- Diazo coupling proces
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The invention relates to a diazo coupling process. An aromatic primary amine compound solution and a nitrite solution are pumped into a static mixer through a pump to be mixed and then enter a continuous reactor to react. Generated diazotization reaction liquid is sprayed into a reaction kettle through a spraying system and reacts with a coupling component pumped into the reaction kettle to prepare a product. The diazo coupling proces is a brand-new diazo coupling process which is not reported in the prior art. According to the diazo coupling proces, the fully continuous process is achieved, the continuous flow reaction and the kettle type reaction are combined, the spraying system is independently arranged, the reaction units are connected in series for the reaction, and the high-yield and high-purity product is prepared on the continuous basis.
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Paragraph 0023; 0030-0038
(2021/06/22)
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- Preparation method of salazosulfapyridine
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The invention relates to the technical field of sulfasalazine, in particular to a synthesis process of salazosulfapyridine. Nitroso compound and ammonia are condensed to obtain salazosulfapyridine; byadopting the technical scheme provided by the invention, the reaction temperature does not need to be strictly controlled, and unstable diazonium salt can be avoided, so that the generation of by-products is avoided, and by utilizing the technical scheme provided by the invention, the product salazosulfapyridine can be directly separated out through simple treatment, and the reaction yield is high.
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Paragraph 0016
(2020/07/13)
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- Preparation method of sulfasalazine
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The invention relates to the technical field of sulfasal, in particular to a synthesis technology of environment-friendly sulfasalazine. A nitroso compound is condensed with ammonia to obtain the sulfasalazine. After adoption of the technical scheme, raw materials are cheap, easy to obtain and stable, and production of unstable diazonium salt is avoided, so that production of a byproduct is avoided; after adoption of the technical scheme, the product sulfasalazine can be directly separated out through simple treatment, so that the reaction yield is high.
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Paragraph 0012; 0032-0060
(2018/07/30)
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- Method for synthesizing salazosulfapyridine using pyridazol as raw material
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The present invention discloses a method for synthesizing salazosulfapyridine. The synthetic method comprises: step 1, conducting a diazotization reaction on pyridazol using a pipe reactor under the action of hydrochloric acid and isoamyl nitrite in a THF solvent to obtain diazonium salt; and step 2, conducting a coupling reaction on the diazonium salt and salicylic acid in a sodium hydroxide aqueous solution. In the synthetic method provided by the present invention, pyridazol is used as the raw material, and salazosulfapyridine is obtained through the diazotization reaction and the coupling reaction successively, . The diazotization reaction and the coupling reaction have a relatively high conversion rate and relatively few side reactions, thereby improving the product purity and ensuring the yield. In addition, pyridazol is easily available in source, so that the production cost is lowered, and the method has relatively huge industrial production value.
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Paragraph 0032; 0033
(2017/01/19)
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- Method for synthesizing salazosulfapyridine by utilizing 2-aminopyridine as raw material
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The invention discloses a method for synthesizing salazosulfapyridine by utilizing 2-aminopyridine as a raw material. The method comprises the steps: step 1, performing a sulfamation reaction on 2-aminopyridine and para-acetylaminobenzene sulfonyl chloride in an aqueous solution of potassium carbonate; step 2, firstly performing hydrolyzation in DMSO-water mixed solution of sodium hydroxide, and then performing hydrochloric acid acidification; step 3, performing a diazo-reaction in an aqueous solution dissolving hydrochloric acid and sodium nitrite; step 4, performing a coupling reaction on diazonium salt and salicylic acid in an aqueous solution of sodium hydroxide. According to the method for synthesizing salazosulfapyridine by utilizing the 2-aminopyridine as the raw material, the 2-aminopyridine is taken as a starting raw material, and then is sequentially subjected to the sulfamation reaction, the hydrolyzation, the acidification, the diazo-reaction and the coupling reaction to obtain the salazosulfapyridine. The diazo-reaction and the coupling reaction have high conversation rate and a few side reaction so as to improve the purity of products and ensure the efficiency; furthermore, the source of the 2-aminopyridine is easy, the production cost is reduced, and the industrial production cost is large.
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- A method for preparing liu Danhuang pyridine (by machine translation)
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The invention discloses a method for preparing pyridine liu Danhuang. The preparation method is, the sulfonamide pyridine in 1st step is dissolved in the aqueous solution of hydrochloric acid and sodium nitrite diazotization reaction occurs in, the diazonium salt obtained; 2nd step, the diazonium salt reacts with the salicylic acid in the aqueous sodium hydroxide solution in pyridine liu Danhuang coupling reaction product obtained; the 3rd step pyridine liu Danhuang purification of crude to carry on. In the preparation method of this invention, to sulfonamide pyridine as the starting material, to a first sequentially after the diazotization reaction, coupling reaction, purification, get liu Danhuang pyridine. Diazotization reaction-coupling reaction has a high conversion rate and there is less side reaction, thereby improving the purity of the product, the yield is guaranteed. Furthermore, to the sulfonamide pyridine source, the production cost is reduced, has larger the value of industrial production. (by machine translation)
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Paragraph 0049; 0050; 0051; 0052; 0053
(2016/10/07)
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- The in situ generation and reactive quench of diazonium compounds in the synthesis of azo compounds in microreactors
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In this paper, a micro-fluidic optimized process for the continuous flow synthesis of azo compounds is presented. The continuous flow synthesis of Sudan II azo dye was used as a model reaction for the study. At found optimal azo coupling reaction temperature and pH an investigation of the optimum flow rates of the reactants for the diazotization and azo coupling reactions in Little Things Factory-MS microreactors was performed. A conversion of 98% was achieved in approximately 2.4 minutes and a small library of azo compounds was thus generated under these reaction conditions from couplers with aminated or hydroxylated aromatic systems. The scaled up synthesis of these compounds in PTFE tubing (i.d. 1.5 mm) was also investigated, where good reaction conversions ranging between 66-91% were attained.
- Akwi, Faith M.,Watts, Paul
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p. 1987 - 2004
(2016/10/05)
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- Ultrafast Spectroscopy of Hydroxy-Substituted Azobenzenes in Water
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Ultrafast UV/Vis pump/probe experiments on ortho-, meta- and para-hydroxy-substituted azobenzenes (HO-ABs), as well as for sulfasalazine, an AB-based drug, were performed in aqueous solution. For meta-HO-AB, AB-like isomerisation behaviour can be observed, whereas, for ortho-HO-AB, fast proton transfer occurs, resulting in an excited keto species. For para-HO-AB, considerable keto/enol tautomerism proceeds in the ground state, so after excitation the trans-keto species isomerises into the cis form. Aided by TD-DFT calculations, insight is provided into different deactivation pathways for HO-AB, and reveals the role of hydroxy groups in the photochemistry of ABs, as well as their acetylation regarding sulfasalazine. Hydroxy groups are position-specific substituents for AB, which allow tuning of the timescale of thermal relaxation, as well as the amount and contribution of the keto species to photochemical processes.
- Steinwand, Sabrina,Halbritter, Thomas,Rast?dter, Dominique,Ortiz-Sánchez, Juan Manuel,Burghardt, Irene,Heckel, Alexander,Wachtveitl, Josef
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p. 15720 - 15731
(2015/11/03)
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- High molecular weight prodrug derivatives of antiinflammatory drugs
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Compounds of the formula 1, PS - O - A - (CH2)n- B - D (1), wherein PS-O represents an alkoxide residue of any of the free hydroxy groups of a polysaccharide (PS-OH) compound with molecular weight (Mw) of from 40,000 to 5,000,000 selected from dextran, carboxymethyl dextran, diethylaminoethyl dextran, starch, hydroxyet-hyl starch, alginates, glycogen, pullullan, agarose, cellulose, chitosan, chitin and carrageenan,A is a carbonyl group or absent,n is zero or a positive integer from 1 to 14,B is oxygen, a carbonyl group, NR wherein R is hydrogen or lower alkyl, or B is absent, and, D is (i) a group of the formula:, R1 - CO - (11), wherein R1-CO- represents the acyl residue of a carboxylic acid drug (R1-COOH) used in the treatment of inflammatory disorders; or (ii) a group of the formula:, R2 - O - (12), wherein R2-O- refers to the C-21 alkoxide residue of a known antiinflammatory steroid (R2-OH) or an alkoxide residue of any other drug or medicament containing a hydroxy functional group used in the treatment of inflammatory disorders; with the proviso that when A is absent, n is 0, and B is absent, then R1-CO- is different from the acyl residue of acetylsalicylic acid;, and non-toxic pharmaceutically acceptable acid addition salts thereof;, and non-toxic pharmaceutically acceptable cation salts thereof. Such compounds are biolabile prodrugs providing controlled release and prolonged duration of action of the parent active antiinflamma-tory agents locally at the administration site after intra-articular, intra-muscular, subcutaneous or extra-dural application while at the same time being highly stable in aqueous solution in the pH range 3--5. After oral administration of such prodrugs the parent drug is liberated selectively in the terminal ileum and the colon over an extended period of time.
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