The identification of the ~1H spin system for the S-sulfonated insulin B chain was reported in a previous paper. In this note, the ~1H spin system for the S-sulfonated insulin A chain is reported based upon an absolut...The identification of the ~1H spin system for the S-sulfonated insulin B chain was reported in a previous paper. In this note, the ~1H spin system for the S-sulfonated insulin A chain is reported based upon an absolute value mode of a two dimensional correlation spectrum (2D-COSY), a phase sensitive double quantum spectrum (DQ), RELAYED-COSY (RCT) and a nuclear Overhauser 2D spectrum (NOESY).展开更多
Resonance assignments of the ~1H spectrum of insulin are the basis on which to investi-gate its solution conformation by using NMR method. Owing to the complicated aggregationbehaviour of the molecule to give broadene...Resonance assignments of the ~1H spectrum of insulin are the basis on which to investi-gate its solution conformation by using NMR method. Owing to the complicated aggregationbehaviour of the molecule to give broadened n. m. r. lines, only limited resonance assignmentshave been reported. S-sulfonated A and B chains of insulin gave ~1H spectra with good reso-lutions. Based on the 500 MHz absolute 2D-COSY spectrum and 400 MHz phase sensitiveDQF-COSY, Relayed-COSY and NOESY spectra of B chain recorded in D_2O, all of thespin system identifications of the non-labile protons in the S-sulfonated B chain of insulinwere reported including the specific resonance assignments of eight residues: B_3Asn, B_9Ser,B_(16)Tyr, B_(22)Arg, B_(26)Tyr, B_(27)Thr, B_(28)Pro and B_(29)Lys. The pK values of B_(16) and B_(26) tyrosineare 10.65 and 10.60 respectively from pH titration.展开更多
Silica-bonded S-sulfonic acid （SBSSA） was prepared by the reaction of 3-mercaptopropylsilica （MPS） and chlorosulfonic acid in chloroform. This solid acid has been employed as a recyclable catalyst for the synthesi...Silica-bonded S-sulfonic acid （SBSSA） was prepared by the reaction of 3-mercaptopropylsilica （MPS） and chlorosulfonic acid in chloroform. This solid acid has been employed as a recyclable catalyst for the synthesis of coumarins from phenols and β-keto- esters at 80 ℃ under solvent-free conditions.展开更多
A protocol for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and-thiones was developed by means of a three-component condensation of an aldehyde,a β-dicarbonyl compound,and urea or thiourea in acetic acid catalyze...A protocol for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and-thiones was developed by means of a three-component condensation of an aldehyde,a β-dicarbonyl compound,and urea or thiourea in acetic acid catalyzed by silica-bonded S-sulfonic acid.Compared to the classical Biginelli reaction conditions,this new protocol has the advantages of consistently excellent yields and short reaction times.After the reaction,the catalyst could be recovered easily and reused with little change in its activity.展开更多
2,3-Dihydroquinazolin-4（1H）-one derivatives were synthesized via a one-pot, three component reaction of isatoic anhydride and an aromatic aldehyde with ammonium acetate or primary amine catalyzed by silica-bonded S-...2,3-Dihydroquinazolin-4（1H）-one derivatives were synthesized via a one-pot, three component reaction of isatoic anhydride and an aromatic aldehyde with ammonium acetate or primary amine catalyzed by silica-bonded S-sulfonic acid in ethanol at 80 ℃. The reaction work-up is simple and the catalyst is easily separated from the products by filtration. The heterogeneous catalyst was recycled for ten runs upon the condensation reaction of isa- toic anhydride and 4-chlorobenzaldehyde with ammonium acetate without losing its catalytic activity.展开更多
基金Project supported by the National Natural Science Foundation of China, the National Institutes of Health of the U.S. and the British Royal Society.
文摘The identification of the ~1H spin system for the S-sulfonated insulin B chain was reported in a previous paper. In this note, the ~1H spin system for the S-sulfonated insulin A chain is reported based upon an absolute value mode of a two dimensional correlation spectrum (2D-COSY), a phase sensitive double quantum spectrum (DQ), RELAYED-COSY (RCT) and a nuclear Overhauser 2D spectrum (NOESY).
基金a grant (DK-34035) from the National Institutes of Health, U.S.A. and a grant (Biol-85-114) from the National Natural Science Foundation of China. The 500 MHz NMR measurements were taken in the National Institute for Medical Researc
文摘Resonance assignments of the ~1H spectrum of insulin are the basis on which to investi-gate its solution conformation by using NMR method. Owing to the complicated aggregationbehaviour of the molecule to give broadened n. m. r. lines, only limited resonance assignmentshave been reported. S-sulfonated A and B chains of insulin gave ~1H spectra with good reso-lutions. Based on the 500 MHz absolute 2D-COSY spectrum and 400 MHz phase sensitiveDQF-COSY, Relayed-COSY and NOESY spectra of B chain recorded in D_2O, all of thespin system identifications of the non-labile protons in the S-sulfonated B chain of insulinwere reported including the specific resonance assignments of eight residues: B_3Asn, B_9Ser,B_(16)Tyr, B_(22)Arg, B_(26)Tyr, B_(27)Thr, B_(28)Pro and B_(29)Lys. The pK values of B_(16) and B_(26) tyrosineare 10.65 and 10.60 respectively from pH titration.
文摘Silica-bonded S-sulfonic acid （SBSSA） was prepared by the reaction of 3-mercaptopropylsilica （MPS） and chlorosulfonic acid in chloroform. This solid acid has been employed as a recyclable catalyst for the synthesis of coumarins from phenols and β-keto- esters at 80 ℃ under solvent-free conditions.
基金supported by the Research Council of Payame Noor University
文摘A protocol for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and-thiones was developed by means of a three-component condensation of an aldehyde,a β-dicarbonyl compound,and urea or thiourea in acetic acid catalyzed by silica-bonded S-sulfonic acid.Compared to the classical Biginelli reaction conditions,this new protocol has the advantages of consistently excellent yields and short reaction times.After the reaction,the catalyst could be recovered easily and reused with little change in its activity.
文摘2,3-Dihydroquinazolin-4（1H）-one derivatives were synthesized via a one-pot, three component reaction of isatoic anhydride and an aromatic aldehyde with ammonium acetate or primary amine catalyzed by silica-bonded S-sulfonic acid in ethanol at 80 ℃. The reaction work-up is simple and the catalyst is easily separated from the products by filtration. The heterogeneous catalyst was recycled for ten runs upon the condensation reaction of isa- toic anhydride and 4-chlorobenzaldehyde with ammonium acetate without losing its catalytic activity.
