A new practical method for the synthesis of unsymmetrical ureas was achieved by reaction of phenylurea with primary and secondary amines under neutral and mild condition in very good yields. The reaction took place in...A new practical method for the synthesis of unsymmetrical ureas was achieved by reaction of phenylurea with primary and secondary amines under neutral and mild condition in very good yields. The reaction took place in refluxing dioxane and does not require any catalyst or additives.展开更多
A series of 5-arylidene thiobarbituric acids were prepared from aromatic aldehydes and thiobarbituric acid in water without catalyst conditions in good yields. The structures were characterized by elemental analysis,...A series of 5-arylidene thiobarbituric acids were prepared from aromatic aldehydes and thiobarbituric acid in water without catalyst conditions in good yields. The structures were characterized by elemental analysis, IR and 1H NMR spectra.展开更多
A novel kinetic method for determination of uric acid in human serum by means of an uncatalyzed BZ system consisting of potassium bromate and p-hydroxybenzaldehyde （p-HBA） in sulfuric acid medium was proposed, in wh...A novel kinetic method for determination of uric acid in human serum by means of an uncatalyzed BZ system consisting of potassium bromate and p-hydroxybenzaldehyde （p-HBA） in sulfuric acid medium was proposed, in which the analyte perturbation to the system was recorded close to the bifurcation point. The potential change was directly proportional to the logarithm of concentration of uric acid in the range of 3.73 × 10 8--7.48 × 10-4 mol.L-1 （r=0.9983） with a detection limit of 7.45 × 10-9mol.L-I and a recovery from 98.9% to 101.1%. A comparison between the proposed technique and other methods indicated that results obtained were in agreement with those in clinical detection. In addition, the possible mechanism of action of uric acid on the uncatalyzed BZ reaction was also discussed briefly.展开更多
基金Financial support of this work from the Research Council of the University of Mazandaran is gratefully acknowledged
文摘A new practical method for the synthesis of unsymmetrical ureas was achieved by reaction of phenylurea with primary and secondary amines under neutral and mild condition in very good yields. The reaction took place in refluxing dioxane and does not require any catalyst or additives.
基金the Natural Science Foundation of Shaan’xi Province(No.2000H03)for support of this work.
文摘A series of 5-arylidene thiobarbituric acids were prepared from aromatic aldehydes and thiobarbituric acid in water without catalyst conditions in good yields. The structures were characterized by elemental analysis, IR and 1H NMR spectra.
基金This work was supported in part by the Project of International Cooperation between China and Ukraine （No. 043-05）, the National Natural Science Foundation of China （No. 20873101）, the Natural Science Foundation of Gansu （No. 1010RJZA015） and the project LKQN-08-9 of Northwest Normal University, China.
文摘A novel kinetic method for determination of uric acid in human serum by means of an uncatalyzed BZ system consisting of potassium bromate and p-hydroxybenzaldehyde （p-HBA） in sulfuric acid medium was proposed, in which the analyte perturbation to the system was recorded close to the bifurcation point. The potential change was directly proportional to the logarithm of concentration of uric acid in the range of 3.73 × 10 8--7.48 × 10-4 mol.L-1 （r=0.9983） with a detection limit of 7.45 × 10-9mol.L-I and a recovery from 98.9% to 101.1%. A comparison between the proposed technique and other methods indicated that results obtained were in agreement with those in clinical detection. In addition, the possible mechanism of action of uric acid on the uncatalyzed BZ reaction was also discussed briefly.
