichloride with 1-methylimidazoline-2(3H)- thione in dichloromethane solution gave the title complex, [Co(C4H6N2S)2Cl2]. X-ray single-crystal analysis revealed that the complex crystallizes in a monoclinic system, space group P21/c, a = 13.9707(10), b = 10.0435(7), c = 10.3910(6) ?, β = 91.181(3)o, V = 1457.70(17) ?3, Z = 4, C8H12Cl2N4S2Co, Mr = 358.17, Dc = 1.632 g/cm3, μ = 1.813 mm–1, F(000) = 724, the final R = 0.0710 and wR = 0.1224 for 1549 observed reflections with I > 2σ(I). The Co atom is coordinated by two S atoms from two 1-methylimidazoline-2(3H)-thione ligands and two chloride ions in a slightly distorted tetrahedral geometry. The intramolecular classical hydrogen-bonding interactions involving chloride ions and N–H groups of the heterocyclic thione ligands are observed. The offset π-π stacking interactions between the imidazole rings of adjacent molecules with a face-to-face dis- tance of 3.604 ? are found in the packing diagram.

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 Dinuclear Zinc(II) Complex with 3-Me-N-oxopyridine-2-thiol

The complex Zn(Mept) 2 (Mept=Bis(3-methyl-oxopyridine-2-thionato)) was obtained by the reaction of MeHpt with ZnSO 4 in ethanol. A single crystal X-ray study shows that the complex bis(3-Me-oxopyridine-2-thionato)zinc(II) (Zn 2C 24 H 24 N 4O 4S 4) is a dimer. The oxygen and sulfur atoms from Mept ligand coordinates to a zinc atom forming (3-Me-oxopyridine-2-thionato)zinc(II) monomer, and every two monomeric units are linked centrosymmetrically by two oxygen bridges. The compound Zn(Mept) 2 belongs to the monoclinic system with space group P2 1/c, a=7.7627(9), b = 10.3335(7), c=17.4528(13) , β=99.134(9)°, V=1382.2(2) 3, Z=2, M r=691.46, D c=1.661 g/cm 3, μ=2.076 mm -1 , F(000)=704, R=0\^0463, R w=0.0747 for 3378 reflections with I>2σ(I). The coordination geometry about each Zn(II) ion is a distorted trigonal bipyramid. The Zn atom is coordinated by two sulfur atoms (Zn(1)-S(1) 2.307(1); Zn(1)-S(2) 2.295(2)) and one oxygen atom (Zn-O(2A) 2.126(3)) in the equatorial plane, while the two oxygen atoms of Mept ligands (Zn(1)-O(1) 2\^050(3), Zn(1)-O(2) 2\^172(3)) occupy the axial positions with O(1)-Zn(1)-O(2) 177\^2(1)°.

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.

Synthesis, Spectroscopic Characterization and Antimicrobial Activity of Some New 2-Substituted Imidazole Derivatives

The reaction of imidazole-2-thione derivative 1 with 2-chloro-N-p-tolylacetamide afforded the corresponding 2-(1HI-imidazol-2-ylthio)-N-p-tolylacetamide 2. Reaction compound 2 with different reagents such as p-chlorobenzaldehyde and p-chlorophenyl diazonium chloride afforded the corresponding arylidene derivative 3 and hydrazone derivative 6. Reactions of 2 with carbon disulfide in dimethylformamide (DMF) in one equivalent potassium hydroxide afforded intermediate potassium sulphide salt 8, which treatment with dilute hydrochloric acid and phenacyl bromide afforded the corresponding 2-[p-tolylcarbamoyl]ethanedithioic acid 9 and 3-[benzo-ylmethylthio]-N-p-tolyl-3-thioxo-propaneamide 10. While the reaction 2 with carbon disulphide in the presence of two equivalent potassium hydroxide in DMF gave non-isolated potassium salt 11, which was allowed to react with halogenated compounds namely ethyl chloroacetate and methyl iodide afforded the corresponding 3, 3-bis[(ethoxycarbonyl)methylthio]-N-p-tolylacrylamide 12 and 3,3-bis-(methylthio)-N-p-tolylacrylamide 13 respectively. Reaction 2 with phenyl isothiocyanate in basic DMF yielded the intermediate potassium sulphide salt 18. Acidification 18 with dilute hydro-chloric acid afforded the corresponding thiocarbamoyl derivative 19. Treatment of intermediate 18 with methyl iodide, phenacyl bromide and ethylchloroacetate afforded the 3-anilino-3-(methylthio)-N-p-tolylacrylamide 20, 2-(1,3-thiazol-2(3H)-ylidene)-N-p-tolylacetamide 21 and 2-(4-oxo-3-phenyl-1,3-thiazolidin-2-ylidene)-N-p-tolylacetamide 22 respectively. The structure of the newly synthesized compounds has been confirmed by elemental analysis and spectra data. Synthesized compounds 2, 3, 6, 13, 15a, 15b, 17, 20, 21, 22 and 23 were screened for their antibacterial activities in vitro against Gram-positive (Staphylococcus aureus and Bacillus subtilis), Gram-negative (Pseudomonas aeuroginosa and Escherichia coli ) and antifungal activities against (Aspergillus fumigates, Syncephalastrum racemosum, Geotrichum candidum and Candida albicans).

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.

Novel 1,3,5-thiadiazine-2-thione derivatives containing a hydrazide moiety:Design, synthesis and bioactive evaluation against phytopathogenic fungi in vitro and in vivo

A series of novel 1,3,5-thiadiazine-2-thione derivatives bearing a hydrazide moiety were designed, synthesized and evaluated for their antifungal activities against Rhizoctonia solani (Rs), Fusarium graminearum (Fg), Botrytis cinerea (Bc) and Colletotrichum capsici (Cc). The in vitro antifungal bioassays indicated that most of title compounds displayed good selectivity and specificity aganist Rs relative to Fg, Bc and Cc. Strikingly, the title compound N'-(4-chlorophenyl)-2-(5-phenyl-6-thioxo-1,3,5-thiadiazinan-3-yl)acethydrazide (5b) obviously inhibited the Rs growth in vitro with the EC50 value of 0.24μg/mL, which is approximately 2-folds more effective than the commercialized fungicide carbendazim (0.55 μg/mL). The in vivo anti-Rs effects of title compound 5b were further evaluated on rice leaves with control efficacies of 98.58% at 200 μg/mL and 61.27% at 100 μg/mL. The above researches provide a significant reference for the further structural optimization of 1,3,5-thiadiazine-2-thione derivatives bearing a hydrazide moiety as potential fungicides.

Diastereoselective Synthesis of Functionalized Tetrahydropyrimidin-2-thiones via ZnCl2 Promoted One-pot Reactions

In the presence of zinc chloride,the in situ generatedβ-enamino ester from the reaction of morpholine,piperidine and pyrrolidine with methyl propiolate reacted,with aromatic aldehydes and thiourea in ethanol resulting in the functionalized tetrahydropyrimidin-2-thiones in satisfactory yields and with good diastereoselectivity.When aromatic aldehydes bearing electron-withdrawing group were used in the reaction,the 4-hydroxytetrahydropyrimidin-2-thione derivatives were obtained as the main product.

Synthesis of 1-Benzoyl-3-aryl-4-hydroxy-4-phenylimidazolidin-2-thiones

1-Benzoyl-3-aryl-4-hydroxy-4-phenylimidazolidin-2-thiones can be synthesized readily from the cyclization of 1-benzoyl-3-arylthioureas with bromine-acetophenone in the presence of excess triethylamine.

An Efficient Synthesis of [1,2,4]Triazolo[3,2-d][1,5]benzoxazepin-2-thiones, a Kind of Novel Tricyclic O,N-Heterocycles

A series of novel tricyclic O,N-heterocycles, [1,2,4]triazolo[3,2-d][1,5]benzoxazepin-2-thiones 7 were achieved via acid-induced ring closure of the geminal arylazo isothiocyanate compounds 5 which were derived from substituted chroman-4-ones, followed by feasible ring expansion with simultaneous insertion of the nitrogen atom into the carbon skeleton. The X-ray crystal structure of 7d was also described.

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.

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.

Microwave-assisted 6π-electrocyclization in water

The recent development of microwave-assisted aqueous synthesis of polyheterocyclic-fused quinoline-2-thiones through 6π-electrocyclization was highlighted.