- PROCESS AND INTERMEDIATE OF LETROZOLE
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The present invention relates to a process for the preparation of Letrozole involving the use of novel intermediate of Formula I.
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Page/Page column 5
(2009/07/18)
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- Synthesis of N-Cyanoazoles
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1-Cyanoimidazole, 1-cyano-2-methylimidazole, 1-cyanobenzimidazole, and 1-cyano-1,2,4-triazole were prepared by reaction of corresponding azoles with cyanogen bromide.Reactions of cyanogen bromide with sodium benzotriazolide and sodium pyridin-2-olate yield 1-cyanobenzotriazole and 2-cyanatopyridine.
- Purygin, P. P.,Pan'kov, S. V.
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p. 865 - 867
(2007/10/03)
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- N-SULFONYLBENZOTRIAZOLES. PART 2. REACTIONS OF 1,1'-SULFONYLDIBENZOTRIAZOLE AND 1-BENZENESULFONYL-1,2,4-TRIAZOLE WITH ALCOHOLS; A NEW APPROACH TO N-ALKYLBENZOTRIAZOLES AND N-ALKYL-1,2,4-TRIAZOLES
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1,1'-Sulfonyldibenzotriazole (3) reacts with sodium alkoxides to give N-alkylbenzotriazoles.With alkanols, benzotriazolium alkyl sulfates are produced. 1-Benzenesulfonyl-1,2,4-triazole with sodium salts of alcohols gives 1-alkyl-1,2,4-triazoles.The mechanisms of these reactions are discussed.
- Katritzky, Alan R.,Zhang, Gui-Fen,Pernak, Juliuzs,Fan, Wei-Qiang
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p. 1253 - 1262
(2007/10/02)
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- Alkylation, Acylation and Silylation of Azoles
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Performing alkylation, acylation and silylation reactions in separate deprotonation and nucleophilic displacement steps allows for better control of reaction conditions and facilitates problem handling in these processes.In the alkylation of azoles the alkylating agents and solvents possess individual reaction capabilities which seem to be approximately additive.Monoalkylation occurs if the sum of the normalized reaction potentials is equal or larger than the pKa value of the azole.Dialkylation is avoided by keeping the sum of the normalized reaction potentials below the pKa value of the alkylazole.The applicability of these principles is demonstrated by the development of effective procedures for the methylation, benzylation, acetylation, methoxycarbonylation and trimethylsilylation of azoles.
- Begtrup, Mikael,Larsen, Peter
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p. 1050 - 1057
(2007/10/02)
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