ChemicalBook CAS DataBase List Tenoxicam

Tenoxicam synthesis

8synthesis methods

Product Name:Tenoxicam
CAS Number:59804-37-4
Molecular formula:C13H11N3O4S2
Molecular Weight:337.37

The reaction of methyl 3-hydroxythiophene- 2-carboxylate with PCl5 in refluxing CCl4 gives 3-chlorothiophene-2-carboxylic acid, which by treatment with NaHSO3 and Cu in aqueous alkaline solution at 143 ?C in a pressure vessel is converted into 3- sulfothiophene-2-carboxylic acid. Its esterification with refluxing methanol affords methyl- 3-sulfothiophene-2-carboxylate, which by reaction with refluxing SOCl2 yields methyl- 3-chlorosulfonylthiophene-2-carboxylate. The following condensation with sarcosine ethyl ester in hot CHCl3 gives 3-(N-ethoxycarbonylmethyl- N-methylsulfamoyl)thiophene-2-carboxylate, which is cyclized by treatment with sodium methoxide in refluxing methanol affording 3-ethoxycarbonyl-4-hydroxy-2-methyl-2Hthieno--1,2-thiazine 1,1-dioxide. Finally this compound is condensed with 2-aminopyridine in refluxing toluene

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59804-25-0 Synthesis

METHYL 2-METHYL-4-HYDROXY-2H-THIENO[2,3-E]-1,2-THIAZINE-3-CARBOXYLATE-1,1-DIOXIDE

59804-25-0
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59804-37-4
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Yield:59804-37-4 76.9%

Reaction Conditions:

in 5,5-dimethyl-1,3-cyclohexadiene for 6 h;Reflux;Concentration;

Steps:

1.4 4. tenoxicam
5.4 g of TNXK-3, 300 ml xylene and 1.4g 2-aminopyridine in xylene solution 2.8 ml heating to reflux. After stirring reaction 6 hours, cooling. the majority of the solvent is removed under reduced pressure, cooling, filtering, the filter cake by adding 15 ml in water, adding sodium hydroxide 1 g and methanol 55 ml, heating the solvent, used to decolorize with active carbon, the filtrate is adjusted to PH hydrochloric acid 3, is cooled and is filtered, the filter cake is benzodioxane recrystallized, to get the yellow solid 4.2 g, yield 76.9%.

References:

Jiangxi Yong Tong Technology Co., Ltd.;Liu Zhongchun CN107141308, 2017, A Location in patent:Paragraph 0056-0060; 0066; 0070; 0076; 0080; 0086; 0090

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