3—氮杂环取代色酮的合成

报道了通过１－苯基－３－甲酰基－１，２，５－三唑合成３－杂环取代色酮的结果。化合物的结构经元素分析，紫外光谱，红外光谱，１ＨＮＭＲ及１３ＣＮＭＲ谱证实。     

2-R-6-ethyl-7-hydroxy-3-(5-phenyl-1,3,4-thiadiazolyl-2)chromones

-(5-Phenyl-1,3,4-thiadiazolyl-2)-6-ethyl-2,4-dihydroxyacetophenone was synthesized by the condensation of 4-ethylresorcinol with 2-cyanomethyl-5-phenyl-1,3,4-thiadiazole. Interaction of the former with carboxylic acid anhydrides and halides and subsequent hydrolysis gave 2-R-6-ethyl-7-hydroxy-3-(5-phenyl-1,3,4-thiadiazoyl)chromones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, 1840–1847, December, 2004.     

Gas phase reaction between chromones and solvent in an electrospray ionization source

Chromones were measured by using electrospray ionization mass spectrometry in negative mode. Interestingly, in addition to the deprotonated ion ([M ? H]^?), unexpected [M + 17]^? and [M + 31]^? ions were observed in high intensity when water and methanol were used as the solvent. Chromones with different substitutes were tested. Compared with the deprotonated ion, [M + 17]^? and [M + 31]^? ions were observed with higher abundances when the C‐3 site of chromones was substituted by electron withdrawing groups. Based on high performance liquid chromatography‐mass spectrometry (LC‐MS), deuterium‐labeling and collisional‐induced dissociation experiments, a covalent gas‐phase nucleophilic addition reaction between chromone and water, and the formation of a noncovalent complex between chromone and methanol were proposed as the mechanism for the observed [M + 17]^? and [M + 31]^? ions, respectively. Understanding and using these unique gas phase reactions can avoid misannotation when analyzing chromones and their metabolites.     

Reactions of ethyl 5,6,7,8-tetrafluoro-2-methylchromone-3-carboxylate and 3-acetimidoyl-5,6,7,8-tetrafluoro-4-hydroxycoumarin with S-nucleophiles

The reactions of ethyl 5,6,7,8-tetrafluoro-2-methylchromone-3-carboxylate with mercaptoacetic acid and 1,2-ethanedithiol afforded C(7)-substitution products. The above-mentioned chromone reacted with 2-mercaptoethanol to yield 7-mono- or 5,7,8-trisubstituted products depending on the reaction conditions. The reaction of 3-acetimidoyl-5,6,7,8-tetrafluoro-4-hydroxycoumarin with 2-mercaptoethanol afforded a 5,7,8-trisubstituted produect. The acyl-lactone rearrangement of mono- and trisubstituted chromones yielded the corresponding coumarins. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1557–1561, August, 1999.