5061-21-2Relevant articles and documents
A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones
Hosono, Kazumi,Kodama, Shintaro,Nomoto, Akihiro,Ochi, Takanori,Ogawa, Akiya,Tabuchi, Akihiro,Yamamoto, Yuki,Yamazaki, Kento
supporting information, p. 2906 - 2914 (2022/01/12)
A simple and efficient method for α-brominating lactones that affords α-bromolactones under mild conditions using tetraalkylammonium hydroxide (R4N) as a base was developed. Lactones are ring-opened with Br2 and a substoichiometric amount of PBr3, leading to good yields of the corresponding α-bromocarboxylic acids. Subsequent intramolecular cyclization over 1 h using a two-phase system (H2O/CHCl3) containing R4N afforded α-bromo lactones in good yields. This method can be applied at the 10 mmol scale using simple operations. α-Bromo-δ-valerolactone, which is extremely reactive and difficult to isolate, could be isolated and stored in a freezer for about one week using the developed method. Optimizing the solvent for environmentally friendly large-scale syntheses revealed that methyl ethyl ketone (MEK) was as effective. In addition, in situ-generated α-bromo-δ-valerolactone was directly converted into a sulfur-substituted functional lactone without difficulty by reacting it with a sulfur nucleophile in one pot without isolation. This new bromination system is expected to facilitate the industrial use of α-bromolactones as important intermediates.
Synthetic method for glufosinate ammonium
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Paragraph 0034; 0035, (2019/02/04)
The invention relates to a synthetic method for glufosinate ammonium. The synthetic method comprises the following steps: single-bromine substitution, amination, amino protection, chlorination ring opening, Arbuzov reaction and acidizing hydrolysis ammoniation; the single-bromine substitution means triggering alpha-site single-bromine substitution betweengamma-butyrolactone I and bromine under theexistence of catalyst and performing reduced pressure distillation, thereby acquiring a pure intermediate II alpha-bromine-gamma-butyrolactone; phosphorus tribromide is served as the catalyst; amination means triggering amination reaction between alpha-bromine-gamma-butyrolactone II and ammonium hydroxide, and then adding hydrochloric acid and reflowing, thereby acquiring an intermediate IIIalpha-amino-gamma-butyrolactone hydrochloride. The invention has the beneficial effects: 1) low-costgamma-butyrolactone is taken as a raw material, is subjected to single-bromine substitution with bromineand then is subjected to amination reaction with ammonium hydroxide; the adopted raw materials are low-cost and easily acquired; reaction conditions are mild; operation is simple and convenient; safety is high; amplifying production is feasible; reaction yield is high; product purity is high; cost is greatly lowered; the synthetic method is suitable for industrial production.
A method of manufacturing a brominated lacton compd.
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Paragraph 0052; 0079-0081; 0082; 0085; 0086; 0088, (2018/11/22)
PROBLEM TO BE SOLVED: To provide a method for producing a brominated lactone compound inexpensively and efficiently.SOLUTION: This method for producing a brominated lactone compound includes a bromination step of making bromine react with a lactone compound represented by formula (1) (in the formula, R represents 3-5C linear hydrocarbon group, wherein the hydrocarbon group may be replaced with a hydrocarbon group, carbonyl, oxo, amino, hydroxyl, alkoxyl, acyl, acyloxy or a halogen atom, while one or more hydrogen atoms are bonded to a carbon which is the nearest to a ketone group adjacent to R among carbons constituting R). The bromination step is performed in the presence of at least one catalyst selected from a group comprising sulfur and a sulfur compound.
