A rapid and simple procedure for synthesis of 2,6-di（naphthalene thioureido carbamino）pyridine fluorescine anion acceptor by the reaction between pyridine-2,6-dicarbohydrazide obtained from 2,6-dimethylpyridine afte...A rapid and simple procedure for synthesis of 2,6-di（naphthalene thioureido carbamino）pyridine fluorescine anion acceptor by the reaction between pyridine-2,6-dicarbohydrazide obtained from 2,6-dimethylpyridine after three-step reaction and 1-napbthyl isothiocyanate is described, and all reactions could be carried out under microwave heating condition.展开更多
Consuming a cyanogenic plant is an etiological factor to the persistence of iodine deficiency in the post salt iodization phase. Ghana, notably the Northern belt, still reports of iodine deficiency after 14 years of m...Consuming a cyanogenic plant is an etiological factor to the persistence of iodine deficiency in the post salt iodization phase. Ghana, notably the Northern belt, still reports of iodine deficiency after 14 years of mandatory consumption of iodized salt by an Act of Parliament. The study aimed at determining the cyanide contents of leaves of commonly consumed cassava varieties in Ghana and investigating the effects of some environmental factors on cyanide content. Three communities each from Southern, Middle and Northern Ghana served as the study sites from where young, non-diseased and fully-spread cassava leaves were sampled from plants of commonly consumed cassava varieties. Cyanide was analyzed by the standard color^metric method based on the chloramine-T/pyridine-barbituric acid protocol （4500-CN E）. Cassava leaves from Northern Ghana had significantly higher mean cyanide content （177.22 ± 20.82 ppm） than those from Middle （130.83± 33.00 ppm） and Southern Ghana （127.24 ± 37.54 ppm） （P 〈 0.001）. Two-factor ANOVA showed significantly higher adverse environmental effects on cyanide contents of leaves of unimproved cassava varieties than improved ones （R2 = 0.627, P = 0.023）. From multiple regression analysis, temperature was the most significant environmental factor explaining 33% of the variability in cyanide content （R2 = 0.331, P = 0.002）, followed by altitude （R2 = 0.106, P = 0.049） and rainfall （R2 = 0.084, P = 0.062）. The high cyanide contents of cassava leaves from Northern Ghana, due principally to the high atmospheric temperature, may be a contributory factor to the high prevalence of goiter and the persistence of iodine deficiency in that geographic region.展开更多
The Ni(Ⅱ)-chiral(4S,4'S)-2,2'-(4,6-dibenzofurandiyl)bis[4,5-dihydro-4-phenyloxazole](DBFOX/Ph)-catalyzed asymmetric 1,3-dipolar cycloadditions of nitrile imines to N-α,β-unsaturated acylpyrazoles was presen...The Ni(Ⅱ)-chiral(4S,4'S)-2,2'-(4,6-dibenzofurandiyl)bis[4,5-dihydro-4-phenyloxazole](DBFOX/Ph)-catalyzed asymmetric 1,3-dipolar cycloadditions of nitrile imines to N-α,β-unsaturated acylpyrazoles was presented.This tactic rendered a facile and feasible route to prepare the optically active tetrasubstituted 5-3,5-dimethylpyrazole acyl dihydropyrazole cy-cloadducts bearing one or two contiguous stereocenters in good yields(up to 97%yield)with high regioselectivities(100%)and enantioselectivities(up to 97.5%ee).Following that,chiral cycloadducts could be obtained consistently in good chemical yields with excellent enantioselectivities within the gram scale process,additionally,toward five kinds of derivatization reac-tions like nucleophilic and reduction for further conversion of chiral cycloadducts to related chiral dihydropyrazole derivatives encompassing different substituents.展开更多
As important constitutes in many drugs, piperazine comprised compounds are of great interest for drug design. In this paper, two piperazine-based compounds were synthesized for the first time, with different strategie...As important constitutes in many drugs, piperazine comprised compounds are of great interest for drug design. In this paper, two piperazine-based compounds were synthesized for the first time, with different strategies exploited. For one compound, a highly reactive intermediate of isothiocyanate was constructed to get the desired piperazinecarbothioamide. The synthesis of the other compound was completed sequentially through Friedel-Crafts acylation, coupling reaction and Michael addition. Both synthetic routes have short steps and acceptable yields, and such strategies can be applied to the synthesis of similar oioerazine-containin~ comoounds.展开更多
文摘A rapid and simple procedure for synthesis of 2,6-di（naphthalene thioureido carbamino）pyridine fluorescine anion acceptor by the reaction between pyridine-2,6-dicarbohydrazide obtained from 2,6-dimethylpyridine after three-step reaction and 1-napbthyl isothiocyanate is described, and all reactions could be carried out under microwave heating condition.
文摘Consuming a cyanogenic plant is an etiological factor to the persistence of iodine deficiency in the post salt iodization phase. Ghana, notably the Northern belt, still reports of iodine deficiency after 14 years of mandatory consumption of iodized salt by an Act of Parliament. The study aimed at determining the cyanide contents of leaves of commonly consumed cassava varieties in Ghana and investigating the effects of some environmental factors on cyanide content. Three communities each from Southern, Middle and Northern Ghana served as the study sites from where young, non-diseased and fully-spread cassava leaves were sampled from plants of commonly consumed cassava varieties. Cyanide was analyzed by the standard color^metric method based on the chloramine-T/pyridine-barbituric acid protocol （4500-CN E）. Cassava leaves from Northern Ghana had significantly higher mean cyanide content （177.22 ± 20.82 ppm） than those from Middle （130.83± 33.00 ppm） and Southern Ghana （127.24 ± 37.54 ppm） （P 〈 0.001）. Two-factor ANOVA showed significantly higher adverse environmental effects on cyanide contents of leaves of unimproved cassava varieties than improved ones （R2 = 0.627, P = 0.023）. From multiple regression analysis, temperature was the most significant environmental factor explaining 33% of the variability in cyanide content （R2 = 0.331, P = 0.002）, followed by altitude （R2 = 0.106, P = 0.049） and rainfall （R2 = 0.084, P = 0.062）. The high cyanide contents of cassava leaves from Northern Ghana, due principally to the high atmospheric temperature, may be a contributory factor to the high prevalence of goiter and the persistence of iodine deficiency in that geographic region.
基金Project supported by the National Natural Science Foundation of China(Nos.22278098,21908034,22008045)the Natural Science Foundation of Heilongjiang Province(Nos.LH2021H001,LH2023B013)。
文摘The Ni(Ⅱ)-chiral(4S,4'S)-2,2'-(4,6-dibenzofurandiyl)bis[4,5-dihydro-4-phenyloxazole](DBFOX/Ph)-catalyzed asymmetric 1,3-dipolar cycloadditions of nitrile imines to N-α,β-unsaturated acylpyrazoles was presented.This tactic rendered a facile and feasible route to prepare the optically active tetrasubstituted 5-3,5-dimethylpyrazole acyl dihydropyrazole cy-cloadducts bearing one or two contiguous stereocenters in good yields(up to 97%yield)with high regioselectivities(100%)and enantioselectivities(up to 97.5%ee).Following that,chiral cycloadducts could be obtained consistently in good chemical yields with excellent enantioselectivities within the gram scale process,additionally,toward five kinds of derivatization reac-tions like nucleophilic and reduction for further conversion of chiral cycloadducts to related chiral dihydropyrazole derivatives encompassing different substituents.
基金National Basic Research Program of China(Grant No.2012CB518000)the National Natural Science Foundation of China(Grant No.21172012)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120001110010)
文摘As important constitutes in many drugs, piperazine comprised compounds are of great interest for drug design. In this paper, two piperazine-based compounds were synthesized for the first time, with different strategies exploited. For one compound, a highly reactive intermediate of isothiocyanate was constructed to get the desired piperazinecarbothioamide. The synthesis of the other compound was completed sequentially through Friedel-Crafts acylation, coupling reaction and Michael addition. Both synthetic routes have short steps and acceptable yields, and such strategies can be applied to the synthesis of similar oioerazine-containin~ comoounds.
