- Method for synthesizing 2-amino-5-nitrothiazole
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The invention discloses a method for synthesizing 2-amino-5-nitrothiazole, which comprises the following steps: (1) in an inert atmosphere, adding diethylamine, acetyl chloride and triethyl orthoacetate into a reaction container, uniformly mixing, stirring to react for 12-24 hours, and distilling and purifying the reaction product to obtain N, N-dimethylformamide dimethyl acetal, (2) in an inert atmosphere, mixing N, N-dimethylformamide dimethyl acetal with nitromethane, heating the mixture to 80-100 DEG C for reflux reaction, carrying out reduced pressure distillation on the reaction productto remove the solvent, and purifying to obtain N, N-dimethyl nitroethylene, and (3) in an inert atmosphere, putting N, N-dimethyl nitroethylene into a reaction container, sequentially adding ethanol,liquid bromine and thiourea, reacting at room temperature, after the reaction is finished, filtering a reactant, washing with ice ethanol, drying to obtain a white solid, adding water, and filtering to obtain the 2-amino-5-nitrothiazole. According to the method for synthesizing 2-amino-5-nitrothiazole, the raw materials are easy to obtain, the cost is low, and the yield can reach 60%.
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Paragraph 0037-0039; 0043-0050
(2020/08/06)
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- Environment-friendly preparation method of N,N-dimethylformamide dimethylacetal
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The invention relates to the field of organic synthesis, in particular to an environment-friendly preparation method of N,N-dimethylformamide dimethylacetal. The preparation method comprises the following steps that sodium methoxide and chloroform generates dimethoxy chloromethane under the action of a catalyst; the dimethoxy chloromethane obtained in the last step is reacted with dimethylamine toobtain the N,N-dimethylformamide dimethylacetal. The preparation method has the advantages that hypertoxic dimethyl sulfate is prevented from being used; only through simple treatment, sodium chloride generated by the reactions can be used as a byproduct for sales, the yield of solid wastes can be reduced, and the economic benefits of the product can be increased.
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Paragraph 0026-0045
(2019/07/29)
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- Preparation method of azoxystrobin intermediate
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The invention relates to a preparation method of an azoxystrobin intermediate. According to the method, a compound shown in a formula (II) serves as a raw material and reacts with a methylating agentunder a basic condition to obtain the azoxystrobin intermediate shown in a formula (I), wherein Z1 represents halogen. The method has the advantages that the reaction time is short, the total yield ishigh, the cost of raw materials is low, and the method is suitable for large-scale production and has very important significance for industrial production of final products of azoxystrobin. The formula (II) and the formula (I) are shown in the description.
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Paragraph 0036; 0037; 0038
(2018/09/29)
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- N,N-dimethylformamide dimethyl acetal synthesis method
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The invention discloses an N,N-dimethylformamide dimethyl acetal synthesis method. The synthesis method includes: subjecting N,N-dimethylformamide and dimethyl sulfate to reaction to generate an imine complex, and subjecting the imine complex and solid sodium methylate dispersed in an organic solvent to reaction to obtain N,N-dimethylformamide dimethyl acetal, wherein the organic solvent refers to at least one of isoparaffin, solvent oil and white oil. By adoption of the novel organic solvent, reaction conditions (with the temperature being 20-30DEG C) of the imine complex and the sodium methylate can be lowered, and the reaction conditions are milder. In addition, when the reaction temperature is compared with an original reaction temperature ranging from -5 DEG C to 0 DEG C, products generated after reaction are quicker in dissolution and can be timely dissolved in the organic solvent to be wrapped by the organic solvent, so that by-product generation is avoided, and yield is increased. According to experiments, yield of the N,N-dimethylformamide dimethyl acetal can reach 85% above.
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Paragraph 0034-0037; 0048-0049
(2017/06/13)
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- Novel process for preparing 4,4-difluoro-((2-dialkylamino) methylene)-3-oxobutanic acid alkyl ester
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The present invention relates to a novel method for preparing 4,4-difluoro-((2-dialkylamino) methylene)-3-oxobutanic acid alkyl ester which is represented by the following chemical formula ( I ) and useful as a manufacturing intermediate for fungicides such as isopyrazam, sedaxane, bixafen and the like. In the formula ( I ), R 1 and R 2 are each a C 1 to C 4 alkyl group, and R is a methyl group or an ethyl group. The compound of the formula ( I ) is produced by reacting dialkylformamide dialkyl acetal with a difluoro ketoester.
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Paragraph 0053
(2017/01/31)
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- Bredereck's reagent revisited: Latent anionic ring-opening polymerization and transesterification reactions
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The ring-opening polymerization of lactide with commercially available Bredereck-type reagents in the presence or absence of alcohol initiators was carried out affording polylactide with controlled molecular weight and narrow polydispersities. An anionic mechanism involving heterolytic cleavage to alkoxides is proposed, where these reagents function as latent anionic initiators for the ring-opening polymerization of lactide.
- Csihony, Szilard,Beaudette, Tristan T.,Sentman, Alan C.,Nyce, Gregory W.,Waymouth, Robert M.,Hedrick, James L.
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p. 1081 - 1086
(2007/10/03)
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- SYNTHESIS OF INDOLIZINES
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Disclosed are methods of preparing substituted indolizines represented by the following formula: comprising reacting a substrate represented by the following formula: with either the cyclization reagent of the following formula: or, a reagent prepared by reacting the compound represented the formula below with an alkylating agent: The variables in the above formulas are defined herein.
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- Novel Syntheses of 2-Butyl-5-chloro-3H-imidazole-4-carbaldehyde: A Key Intermediate for the Synthesis of the Angiotensin II Antagonist Losartan
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Reaction of glycine methyl ester (19) with imidate 18 under carefully optimized conditions allowed preparation of the rather unstable imidazolinone 11 in ca. 90% yield. Reaction of 11 with POCl3/ DMF followed by aqueous workup gave aldehyde 2, a key intermediate for the synthesis of the angiotensin II antagonist Losartan, in ca. 55% yield. Structural identification of intermediates and byproducts formed during both the reaction to prepare 11 and the reaction of 11 with POCl3/DMF allowed development of several closely related syntheses of aldehyde 2.
- Griffiths, Gareth J.,Hauck, Michael B.,Imwinkelried, Rene,Kohr, Joerg,Roten, Conrad A.,Stucky, Gerhard C.,Gosteli, Jacques
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p. 8084 - 8089
(2007/10/03)
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- Unexpected formation of acylformamidines by reaction of primary carboxamides with MeONa in DMF in the presence of CHCl3
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Dichlorocarbene, which is generated by reaction of CHCl3 with MeONa, is likely to chlorinate DMF to produce tile Vilsmeier-Haack-Arnold salt that in the presence of excess MeONa, gives DMF dimethylacetal (2). This latter reacts with primary amides to yield the corresponding N,N-dimethyl-N'-acylformamidines. Solid state structure of N-[(dimethylamino)methylene]phenoxyacetamide (4) obtained by X-ray crystallography is also reported.
- Anelli, Pier Lucio,Brocchetta, Marino,Copez, Debora,Palano, Daniela,Visigalli, Massimo,Paoli, Paola
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p. 15827 - 15832
(2007/10/03)
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- Oxazolidinone derivatives and pharmaceutical compositions containing them
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The present invention provides agents having high antimicrobial activity for preventing and treating infectious diseases. Thus, the present invention provides novel oxazolidinone derivatives represented by chemical formula (I), or pharmaceutically acceptable salts thereof, as well as antimicrobial compositions containing said derivatives or salts thereof as active ingredients. STR1
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- Preparation of 1-nitroanthraquinone-2-carboxylic acid
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1-Nitroanthraquinone-2-carboxylic acid of the formula I STR1 is prepared by treating novel 2-substituted 1-nitroanthraquinones of the general formula II STR2 where R is --CH=CH--R1 or --CH2 --CHO, where R1 is C1 -C5 -dialkylamino or a cyclic 5- or 6-membered amine which may contain further hetero atoms, with oxidizing agents free of heavy metal.
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- Synthese regiospecifique d'amines tertiaires a groupe secondaire bi-insature
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We describe the regiospecific preparation of tertiary amines with a symmetrical (or dissymetrical) doubly unsaturated secondary group, by reaction of an allylic, vinylic or acetylenic organometallic derivative with a dialkylformamido acetal, a chlorinated iminium salt or an alkynyl aminoether.
- Mesnard, D.,Miginiac, L.
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- Alkyl 2-carboalkoxy-3,4-dialkoxybenzenecarbamates and process for their preparation
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A process for the preparation of alkyl 2-carboxy-3,4-dialkoxybenzenecarbamates is described. The carbamates are useful intermediates in the preparation of 8-halo-5,6-dialkoxyquinazoline-2,4-diones. The diones are useful as cardiotonic agents.
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- MOLECULAR COMPLEXES OF CHLOROFORM WITH ORTHO ESTERS.
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The authors studied the relative basicity of several esters of orthocarboxylic acids in the complexation reaction with chloroform by PMR spectroscopy. In accordance with data obtained, linear and cyclic acetals of amides have the highest basicity, and show the highest tendency to form complexes among compounds I-XX studied, so that these compounds can be recommended as effective extractants and flotation reagents. Comparison of the proton-donor activity of acetals and ortho esters shows that the latter can be successfully used as solvents in protective coatings and polymer materials.
- Lapuka,Rudkevich,Kostyukevich,Kurbanov,Pastushenko,Zlotskii,Rakhmankulov
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p. 701 - 706
(2007/10/02)
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- 4-Heteroarylimidazo-[1,5-A]pyrimidines
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Novel pyrimidine compounds are disclosed of the class represented by the formula: STR1 wherein R1 is selected from the class consisting essentially of hydrogen, chloro, bromo, cyano (--CN), carbamoyl (--CO--NH2), carboxyl (--COOH), and lower alkoxycarbonyl (--CO--O--R3, where R3 is a lower alkyl radical having 1-4 carbon atoms), and wherein R2 is a monovalent radical selected from the class consisting essentially of furyl, thienyl, 3-pyridyl and 3-pyridyl-N-oxide, either of said pyridyl radicals optionally being substituted with an alkyl radical having from 1 to 4 carbon atoms. Processes of preparing such compounds are disclosed. The novel compounds are useful as anxiolytic agents in ameliorating anxiety in a mammal.
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