Two practical methods for highly stereoselective synthesis of (Z)-2-acylamido-4-phenylcrotonates 2a similar to b have been developed. The key step in the first route was how to control the acid-catalyzed isomerization...Two practical methods for highly stereoselective synthesis of (Z)-2-acylamido-4-phenylcrotonates 2a similar to b have been developed. The key step in the first route was how to control the acid-catalyzed isomerization of condensation mixtures of alpha-keto ester 5 with carbomite. In the second route the key step was reduction of oxime 8, derived from alpha-keto ester 5, with iron powder in the presence of acetic anhydride.展开更多
Synthesis of a novel series of N-pyrandione substituted amino acids and their esters 3 via a condensation reaction between pyrandione and amino acid or their derivatives in excess ethyl orthoformate without solvent is...Synthesis of a novel series of N-pyrandione substituted amino acids and their esters 3 via a condensation reaction between pyrandione and amino acid or their derivatives in excess ethyl orthoformate without solvent is described. The stereochemistry of 3 has been discussed.展开更多
As a potential photochromic system,acylhydrazones exhibit many outstanding adva ntages including low cost,simple synthesis and high modifiability compared with some classic photochromic systems.However,the absorption ...As a potential photochromic system,acylhydrazones exhibit many outstanding adva ntages including low cost,simple synthesis and high modifiability compared with some classic photochromic systems.However,the absorption wavelengths of acylhydrazones usually locate in ultraviolet regio n,which makes the band separation between the absorbance maxima of its irradiated and unirradiated forms cannot be observed by naked eyes and greatly limits their practical applications.In this work,a simple strategy for constructing acylhydrazone photochromic system with visible color/emission change is provided.Rhodamine 6 G hydrazine-2-aldehyde-pyridine Schiff base(compound 3)is designed and synthesized by combining acylhydrazone with Rhodamine 6 G structure.The introduction of Rhodamine 6 G moiety to 3 not only makes it remain all the advantages of acylhydrazone photochromic system but also exhibits visible photo-induced color/emission changes both in solution and in a solid matrix.Moreover,3 exhibits reversible photochromic property with good fatigue re sistance,which makes it an excellent candidate for p hoto-patterning.展开更多
文摘Two practical methods for highly stereoselective synthesis of (Z)-2-acylamido-4-phenylcrotonates 2a similar to b have been developed. The key step in the first route was how to control the acid-catalyzed isomerization of condensation mixtures of alpha-keto ester 5 with carbomite. In the second route the key step was reduction of oxime 8, derived from alpha-keto ester 5, with iron powder in the presence of acetic anhydride.
基金the National Natural Science Foundation of China for the project support (No.29832050)
文摘Synthesis of a novel series of N-pyrandione substituted amino acids and their esters 3 via a condensation reaction between pyrandione and amino acid or their derivatives in excess ethyl orthoformate without solvent is described. The stereochemistry of 3 has been discussed.
基金the National Natural Science Foundation of China(Nos.U1904172,21501150,51502079 and 21671174)Key Scientific and Technological Project of Henan Province(No.202102310006)。
文摘As a potential photochromic system,acylhydrazones exhibit many outstanding adva ntages including low cost,simple synthesis and high modifiability compared with some classic photochromic systems.However,the absorption wavelengths of acylhydrazones usually locate in ultraviolet regio n,which makes the band separation between the absorbance maxima of its irradiated and unirradiated forms cannot be observed by naked eyes and greatly limits their practical applications.In this work,a simple strategy for constructing acylhydrazone photochromic system with visible color/emission change is provided.Rhodamine 6 G hydrazine-2-aldehyde-pyridine Schiff base(compound 3)is designed and synthesized by combining acylhydrazone with Rhodamine 6 G structure.The introduction of Rhodamine 6 G moiety to 3 not only makes it remain all the advantages of acylhydrazone photochromic system but also exhibits visible photo-induced color/emission changes both in solution and in a solid matrix.Moreover,3 exhibits reversible photochromic property with good fatigue re sistance,which makes it an excellent candidate for p hoto-patterning.
