- Preparation method of letrozole
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To the method, a continuous flow chemical technology is adopted to prepare the key intermediate, and the temperature of the reaction is accurately controlled. The content of triazole isomeric impurities 4 - [α - (4 - cyanophenyl) -1 - (1, 3, 4 - triazolyl) methyl] - benzonitrile is reduced, so that repeated recrystallization is avoided, the yield is improved, the total yield is 44% more than 67%, and the cost is saved.
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Paragraph 0032-0033; 0035-0036; 0038-0039; 0040-0041
(2021/11/10)
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- Preparation method of letrozole
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The invention provides a preparation method of letrozole (6). The preparation method comprises the following steps: reacting a compound (1) with a compound (3) under the effect of an alkaline matter; performing a bromination reaction of the compound (3) to obtain a compound (4); condensing the compound (4) and 4-amino-1,2,4-triazole (5); and performing diazotization to remove the amino to obtain letrozole (6). According to the method provided by the invention, the route is simple; the cheap and easily available p-chlorobenzonitrile and p-tolunitrile are adopted as starting raw materials, and the target product letrozole is obtained through 3 steps of reactions in total; and the preparation method has the advantages of mild reaction conditions, simple and convenient operation, high yield, good chemical selectivity and low production cost, is suitable for industrial production and brings relatively great practical application value and social economic benefits.
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- Synthesis and structure-activity relationship of 1- and 2-substituted-1,2,3-triazole letrozole-based analogues as aromatase inhibitors
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A series of bis- and mono-benzonitrile or phenyl analogues of letrozole 1, bearing (1,2,3 and 1,2,5)-triazole or imidazole, were synthesized and screened for their anti-aromatase activities. The unsubstituted 1,2,3-triazole 10a derivative displayed inhibitory activity comparable with that of the aromatase inhibitor, letrozole 1. Compound 10a, bearing a 1,2,3-triazole, is also 10000-times more tightly binding than the corresponding analogue 25 bearing a 1,2,5-triazole, which confirms the importance of a nitrogen atom at position 3 or 4 of the 5-membered ring needed for high activity. The effect on human epithelial adrenocortical carcinoma cell line (H295R) proliferation was also evaluated. The compound 10j (IC50 = 4.64 μM), a letrozole 1 analogue bearing para-cyanophenoxymethylene-1,2,3-triazole decreased proliferation rates of H295R cells by 76 and 99% in 24 and 72 h respectively. Computer calculations, using quantum ab initio structures, suggest a possible correlation between anti-aromatase activity and the distance between the nitrogen in position 3 or 4 of triazole nitrogen and the cyano group nitrogen.
- Doiron, Jeremie,Soultan, Al Haliffa,Richard, Ryan,Toure, Mamadou Mansour,Picot, Nadia,Richard, Remi,Cuperlovic-Culf, Miroslava,Robichaud, Gilles A.,Touaibia, Mohamed
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experimental part
p. 4010 - 4024
(2011/10/30)
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- Letrozole production process
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Provided is a method for preparing letrozole, which includes reacting an activated bis-(4-cyanophenyl)-methane with a triazole to produce letrozole, and, optionally, purifying the letrozole. Also provided are highly pure letrozole, and a method of purifying letrozole, which method includes precipitating letrozole, e.g., by selective precipitation from a reaction mixture and/or by subjecting the letrozole to one or more crystallizations.
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Page/Page column 7
(2008/06/13)
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- A METHOD OF MANUFACTURE OF LETROZOLE
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A novel and convenient method of manufacture of letrozole of formula (I) is described. Letrozole is an aromatase inhibitor drug used in the treatment of postmenopausal breast cancer.
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Page/Page column 9
(2008/06/13)
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