3-(Diethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one(DEPBT) condensation developed by our group is an effective organophosphorus condensation reagent for the synthesis of protected peptides containing Tyr,Ser and Th...3-(Diethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one(DEPBT) condensation developed by our group is an effective organophosphorus condensation reagent for the synthesis of protected peptides containing Tyr,Ser and Thr with unprotected hydroxyl group on their side chain.Thus,DEPBT is useful for the synthesis of peptide alcohols,which have attracted much attention not only as the ligands but also as the enzyme inhibitors.A side reaction of DEPBT was found in the synthesis of Boc-β-Ala-HisOMe with unprotected imidazolyl group.In this paper,the discovery of this side reaction and the confirmation of the structure of this side product were reported.In addition,the influence of different reaction conditions on the side reaction were studied.Imidazolyl group was a key factor to cause the side reaction,excess DEPBT and high reaction temperature promoted the side reaction.展开更多
3,4-Dihydropyrimidin-2-(1H)-ones were synthesized in high yields by a one-pot cyclocondensation of aldehyde,1,3-dicarbonyl compound,and urea or thiourea using copper o-toluenesulfonate as a catalyst under solvent-free...3,4-Dihydropyrimidin-2-(1H)-ones were synthesized in high yields by a one-pot cyclocondensation of aldehyde,1,3-dicarbonyl compound,and urea or thiourea using copper o-toluenesulfonate as a catalyst under solvent-free conditions at 90℃.Effects of molar ratio of reactants,amount of catalyst,and reaction temperature on the yields of 3,4-dihydropyrimidin-2-(1H)-ones were investigated.The results showed that at the condition of naldehyde∶n1,3-dicarbonyl compounds∶nurea(or thiourea)=1∶1.2∶1.5,1 mol% catalyst(molar percent of aldehyde),2.0 h at 90℃,the yields of products were 51-96%.After reaction,the catalyst could be reused for four times without distinct loss of catalytic activity.展开更多
Four pyridazinone gluosodes 4 were synthesized by Koenig′s Knorr reaction of 6 (4 halophenyl) 3( 2H ) pyridazinone silver salt 2 with bromoacetylglucose 3.Treatment of 4 with dry ammonia at 0～-5℃ effected a removal...Four pyridazinone gluosodes 4 were synthesized by Koenig′s Knorr reaction of 6 (4 halophenyl) 3( 2H ) pyridazinone silver salt 2 with bromoacetylglucose 3.Treatment of 4 with dry ammonia at 0～-5℃ effected a removal of the acetyl protecting groups to yield compounds 5.When the substituent on the benaene ring was F or Cl ,O glucoside was synthesized principally.However,when the substituent was Br or I ,N glucoside was mainly obtained.Their structures were confirmed by 1H NMR,IR and elemental analysis.展开更多
文摘3-(Diethoxyphosphoryloxy)-1,2,3-benzotriazin-4(3H)-one(DEPBT) condensation developed by our group is an effective organophosphorus condensation reagent for the synthesis of protected peptides containing Tyr,Ser and Thr with unprotected hydroxyl group on their side chain.Thus,DEPBT is useful for the synthesis of peptide alcohols,which have attracted much attention not only as the ligands but also as the enzyme inhibitors.A side reaction of DEPBT was found in the synthesis of Boc-β-Ala-HisOMe with unprotected imidazolyl group.In this paper,the discovery of this side reaction and the confirmation of the structure of this side product were reported.In addition,the influence of different reaction conditions on the side reaction were studied.Imidazolyl group was a key factor to cause the side reaction,excess DEPBT and high reaction temperature promoted the side reaction.
文摘3,4-Dihydropyrimidin-2-(1H)-ones were synthesized in high yields by a one-pot cyclocondensation of aldehyde,1,3-dicarbonyl compound,and urea or thiourea using copper o-toluenesulfonate as a catalyst under solvent-free conditions at 90℃.Effects of molar ratio of reactants,amount of catalyst,and reaction temperature on the yields of 3,4-dihydropyrimidin-2-(1H)-ones were investigated.The results showed that at the condition of naldehyde∶n1,3-dicarbonyl compounds∶nurea(or thiourea)=1∶1.2∶1.5,1 mol% catalyst(molar percent of aldehyde),2.0 h at 90℃,the yields of products were 51-96%.After reaction,the catalyst could be reused for four times without distinct loss of catalytic activity.
文摘Four pyridazinone gluosodes 4 were synthesized by Koenig′s Knorr reaction of 6 (4 halophenyl) 3( 2H ) pyridazinone silver salt 2 with bromoacetylglucose 3.Treatment of 4 with dry ammonia at 0～-5℃ effected a removal of the acetyl protecting groups to yield compounds 5.When the substituent on the benaene ring was F or Cl ,O glucoside was synthesized principally.However,when the substituent was Br or I ,N glucoside was mainly obtained.Their structures were confirmed by 1H NMR,IR and elemental analysis.
