97-51-8Relevant articles and documents
Phosphine-catalyzed sequential (2+3)/(2+4) annulation of γ-vinyl allenoates: Access to the synthesis of chromeno[4,3-: B] pyrroles
Huang, You,Li, Xiaohu
supporting information, p. 9934 - 9937 (2021/10/12)
A phosphine-catalyzed cascade (2+3)/(2+4) cyclization reaction of γ-vinyl allenoates with aldimine esters has been developed to provide a series of chromeno[4,3-b]pyrrole derivatives that contain three contiguous stereogenic centers. The method gives a good yield, excellent chemoselectivity and diastereoselectivity under mild conditions.
Method for synthesizing mesalazine
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Paragraph 0011; 0037-0040, (2020/08/25)
A method for synthesizing mesalazine is disclosed. The method comprises the following steps: 1) adding p-nitrophenol, p-toluenesulfonic acid, absolute ethyl alcohol and hexamethylenetetramine, stopping heating after the reaction is finished, heating to room temperature while stirring with ice water, separating out solids, filtering, washing and drying to obtain 5-nitrosalicylaldehyde; 2) adding the 5-nitrosalicylaldehyde, potassium tert-butoxide, copper salt and acetonitrile, adding tert-butyl hydroperoxide while stirring, after the reaction is finished, performing vacuum concentration to remove the solvent, pouring cold water into residues, stirring, performing suction filtration, adjusting the pH value of the filtrate with hydrochloric acid, performing suction filtration, and drying to obtain 5-nitrosalicylic acid; and 3) adding stannous chloride dihydrate, concentrated hydrochloric acid, the 5-nitrosalicylic acid and ethanol, carrying out vacuum concentration after the reaction is finished, dissolving residues in water, adjusting the pH value with a concentrated hydrochloric acid solution, standing for crystallization, carrying out suction filtration, washing filter cake with water, and drying to obtain mesalazine. No isomer is generated, and the yield is high; the method does not need high-temperature and high-pressure conditions; the reaction cost is low; and raw materialsand auxiliary materials with high toxicity and heavy environmental pollution are not used.
Catalytic oxidation of alcohols and alkyl benzenes to carbonyls using Fe3O4?SiO2?(TEMPO)-: Co -(Chlorophyll-CoIII) as a bi-functional, self-co-oxidant nanocatalyst
Hamah-Ameen, Baram Ahmed,Kazemnejadi, Milad,Mahmoudi, Boshra,Rostami, Amin
, p. 6600 - 6613 (2020/11/16)
Chlorophyll b was extracted from heliotropium europaeum plant, demetalated, allylated and grafted to acrylated TEMPO through a copolymerization protocol. Then, the chlorophyll monomers were coordinated to Co ions, immobilized on magnetic nanoparticles and the resulting hybrid was used as a powerful catalyst for a variety of oxidation reactions. By using the present method, oxidation of benzylic alcohols and alkyl benzenes to carbonyls was accomplished in water under aerobic conditions. Moreover, direct oxidation of alcohols to carboxylic acids was performed by adding NaOCl to the mixture. All entries were oxidized to the corresponding desired product with high to excellent yields and up to 97% selectivity. The catalyst was thoroughly characterized by CV, TGA, VSM, XRD, XPS, DLS, FE-SEM, TEM, UV-Vis, EDX, and BET analyses. The activity of the catalyst was investigated by applying various components of the catalyst to the oxidation model separately. The reasonable mechanisms are suggested based on the cooperation between the TEMPO groups and cobalt(iii) (or Co(iv)) sites on the catalyst. The catalyst could be recovered and reused for at least 7 consecutive recycles without any considerable reactivity loss. This journal is