Synthesis of 4-Trifluoromethylpyrimido[4,5-c]pyridazine-5,7-diones from Uracils
摘要:
The reaction of 6-hydrazinouracils (1) with 3-aryl-1,1,1-trifluoropropane-2,3-dione monohydrates (2) in refluxing ethanol in the presence of p-toluenesulfonic acid gave regioselectively 3-aryl-4-trifluoromethyl-5,6,7,8-tetrahydropyrimido[4,5-c]pyridazine-5,7-diones (4a-e) in moderate yields. The location of a trifluoromethyl group at the C4 position was elucidated on the basis of the chemical transformation of the derivatives.
A facile synthesis of fluorine-containing heterocycles - use of 1,1,1-trifluoro-2-alkanones as a convenient synthetic intermediate
作者:Yasuhiro Kamitori
DOI:10.1002/jhet.5570380339
日期:2001.5
3-alkanediones 2 easily obtainable from various aldehyde dialkylhydrazones were reacted with several diamines to afford trifluoromethylquinoxalines 3 and trifluoromethylpyrazines 4 in good yields. With the use of aldehydes and aqueous ammonia instead of diamines, diketones 2 were successfully converted to the corresponding 4-trifluoromethylimidazoles 5 in satisfactory yields.
Hydrogen-Bonding Ability of Noyori–Ikariya Catalysts Enables Stereoselective Access to CF<sub>3</sub>-Substituted <i>syn</i>-1,2-Diols via Dynamic Kinetic Resolution
vinyl, and alkylketones are tolerated, delivering products with ≥95% ee and ≥87:13 syn/anti. This methodology offers rapid access to stereopure bioactive molecules. Furthermore, DFT calculations for three types of Noyori–Ikariya ruthenium catalysts were performed to show their general ability of directing stereoselectivity via the hydrogen bond acceptor SO2 region and CH/π interactions.
立体纯CF 3取代的顺式-1,2-二醇通过HCO 2 H/Et 3 N中相应外消旋α-羟基酮的还原动态动力学拆分来制备。 (Het)芳基、苄基、乙烯基和烷基酮是可耐受的,提供 ≥95% ee 和 ≥87:13 syn / anti的产品。这种方法可以快速获得立体纯的生物活性分子。此外,对三种类型的Noyori-Ikariya钌催化剂进行了DFT计算,以显示它们通过氢键受体SO 2区域和CH/π相互作用引导立体选择性的一般能力。
A Convenient Synthesis of 4-Trifluoromethylimidazol-1-ols
作者:Yasuhiro Kamitori
DOI:10.3987/com-99-8729
日期:——
1,1,1-Trifluoroalkane-2,3-dione 3-oximes easily obtainable from aldehyde dialkylhydrazones were reacted with aldehydes in: the presence of ammonium acetate followed by treatment with 1N HCl affording 4-trifluofomethylimidazol-1-ols in good yields.
A Convenient Synthesis of 4,5-Bis(trifluoromethyl)-pyridazines
作者:Yasuhiro Kamitori、Masaru Hojo、Tatsuya Yoshioka
DOI:10.3987/com-98-8301
日期:——
Acid catalyzed self condensation of 3-hydrazono-1,1,1-trifluoroalkan-2-ones (2) prepared from 1,1,1-trifluoroalkan-2,3-diones (1) and 100% hydrazine hydrate afforded 4,5-bis(trifluoromethyl)pyridazines (3) in satisfactory yields.