The synthesis of cyanamides and tetrazoles from isothiocyanates through tandem reaction using cobalt catalyst has been demonstrated. In the case of tetrazole preparation, the reaction involved addition/desulfurization/nucleophilic addition/electrocyclization, whereas aromatic cyanamides were constructed from isothiocyanates through addition/desulfurization. Cheap cobalt sulfate was used for the synthesis
versatile synthetic methodology for the construction of tetrazoles and guanidines in the presence of an eco-friendly, inexpensive, easily available iron reagent. Aromatic thioureas with electron-donating substituents produced their respective target products in quantitative yield. In contrast, when electron-withdrawing substituted aromatic thioureas were used, the expected products were obtained in reduced
The iron-mediated efficient multi-component method has been demonstrated for the synthesis of substituted cyanamides from isothiocyanates under mild reaction conditions. Subsequent nucleophilic addition and desulfurization are involved in this proposed synthetic methodology. All the reactions are rapid, facile, and accomplished at room temperature. A variety of substrates readily underwent the optimized
The invention relates to compounds of formula
wherein R
1
, R
2
, R
3
, R
4
, X and Y are as defined herein and to pharmaceutically active acid addition salts thereof.
The compounds can be used for the treatment of Alzheimer's disease, cerebral amyloid angiopathy, hereditary cerebral hemorrhage with amyloidosis, Dutch-type (HCHWA-D), multi-infarct dementia, dementia pugilistica or Down syndrome.
A Simple and Convenient Synthesis of Isolated Fused Heterocycles Based on: 6-Phenyl-2-thioxo-2,3-dihydropyrimidin-4(5H)-one and 5-Acetyl-6-phenyl-2-thioxo-2,3-dihydropyrimidin-4(5H)-one
作者:Mohamed Ahmed Mahmoud Abdel Reheim、Ibrahim Saad Abdel Hafiz、Mohamed Ahmed Elian
DOI:10.3987/com-16-13467
日期:——
The reaction of 6-phenyl-2-thioxo-2,3-dihydropyrimidin-4(5H)-one 1 with acetyl chloride in acetic anhydride in the presence of sodium acetate afforded 5-acetyl-6-phenyl-2-thioxo-2,3-dihydropyrimidin-4(5H)-one 2 which reacted with bromine, hydrazine hydrate, phenylhydrazine, cyanothioacetamide, aldehydes and (malononitrile/sulfur) to give 2-thioxo-2,3-dihydropyrimidine derivatives 4, 7a,b, 8, 10 and 11 respectively. In the present investigation 6-phenyl-2-thioxo-2,3-dihydropyrimidin-4(5H)-one 1 was reacted with chloroacetyl chloride to yield the corresponding compound 13. Compound 1 was reacted with some electrophilic reagents such as (benzylidene-cyanothioacetamide derivatives, 2-cyano-2-cyclopentylethanethioamide, 2-cyano-2-cyclohexyl-ethanethioamide and aromatic diazonium salts) to give compounds 23, 27a,b and 35 respectively. The newly synthesized heterocycles were characterized on the basis of their chemical properties and spectral data.