Diastereoselective synthesis of fluorinated piperidine quinazoline spirocycles as iNOS selective inhibitors
作者:Chris Walpole、Ziping Liu、Ernest E. Lee、Hua Yang、Fei Zhou、Nicole Mackintosh、Magnus Sjogren、David Taylor、Jinyu Shen、Robert A. Batey
DOI:10.1016/j.tetlet.2012.03.050
日期:2012.6
A diastereoselective synthesis of fluoropiperidine quinazoline spirocycles has been developed through a silyl triflate mediated intermolecular coupling of difluorobenzamidine and racemic N-protected 3-fluoropiperidine dimethyl ketals or piperidones. Combination of the silyl reagents together with Lewis acids (such as BF3 center dot OEt2, ZnCl2, InCl3, etc.) accelerated the coupling reaction to afford the desired fluorospirocycies in good yields (40-83%) and high diastereoselectivity. A ratio of the two diastereoisomers of up to 10:1 in favor of the desired isomer can be achieved. (C) 2012 Published by Elsevier Ltd.
[EN] NOVEL COMPOUNDS<br/>[FR] NOUVEAUX COMPOSES
申请人:ASTRAZENECA AB
公开号:WO2001058867A2
公开(公告)日:2001-08-16
There are provided novel compounds of formula (I) wherein R?1, R2, R3, R4 and R5¿ are as defined in the Specification and optical isomers, racemates and tautomers thereof and pharmaceutically acceptable salts thereof; together with processes for their preparation, compositions containing them and their use in therapy. The compounds are inhibitors of the enzyme nitric oxide synthase.
Effect of acid catalysis on the direct electrophilic fluorination of ketones, ketals, and enamides using Selectfluor™
作者:Jack Liu、Johann Chan、Craig M. Bryant、Petar A. Duspara、Ernest E. Lee、David Powell、Hua Yang、Ziping Liu、Chris Walpole、Edward Roberts、Robert A. Batey
DOI:10.1016/j.tetlet.2012.03.074
日期:2012.6
The fluorination of ketones, ketals, and enamides has been achieved using the electrophilic fluorinating reagent Selectfluor™ (F-TEDA-BF4). For the reactions of ketones and ketals the use of sulfuric acid (0.1 equiv) as an additive was found to facilitate the reaction leading to more rapid product formation. This behavior is analogous to the known effects of acid catalysis on the bromination of ketones
There are provided novel compounds of formula (I) wherein R
1
, R
2
, R
3
, R
4
and R
5
are as defined in the Specification and optical isomers, racemates and tautomers thereof and pharmaceutically acceptable salts thereof; together with processes for their preparation, compositions containing them and their use in therapy. The compounds are inhibitors of the enzyme nitric oxide synthase.