- A practical and efficient process for the preparation of tazarotene
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We describe an efficient process for the preparation of tazarotene starting from 4,4-dimethyl-6-bromothiochromane S-oxide (9), 2-methyl-3-butyn-2-ol (10), and 6-chloronicotinic acid ethyl ester (8). Our synthetic pathway compares favorably over the previously reported procedures since tazarotene was prepared straightforwardly using cheap reagents and without the employment of hazardous organometallic compounds. The process is based on the use of sulfoxide 9 as key starting material. The C-15 framework of the target was built up by means of two different approaches based on a palladium-mediated coupling reaction. The molecular structure of compound has been confirmed by X-ray crystallography.
- Frigoli, Samuele,Fuganti, Claudio,Malpezzi, Luciana,Serra, Stefano
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- Method for preparing tazarotene without copper iodide
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The invention provides a method for preparing tazarotene without copper iodide. Palladium catalysts and triphenylphosphine are added into specific organic solvents and stirred, replacement in nitrogenis performed, 4, 4-dimethyl thiochroman-6-radical-acetylene, 6-chloro-ethyl nicotinate and acid-binding agents are added to perform reaction. The method is environmentally friendly, the catalysts areeasily recycled, and waste water containing heavy metal is not generated. Compared with the prior art, the method is short in reaction time and reaction temperature. A product prepared by the methodis high in yield and purity and stable in quality.
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Paragraph 0057-0067
(2019/01/14)
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- TAZAROTENE WITH LOW DIMER IMPURITY FOR TREATING ACNE OR PSORIASIS
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The present invention relates to a method of treating acne or psoriasis by topically administering Tazarotene substantially free of dimer impurity of formula 4,4-dimethyl-6-[4-(4,4-dimethylthiochroman-6-yl)-buta-1,3-diynyl]-thiochroman.
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Page/Page column 13
(2016/06/28)
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- PROCESS FOR PREPARATION OF TAZAROTENE
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Disclosed herein is process for preparation of 6-[2-(4,4-dimethylthiochroman-6- yl)ethynyl]nicotinate known as Tazarotene of Formula (I) and its pharmaceutical acceptable salts, wherein said process comprises, reacting 4,4-dimethyl-6- acetylthiochroman with chlorinating reagent to get novel intermediate compound 6- (l,l-dichloroethyl)-4,4-dimethylthiochroman followed by converting the compound 6- (l,l-dichloroethyl)-4,4-dimethylthiochroman to get Tazarotene.
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Page/Page column 12
(2009/10/22)
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- Process for the preparation of tazarotene intermediates and use thereof for the preparation of tazarotene
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The present invention provides a novel intermediate of ethyl 6-[2-(4,4-dimethylthiochroman-6-yl)ethynyl] nicotinate or a pharmaceutically acceptable salt thereof and a process for its preparation. The present invention also provides for the preparation of ethyl 6-[2-(4,4-dimethylthiochroman-6-yl)ethynyl] nicotinate of Formula I or a pharmaceutically acceptable salt thereof using the intermediate.
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Page/Page column 7
(2010/11/28)
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- PROCESS FOR THE PREPARATION OF ACETYLENIC RETINOID
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A process for the preparation of acetylenic retinoid, ethyl-6-[2- (4,4- dimethylthiochroman-6-yl)ethynyl]nicotinate, a compound of formula 1,comprising, (a) cyclizing phenyl-3-methylbut-2-enylsulfide, a compound of formula 6, in presence of an acid selected from sulfuric acid or p-toluenesulfonic acid to yield 4,4-dimethylthiochroman, a compound of formula 2; (b)acetylating the compound of formula 2, to 4,4 -dimethyl-6-acetylthiochroman, a compound of formula 3; (c)(i) reacting the compound of formula 3 with hydrazine;(ii) reacting resultant product of step (i) with iodine; (iii) converting the resultant product of step (ii) to 4,4-dimethyl-6- ethynyl thiochroman, a compound of formula 4 and (d) reacting the compound of formula 4 with ethyl-6-halonicotinate, a compound of formula 5, wherein X is Cl or Br, in presence of cuprous halide, a transition metal and an inorganic base.
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Page/Page column 20-21
(2008/06/13)
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- Process for the preparation of Tazarotene
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Tazarotene is prepared by deoxygenation of the corresponding S-oxide, in turn obtained according to two alternative synthetic pathways.
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Page/Page column 4; 5
(2010/11/23)
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- A process for the preparation of tazarotene
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Tazarotene is prepared by deoxygenation of the corresponding S-oxide, in turn obtained according to two alternative synthetic pathways.
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Page/Page column 6
(2010/11/23)
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- PROCESS FOR THE PREPARATION OF DISUBSTITUTED ACETYLENES BEARING HETEROAROMATIC AND HETEROBICYCLIC GROUPS
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A process for the preparation of a disubstituted acetylene bearing heteroaromatic and heterobicyclic groups of formula I is provided wherein X is S, O, or NR1 wherein R1 is hydrogen or a C1-C6 straight or branched alkyl group; R is hydrogen or a C1-C6 straight or branched alkyl group; A is a substituted or unsubstituted pyridinyl, thienyl, furyl, pyridazinyl, pyrimidinyl or pyrazinyl group; n is 0--4; and B is H2 -COOH, -CH2OH, -CHO or a C1-C6 alkyl acetal derivative, -COR2or a C1-C6 alkyl ketal derivative where R2 is -(CH2),,,CH3 where m is 0-4 or COOR3 wherein R3 is a straight or branched C1-C30 alkyl group, a substituted or unsubstituted C6-C30 aromatic group, a substituted or unsubstituted C3-C30 cycloalkyl, a substituted or unsubstituted C3-C30 cycloalkylalkyl, a substituted or unsubstituted C3-C30 cycloalkenyl, a substituted or unsubstituted C5-C30 aryl, a substituted or unsubstituted C5-C30 arylalkyl, a substituted or unsubstituted C5-C30heteroaryl, a substituted or unsubstituted C3-C30 heterocyclic ring, a substituted or unsubstituted C4-C30 heterocyclylalkyl, a substituted or unsubstituted C6-C30 heteroarylalkyl, the process comprising a Sonogashira coupling reaction between a compound of formula II wherein X and R have the aforestated meanings, with a compound of formula III wherein X' is a halogen and A, n and B have the aforestated meanings, in the presence of a base and a transition metal catalyst and in a polar aprotic solvent.
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Page/Page column 13
(2010/02/15)
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- Disubstituted acetylenes bearing heteroaromatic and heterobicyclic groups having retinoid like activity
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Retinoid-like activity is exhibited by compounds of the formula STR1 where X is S, O, or NR' where R' is hydrogen or lower alkyl; R is hydrogen or lower alkyl; A is pyridyl, thienyl, furyl, pyridazinyl, pyrimidinyl or pyrazinyl; n is 0-4; and B is H, --COOH or a pharmaceutically acceptable salt, ester or amide thereof, --CH2 OH or an ether or ester derivative, or --CHO or an acetal derivative, or --COR1 or a ketal derivative where R1 is --(CH2)m CH3 where m is 0-4, or a pharmaceutically acceptable salt thereof.
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- Disubstituted acetylenes bearing heteroaromatic and heterobicyclic groups having retinoid like activity
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Retinoid-like activity is exhibited by compounds of the formula STR1 where X is S, O, or NR' where R' is hydrogen or lower alkyl; R is hydrogen or lower alkyl; A is pyridyl, thienyl, furyl, pyridazinyl, pyrimidinyl or pyrazinyl; n is 0-2; and B is H, --COOH or a pharmaceutically acceptable salt, ester or amide thereof, --CH2 OH or an ether or ester derivative, or --CHO or an acetal derivative, or --COR1 or a ketal derivative where R1 is --(CH2)m CH3 where m is 0-4, or a pharmaceutically acceptable salt thereof.
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