- An insight into the controllable synthesis of Cd(ii) complexes with a new multifunctional ligand and its application in dye-sensitized solar cells and luminescence properties
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Based on a new design of 4-cyanobenzyl-based 1,2,4-triazole ligand 4-(1,2,4-triazolylmethyl) cyanobenzene (TMCB), a series of cadmium complexes 1-5′ from a mononuclear to three-dimensional (3D) structure have been synthesized through hydro(solvo)thermal reactions; they were generally formulated as [Cd(TMCBA)2]n (1), [Cd(TMCB)(1,4-bda)(H2O)]n (2), {[Cd2(TMCB)4(1,4-bda)2(H2O)2]n·3H2O}n (3), {[Cd(TMCB)4(H2O)2]·(NO3)2·(H2O)2}n (4), [Cd1.5(1,4-bda)1.5(DMF)2]2n (5) and [Cd1.5(1,4-bda)1.5(DMF)2]2n (5′) (TMCBA = 4-(1,2,4-triazolylmethyl) benzoic acid, which is formed from the hydrolysis of TMCB; 1,4-H2bda = 1,4-benzenedicarboxylic acid; the difference between two genuine supramolecular isomers of 5 and 5′ is the use of TMCB as the additive agent for the reaction). Complexes 1-5′ exhibit tunable luminescence with emission maxima containing deep blue, blue, light blue, green and deep green region at 298 K or 77 K in both different solvents (polarity: DMSO > CH3OH > CHCl3) and solid state. Interestingly, the good thermal stability accompanied by their compensated adsorption to ruthenium complex N719 in the region of low wavelength, enabled 1 and 4 to serve as co-sensitizers in combination with N719 in dye sensitized solar cells (DSSCs). After co-sensitization with N719, the overall conversion efficiency of 1 and 4 were found to be 7.68% and 6.85%, which are 40.40% and 25.23% higher than that for DSSCs only sensitized by N719 (5.47%) under the same conditions, respectively. The improvement in efficiency is attributed to the fact that complexes 1 and 4 overcome the deficiency of N719 absorption in the low wavelength region of ultraviolet and blue-violet, offset competitive visible light absorption of I3- and reduce charge recombination due to the formation of an effective cover layer of the dye molecules on the TiO2 surface. As a result, the synthesized complexes are promising candidates as co-adsorbents and co-sensitizers for highly efficient DSSCs.
- Gao, Song,Fan, Rui Qing,Wang, Xin Ming,Qiang, Liang Sheng,Wei, Li Guo,Wang, Ping,Zhang, Hui Jie,Yang, Yu Lin,Wang, Yu Lei
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Read Online
- A “universal” catalyst for aerobic oxidations to synthesize (hetero)aromatic aldehydes, ketones, esters, acids, nitriles, and amides
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Functionalized (hetero)aromatic compounds are indispensable chemicals widely used in basic and applied sciences. Among these, especially aromatic aldehydes, ketones, carboxylic acids, esters, nitriles, and amides represent valuable fine and bulk chemicals, which are used in chemical, pharmaceutical, agrochemical, and material industries. For their synthesis, catalytic aerobic oxidation of alcohols constitutes a green, sustainable, and cost-effective process, which should ideally make use of active and selective 3D metals. Here, we report the preparation of graphitic layers encapsulated in Co-nanoparticles by pyrolysis of cobalt-piperazine-tartaric acid complex on carbon as a most general oxidation catalyst. This unique material allows for the synthesis of simple, functionalized, and structurally diverse (hetero)aromatic aldehydes, ketones, carboxylic acids, esters, nitriles, and amides from alcohols in excellent yields in the presence of air.
- Bartling, Stephan,Beller, Matthias,Chandrashekhar, Vishwas G.,Jagadeesh, Rajenahally V.,Rabeah, Jabor,Rockstroh, Nils,Senthamarai, Thirusangumurugan
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supporting information
p. 508 - 531
(2022/02/11)
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- Taming Ambident Triazole Anions: Regioselective Ion Pairing Catalyzes Direct N-Alkylation with Atypical Regioselectivity
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Controlling the regioselectivity of ambident nucleophiles toward alkylating agents is a fundamental problem in heterocyclic chemistry. Unsubstituted triazoles are particularly challenging, often requiring inefficient stepwise protection-deprotection strategies and prefunctionalization protocols. Herein we report on the alkylation of archetypal ambident 1,2,4-triazole, 1,2,3-triazole, and their anions, analyzed by in situ 1H/19F NMR, kinetic modeling, diffusion-ordered NMR spectroscopy, X-ray crystallography, highly correlated coupled-cluster computations [CCSD(T)-F12, DF-LCCSD(T)-F12, DLPNO-CCSD(T)], and Marcus theory. The resulting mechanistic insights allow design of an organocatalytic methodology for ambident control in the direct N-alkylation of unsubstituted triazole anions. Amidinium and guanidinium receptors are shown to act as strongly coordinating phase-transfer organocatalysts, shuttling triazolate anions into solution. The intimate ion pairs formed in solution retain the reactivity of liberated triazole anions but, by virtue of highly regioselective ion pairing, exhibit alkylation selectivities that are completely inverted (1,2,4-triazole) or substantially enhanced (1,2,3-triazole) compared to the parent anions. The methodology allows direct access to 4-alkyl-1,2,4-triazoles (rr up to 94:6) and 1-alkyl-1,2,3-triazoles (rr up to 99:1) in one step. Regioselective ion pairing acts in effect as a noncovalent in situ protection mechanism, a concept that may have broader application in the control of ambident systems.
- Dale, Harvey J.A.,Hodges, George R.,Lloyd-Jones, Guy C.
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p. 7181 - 7193
(2019/05/10)
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- Method for continuously preparing letrozole intermediate 4-((1H-1,2,4-tri-1-zole)methyl) benzonitrile
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The invention relates to a method for continuously preparing letrozole intermediate 4-((1H-1,2,4-tri-1-zole)methyl) benzonitrile (I).The problems that in the process of producing a compound (I) in the prior art, the reactant p-cyanobenzyl chloride is low in conversion rate, and a product is difficult to separate are mainly solved.The continuous coupling process of separating and purifying the compound (I) is achieved by adopting reacting, salifying and filtering.The reaction product is continuously separated from a system in time, the compound (I) can be produced continuously, easily and fast with low energy consumption, the yield of the obtained reaction product compound (I) is larger than 80%, and the chemical purity is larger than 98%.
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Paragraph 0023; 0024; 0025; 0005
(2016/11/09)
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- A base-induced ring-opening process of 2-substituted-1,3,4-oxadiazoles for the generation of nitriles at room temperature
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A novel base-catalysed 1,3,4-oxadiazole fragmentation for the synthesis of nitriles at room temperature has been developed. This reaction is performed under transition-metal-free conditions, and provides a new ring cleavage reaction of 1,3,4-oxadiazoles in organic synthesis.
- Lu, Guo-Ping,Lin, Ya-Mei
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p. 371 - 374
(2014/07/08)
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- PURE INTERMEDIATE
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The present invention relates to an improved process for the preparation of Letrozole (I) and its synthetic intermediate 4-[(1-(1,2,4-triazolyl)methyl]benzonitrile (III). In particular, it relates to a process to prepare Letrozole and its intermediate (III) substantially free from regioisomeric impurities. The present invention further relates to acid addition salts of 4-[(1-(1,2,4-triazolyl)methyl]benzonitrile (III) such as the oxalate salt, and also to Letrozole (I), the intermediate (III) and salts thereof preparable by the processes of the present invention.
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Page/Page column 40-41
(2012/03/26)
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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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- REGIOSELECTIVE SYNTHESIS OF LETROZOLE
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The present invention relates to an improved process for the preparation of letrozole (I) and its pharmaceutically acceptable salts, to compositions comprising letrozole or a pharmaceutically acceptable salt thereof, and to uses of such compositions. In particular it relates to a process and to novel intermediates for preparing letrozole and its salts substantially free from regioisomeric impurities.
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Page/Page column 19
(2010/12/31)
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- Process for the Preparation of Letrozole
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The present invention relates to the process for the preparation of Letrozole free from its regioisomer (7) and other impurities by selective extraction of desired intermediate (3) using suitable solvent and mixture of solvents.
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Page/Page column 6
(2010/08/07)
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- AN IMPROVED PROCESS FOR PREPARATION OF LETROZOLE AND ITS INTERMEDIATES
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The present invention relates to an improved process for preparation of the non-steroidal aromatase inhibitor drug, Letrozole of formula (I) and its intermediates, 4-[1-(1,2,4-triazolyl) methyl]-benzonitrile of formula (IV) and 4-[1-(1,2,4-triazolyl) methyl]-benzonitrile hydrochloride of formula (VII), all having a purity of ≥99%, which is simple, convenient, economical, does not use hazardous chemicals and industrially viable.
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Page/Page column 39-41
(2009/07/03)
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- SYNTHESIS OF 4-[1-(4-CYANO PHENYL)-(1,2,4-TR1AZOL-1-YL)METHYL] BENZONITRILE AND 4-[1-(1H-1,2,4-TRIAZOL-1-YL)METHYLENE BENZONITRILE INTERMEDIATE
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The present invention relates to a process for the preparation of 4-[1-(4-cyano phenyl)-1- (1 ,2,4-triazol-1-yl) methyl] benzonitrile (letrozole), substantially free from its isomeric impurity. The preparation involves reaction of 4-[1-(1 H-1 ,2,4-triazol-1-yl)methylene benzonitrile with 4-fluorobenzonitrile in the presence of an organic solvent and a silicon amine. The present invention also relates to a process for the preparation of 4-[1-(1 H- 1 ,2,4-triazol-1-yl)methylene benzonitrile which involves: (a) the reaction of a 4-halomethyl benzonitrile with 1 ,2,4-triazole in the presence of cesium carbonate and an organic solvent to obtain a reaction mass comprising 4-[1-(1 ,2,4-triazole-1-yl)methyl] benzonitrile of formula II; and (b) precipitation of 4-[1-(1 ,2,4-triazole-1-yl)methyl]benzonitrile (II) from the reaction mass using a suitable organic solvent.
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Page/Page column 13-14; 16-17
(2008/06/13)
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- PROCESS FOR THE PREPARATION OF LETROZOLE
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The present invention relates to the process for the preparation of Letrozole free from its regioisomer (7) and other impurities by selective extraction of desired intermediate (3) using suitable solvent and mixture of solvents.
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Page/Page column 9-10
(2008/06/13)
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- PROCESS FOR PREPARING LETROZOLE
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A process for preparing letrozole by reacting p-fluorobenzonitrile with 4[1-(1,2,4- triazolyl)methyl]benzonitrile in the presence of an alkali metal alkoxide, characterised in that it comprises adding : 5 A) simultaneously separate solutions of respectively p-fluorobenzonitrile and 4[1- (1,2,4-triazolyl)methyl]benzonitrile in an aprotic dipolar solvent, or alternatively B) a unique solution of a mixture of p-fluorobenzonitrile and 4[1-(1,2,4- triazolyl)methyl]benzonitrile in an aprotic dipolar solvent, to a solution of said alkali metal alkoxide in the same dipolar aprotic solvent of (A) 10 or (B).
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Page/Page column 7-8
(2010/11/28)
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- Process for the preparation of letrozole
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The invention provides a high-yield process for the preparation of letrozole having a high purity, without the need for removal of the 4-[1-(1,3,4-triazolyl)methyl]benzonitrile impurity at the intermediate stage. The invention also provides a process for the synthesis of letrozole in which formation of the impurity 4-[1-(1,3,4-triazolyl)methyl]benzonitrile during the first stage is minimized. In the process, a 4-(halomethyl)benzonitrile is reacted with a salt of 1H-1,2,4-triazole, reducing the formation of the impurity. Preferably, the preparation is conducted as a one-pot process.
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Page/Page column 6-7; 9
(2010/11/26)
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- Process for producing 4-(1H-1,2,4-triazol-1-ylmethyl)benzonitrile
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The invention discloses an improved process for producing 4-(1H-1,2,4-triazol-1-ylmethyl)benzonitrile of Formula (Structure 2), an intermediate used in the manufacture of 4,4′-[1H-1,2,4-triazol-1-ylmethylene] bisbenzonitrile (Letrozole), the process comprising of reacting salt of 1,2,4-triazole of Formula (Structure 4) with α-halo substituted tolunitrile of Formula (Structure 3) in presence of dimethylformamide, wherein the X represents alkali metals selected from a group of Li, Na, or K, preferably Na and Y represents a halogen group selected from Cl, Br or I, preferably Br.
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Page/Page column 2
(2008/06/13)
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- A METHOD FOR THE SEPARATION OF THE LETROZOLE PRECURSOR 4-‘1-(1,2,4-TRIAZOLYL) METHYL!BENZONITRILE FROM ITS 1,3,4-TRIAZOLYL ISOMER
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A chemical method for the separation of letrozole precursor 4-[1-1,2,4-triazolyl)methyl]benzonitrile of formula (I) from the isomeric unwanted byproduct 4-[1-(1,3,4-triazolyl)methyl]benzonitrile of formula (II) of the reaction in which it is produced, which comprises (a) Preparing an isomeric mixtures of the compounds of formula (I) and (II) by conventional methods. (b) Dissolving the resultant crude isomeric mixture in dichloro methane (or) chloroform. (c) Adding 10-14% isopropylalcohol hydrochloride (IPACHI) to the resulting solution. (d) Adding isopropyl ether to precipitate undesired isomer is hydrochloride form. (e) Filtering off the undesired isomer hydrochloride. (f) Distilling off the filtrate completely. (g) Adding dilute sodium hydroxide solution and dichloromethane to the residue to liberate required isomer base of the formula (I). (h) Evaporating the separated dichloromethane layer and charging hexane or petroleum ether. (i) Centrifuging the resultant product of the formula (I) and washing with hexane or petroleum ether.
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Page/Page column 7-8
(2008/06/13)
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