81778-07-6Relevant articles and documents
Preparation method of clomazone
-
Paragraph 0003-0004, (2021/06/26)
The invention relates to a preparation method of clomazone. The method comprises: by taking hydroxylamine hydrochloride as a raw material, dropwise adding chloro pivaloyl chloride under the action of a self-made ether catalyst to obtain an intermediate 3-chloro-N-hydroxyl-2, 2-dimethyl propionamide with high yield, then cyclizing to prepare 4, 4-dimethyl-3-isoxazolone, and carrying out benzylation under pioneered caustic soda flake catalysis without separation to directly prepare 2-(2-chlorphenyl) methyl-4, 4-dimethyl-3-isoxazolone. Compared with existing literature methods, the method of the invention has the advantages that the self-made ether catalyst is innovatively used, so that the yield in the first step is remarkably improved, and the content and optical purity of the product are high; in the final benzylation reaction, caustic soda flakes are used to improve the yield, and water is used as a solvent in the whole reaction process, so that the cost is low, the recovery and post-treatment are simple, the reaction is mild, and the intermediate control is simple; and the preparation method provided by the invention has the advantages of easily available reaction raw materials, mild reaction, high yield, simple separation and purification, low cost and environment-friendly preparation process.
Purification method of intermediate 4,4-dimethyl isoxazole-3-ketone
-
Paragraph 0023-0027; 0035-0040; 0048-0053; 0061-0066; 0074-, (2021/01/25)
The invention discloses a purification method of an intermediate 4,4-dimethyl isoxazole-3-one, which comprises the following steps: washing a 4,4-dimethyl isoxazole-3-one reaction solution with pure water until the pH value of the oil phase of the reaction solution is 7.5-9.0, dissolving with alcohol, distilling, refluxing, acidifying, crystallizing and filtering to obtain the solid 4,4-dimethyl isoxazole-3-one with a purity of 99.5% or above. The purification process is simple, the post-treatment is highly operable, the key technical problems of low product purity, difficulty in refining andinfluence on the purity of the subsequent product clomazone in the original 4,4-dimethyl isoxazole-3-ketone preparation technology are solved, and the purification process conforms to the concept of green economic cycle.
Low-temperature synthesis process of clomazone
-
Paragraph 0025; 0028; 0031; 0034; 0037; 0040, (2019/09/05)
The invention discloses a low-temperature synthesis process of clomazone. The low-temperature synthesis process of the clomazone comprises condensation reaction, cyclization reaction, synthesis reaction and configuration conversion. The low-temperature synthesis process of the clomazone disclosed in the invention starts from analyzing side reaction products, determines the chemical composition ofimpurities, and reduces the amount of the impurities by optimizing process parameters, finding high-efficiency catalysts and controlling side reactions; then, through chemical treatment on the produced isomers, part of the isomers are converted into the product, and part of irreversible by-products are converted into high-boiling-point polymer compounds through reaction, so that the clomazone product is easy to separate; finally, the clomazone product is purified through physical methods to obtain the clomazone with a purity greater than 97%.
Preparation method of clomazone
-
Paragraph 0017; 0020; 0023; 0026, (2017/08/29)
The invention relates to a preparation method of clomazone, wherein an intermediate, 4,4-dimethylisoxazole-3-one, is synthesized by dropwise adding chloro-pivaloyl chloride to a raw material, hydroxylamine hydrochloride, under the effects of a self-made ether catalyst; and then the intermediate is condensed with o-chlorobenzyl chloride under the effects of a caustic soda flake catalyst to synthesize a raw drug of the clomazone. The preparation method uses easy-to-obtained raw materials and mild reactions, is high in yield and is simple in separation and purification, has low cost, is environment-friendly, and has great industrial application prospect.
PROCESS FOR PREPARING CLOMAZONE, NOVEL FORM AND USE OF THE SAME
-
Page/Page column 15; 16, (2015/01/16)
A process for preparing clomazone is provided,the process comprising reacting 4,4-dimethyl-3-isoxazolidinone with 2-chlorobenzyl chloride in an aqueous medium in the presence of a base, in particular an alkali metal hydroxide. A method for preparing clomazone is also disclosed, the method comprising (a) crystallizing clomazone from solution in an organic solvent; and (b) isolating the resulting crystals. N-benzene is a particularly suitable solvent. Further, there is provided Form I crystalline 2-[(2-chlorophenyl)methyl]-4,4-dimethyl-3-isoxazolidinone (clomazone), wherein the polymorph Form I is characterized by at least one of the following properties : (i) an X-ray powder diffraction pattern having characteristic peaks expressed in degrees 2θ(+/-0.20° θ) at one or more of the following positions : about 10.63, 16.07, 18.08, 19.11, 19.34, 21.20, 24.78 and 28.80; and (ii) an infrared (IR) spectrum having a characteristic peak : at about 2967 and 2870 cm-1.
3-Aminoxypropionate-based linker system for cyclization activation in prodrug design
Ge, Yiyu,Wu, Xinghua,Zhang, Dazhi,Hu, Longqin
scheme or table, p. 941 - 944 (2009/08/15)
A novel linker system based on 3-aminoxypropionate was designed and evaluated for drug release using proteolysis as an activation trigger followed by intramolecular cyclization. The hydroxylamine moiety present in the linker system enabled faster release of the parent drug from the linker-drug conjugate at lower pH as compared to an aliphatic amine moiety. Introduction of two methyl groups strategically at the α position to the carboxylate in the linker further improved the rate of cyclization by nearly 2-fold. The 3-aminoxypropionate linker was successfully applied to a model prodrug for protease activation using α-chymotrypsin as the activating enzyme; the activation of the model prodrug bearing the 3-aminoxypropionate linker was 136 times faster than the corresponding model prodrug bearing an amine linker.
SUBSTITUTED ISOXAZOLIDIN-3-ONES AND DERIVATIVES THEREOF ACTING AT MUSCARINIC RECEPTORS
-
, (2008/06/13)
Substituted isoxazolidin-3-ones and derivatives thereof are described, as well as methods for the preparation and pharmaceutical compositions of same, which are useful as centrally acting muscarinic agents and are useful as analgesic agents for the treatment of pain, as sleep aids and as agents for treating the symptoms of senile dementia, Alzheimer's disease, Huntington's chorea, tardive dyskinesia, hyperkinesia, mania, or similar conditions of cerebral insufficiency characterized by decreased cerebral acetylcholine production or release.
Processes for producing herbicide intermediates
-
, (2008/06/13)
Processes for producing 4,4-dimethyl-3-isoxazolidinone and intermediates for it from known and inexpensive starting materials are described and exemplified.
Herbicidal 3-isoxazolidinones and hydroxamic acids
-
, (2008/06/13)
Novel 3-isoxazolidinone compounds and novel hydroxamic acid intermediates from which they are prepared exhibit herbicidal activity to grassy and broad-leaf plant species while leaving legumes, especially soybeans, unaffected. The preparation and herbicidal activity of the compounds is exemplified.