The coaggregating tendencies of dodecane,hexadecane,dodecanol and hexadecanol have been investigated kinetically.It has been confirmed that organic molecules with a hydroxy-group possess smaller coaggregating tendenci...The coaggregating tendencies of dodecane,hexadecane,dodecanol and hexadecanol have been investigated kinetically.It has been confirmed that organic molecules with a hydroxy-group possess smaller coaggregating tendencies than similar molecules without the hydroxy-group.展开更多
Novel azine based receptors with phenolic hydroxyl groups have been synthesized and characterized. A remarkable color change was observed from 1H NMR and UV-Vis titrations upon the addition of fluoride ions to the sol...Novel azine based receptors with phenolic hydroxyl groups have been synthesized and characterized. A remarkable color change was observed from 1H NMR and UV-Vis titrations upon the addition of fluoride ions to the solution of receptors in DMSO. The addition of chloride, bromide and iodide to the receptors did not induce any change. The UV-Vis data indicate that a 1∶1 stoichiometry complex is formed between receptors and F-. 1H NMR titrations and solvation effect confirmed hydrogen interaction between the receptors and anion. Hence, the receptors bearing phenolic hydroxyl groups can act as fluoride ion sensors even in the presence of other hahide ions.展开更多
Novel receptors based on Schiff base bearing phenolic hydroxy groups have been synthesized and characterized.The UV-vis date indicates that a 1∶1 stoichiometry complex is formed between receptors and F-.1H NMR titrat...Novel receptors based on Schiff base bearing phenolic hydroxy groups have been synthesized and characterized.The UV-vis date indicates that a 1∶1 stoichiometry complex is formed between receptors and F-.1H NMR titrations and solvation effect confirmed hydrogen interaction between the receptors and anion.The results indicate that the affinity is related to the number of hydrogen bond.Hence,the receptors 1,2 and 3 can act as fluoride ion sensors even in the presence of other hahide ions.展开更多
The 2-hydroxy-4-methoxybenzyl(Hmb)backbone modification can prevent amide bond-mediated sidereactions(e.g.,aspartimide formation,peptide aggregation)by installing the removable Hmb group into a peptide bond,thus impro...The 2-hydroxy-4-methoxybenzyl(Hmb)backbone modification can prevent amide bond-mediated sidereactions(e.g.,aspartimide formation,peptide aggregation)by installing the removable Hmb group into a peptide bond,thus improving the synthesis of long and challenging peptides and proteins.However,its use is largely precluded by the limited Hmb’s installation sites.In this report,an improved installation of Hmb(iHmb)method was developed to achieve the flexible installation and the convenient removal of Hmb.The iHmb method involves two critical steps:(1)oxidative diazotization of the readily installed 2-hydroxy-4-methoxy-5-amino-benzyl(Hmab)to give 2-hydroxy-4-methoxy-5-diazonium-benzyl(Hmdab)by combining soamyl nitrite(IAN)/HBF_(4),and(2)reductive elimination of Hmdab to give the desired Hmb by 1,2-ethanedithiol(EDT).The iHmb method enables the installation of Hmb at any primary amino acid including the highly sterically hindered amino acids(e.g.,valine and isoleucine).The practicality and utility of the iHmb method was demonstrated by one-shot solid-phase synthesis of a challenging aspartimide-prone peptide,the mirror-image version of a hydrophobic peptide and a long-chain peptide up to 76-residue.Furthermore,the iHmb method can be utilized to facilitate chemical protein ligation,as exemplified by the synthesis of the single-spanning membrane protein sarcolipin.The iHmb method expands the toolkit for peptide synthesis and ligation and facilitates the preparation of peptides/proteins.展开更多
Azo-salicylaldehyde Schiff base-typed receptors containing an acidic H-bond donor moiety were syn-thesized and characterized. The UV-Vis data indicate that these receptors could act as selective col-orimetric sensors ...Azo-salicylaldehyde Schiff base-typed receptors containing an acidic H-bond donor moiety were syn-thesized and characterized. The UV-Vis data indicate that these receptors could act as selective col-orimetric sensors for basic anions and acidic species hydrogen sulfate by different color changes in a water-containing medium. The experiment of Brφnsted acid-base reaction by adding the sodium hy-droxide or perchloric acid revealed that the mechanism of recognition of anions might be deprotona-tion/protonation of the OH fragments by interacting with different anions and that the deprotona-tion/protonation process is fully reversible. The deprotonation/protonation of the receptors is respon-sible for the dramatic color change.展开更多
文摘The coaggregating tendencies of dodecane,hexadecane,dodecanol and hexadecanol have been investigated kinetically.It has been confirmed that organic molecules with a hydroxy-group possess smaller coaggregating tendencies than similar molecules without the hydroxy-group.
文摘Novel azine based receptors with phenolic hydroxyl groups have been synthesized and characterized. A remarkable color change was observed from 1H NMR and UV-Vis titrations upon the addition of fluoride ions to the solution of receptors in DMSO. The addition of chloride, bromide and iodide to the receptors did not induce any change. The UV-Vis data indicate that a 1∶1 stoichiometry complex is formed between receptors and F-. 1H NMR titrations and solvation effect confirmed hydrogen interaction between the receptors and anion. Hence, the receptors bearing phenolic hydroxyl groups can act as fluoride ion sensors even in the presence of other hahide ions.
文摘Novel receptors based on Schiff base bearing phenolic hydroxy groups have been synthesized and characterized.The UV-vis date indicates that a 1∶1 stoichiometry complex is formed between receptors and F-.1H NMR titrations and solvation effect confirmed hydrogen interaction between the receptors and anion.The results indicate that the affinity is related to the number of hydrogen bond.Hence,the receptors 1,2 and 3 can act as fluoride ion sensors even in the presence of other hahide ions.
基金supported by the National Key Research and Development Program of China(No.2019YFA0706900)the National Natural Science Foundation of China(Nos.22022703 and 22177108)the Collaborative Innovation Program of Hefei Science Center,CAS(No.2022HSC-CIP013).
文摘The 2-hydroxy-4-methoxybenzyl(Hmb)backbone modification can prevent amide bond-mediated sidereactions(e.g.,aspartimide formation,peptide aggregation)by installing the removable Hmb group into a peptide bond,thus improving the synthesis of long and challenging peptides and proteins.However,its use is largely precluded by the limited Hmb’s installation sites.In this report,an improved installation of Hmb(iHmb)method was developed to achieve the flexible installation and the convenient removal of Hmb.The iHmb method involves two critical steps:(1)oxidative diazotization of the readily installed 2-hydroxy-4-methoxy-5-amino-benzyl(Hmab)to give 2-hydroxy-4-methoxy-5-diazonium-benzyl(Hmdab)by combining soamyl nitrite(IAN)/HBF_(4),and(2)reductive elimination of Hmdab to give the desired Hmb by 1,2-ethanedithiol(EDT).The iHmb method enables the installation of Hmb at any primary amino acid including the highly sterically hindered amino acids(e.g.,valine and isoleucine).The practicality and utility of the iHmb method was demonstrated by one-shot solid-phase synthesis of a challenging aspartimide-prone peptide,the mirror-image version of a hydrophobic peptide and a long-chain peptide up to 76-residue.Furthermore,the iHmb method can be utilized to facilitate chemical protein ligation,as exemplified by the synthesis of the single-spanning membrane protein sarcolipin.The iHmb method expands the toolkit for peptide synthesis and ligation and facilitates the preparation of peptides/proteins.
基金the National Natural Science Foundation of China (Grant Nos. 20371040 & 20671077)the Natural Science Foundation of Gansu Province (Grant No. 3YS051-A25-01)the Key Project of Chinese Ministry of Education (Grant No. 205161)
文摘Azo-salicylaldehyde Schiff base-typed receptors containing an acidic H-bond donor moiety were syn-thesized and characterized. The UV-Vis data indicate that these receptors could act as selective col-orimetric sensors for basic anions and acidic species hydrogen sulfate by different color changes in a water-containing medium. The experiment of Brφnsted acid-base reaction by adding the sodium hy-droxide or perchloric acid revealed that the mechanism of recognition of anions might be deprotona-tion/protonation of the OH fragments by interacting with different anions and that the deprotona-tion/protonation process is fully reversible. The deprotonation/protonation of the receptors is respon-sible for the dramatic color change.
