7128-64-5Relevant articles and documents
Metal-Free Oxidative Condensation of Catechols, Aldehydes and NH4OAc towards Benzoxazoles
Dong, Jianyu,Geng, Furong,Su, Lebin,Wu, Shaofeng,Yin, Shuang-Feng,Zhou, Dan,Zhou, Yongbo
supporting information, p. 3607 - 3614 (2021/07/28)
Benzoxazoles extensively exist in biologically active compounds, natural products, pharmaceuticals and functional materials. Thus, facile and green synthesis of such valuable compounds from easily available substrates will make a contribution to drug, material, and fine chemistry. A method for the synthesis of benzoxazoles from catechols, aldehydes and ammonium acetate is developed using NaIO4 as oxidant under metal- and additive-free conditions. A broad range of benzoxazoles including some fluorescent whitening agents, JTP-426467 and tafamidis analogues are synthesized in 56–95% yields with outstanding functional group tolerance. Mechanistic investigations suggest that an interesting o-iminocyclohexa-diene alcohol intermediate is involved in the reaction. These salient features of the protocol make it an alternative for the synthesis of benzoxazoles. (Figure presented.).
Production process of fluorescent whitening agent OB
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Paragraph 0022-0050, (2021/03/13)
The present invention relates to a production process of a fluorescent whitening agent OB. The production process specifically comprises the following steps: adding trichlorobenzene to a material feeding kettle, starting stirring, sequentially adding OB phenol, OB acid and a catalyst boric acid, pumping toluene into the material feeding kettle, uniformly stirring, pumping into a condensation kettle through a material pouring pump, introducing 99.9% nitrogen gas into the condensation kettle, and preventing the material from being oxidized, heating the material to 160-180 DEG C, starting a condensation dehydration reaction, continuing heating reaction dehydration until the temperature of the material is increased to 230-250 DEG C, evaporating methylbenzene in the dehydration process, and ending the reaction when no water is removed from the reaction material; then starting system negative pressure to evaporate trichlorobenzene out of the condensation kettle until trichlorobenzene is completely evaporated out so as to obtain a molten crude product material; the process is simple in process, high in yield and high in product purity.
Process for preparing particles which have a hydrophilic core coated with a hydrophobic polymeric layer
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, (2016/06/01)
This method of preparing particles having a hydrophilic core coated with a hydrophilic core coated with a hydrophobic polymeric layer includes the steps of: preparing an aqueous phase comprising at least one hydrophilic optical brightener or colorant; preparing an organic phase including at least one hydrophobic polymer; forming a water-in-oil inverse emulsion by adding the aqueous phase into the organic phase; forming the particles by thermal quenching of the emulsion; and isolating the particles thus obtained.
Process for the preparation of bis-benzazolyl compounds
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Page/Page column 3, (2008/06/13)
The present invention provides a process for the preparation of a compound of formula (I) wherein Y represents —O—, —S— or —N(R2)—, R2 being hydrogen, C1-C10alkyl or aralkyl; Z represents a 2,5-furanyl, 2,5-thiophenyl, 4,4′-stilbenyl or a 1,2-ethyleny residue and R1 represents hydrogen, halogen, C1-C10alkoxyl, cyano, COOM or SO3M, M being hydrogen or an alkaline or alkaline earth metal, characterized by reacting a compound of formula (II) with a dicarboxylic acid of formula (III): HOOC-Z-COOH, or an ester thererof, Y, Z and R1 being as previously defined, in N-methylpyrrolidone or N,N-dimethylacetamide, in the presence of an acidic catalyst and, optionally, in the presence of a secondary solvent capable of removing water from the reaction mixture, which are useful as optical whitening agents for natural and synthetic materials.
Eine einfache Methode zur Herstellung von Benzoxazolen
Seha, Zdenek,Weis, Claus D
, p. 413 - 419 (2007/10/02)
The preparation of benzoxazoles by a facile one-pot reaction is reported.The reaction of carboxylic acids with 2-chloro-N-methyl-Δ1-pyrrolinium chloride in an excess of N-methyl-2-pyrrolidone afforded carboxylic acid chlorides which were converted subsequently to their 2-hydroxyanilides by addition of 2-aminophenols.Cyclization of the 2-hydroxy-anilides at elevated temperatures furnished the benzoxazoles in high yield and purity.
