Singlet oxygen oxidation of substituted furans to 5-hydroxy-2(5H)-furanone
摘要:
The conditions for the regiospecific singlet oxygen oxidation of various 2,4-disubstituted furans 9 to 4-substituted-2 (5H)-furanones 3 are developed. The presence of a C-2 substituent (e.g., trimethylsilyl, tert-butyldimethylsilyl, or tributylstannyl) in 9 is an absolute requirement for the formation of the 4-substituted-5-hydroxy-2(5H)-furanone regioisomer 3. When the C-2 substituent is triethylsilyl (TES) or TBDMS, however, apart from 3, the corresponding 5-trialkylsiloxy derivative 11 is also isolated in a significant amount. These silyl acetals are unexpectedly stable but can be hydrolyzed back to 3 on stirring with dilute acid. The formation of silyl acetals, to our knowledge, has never been reported in the singlet oxygen oxidation of (trialkylsilyl)furan. A plausible mechanism for their formation is proposed. The presence of a catalytic amount of water in the oxidation of 2-(trialkylsilyl)-4-substituted-furans not only eliminates the formation of the silyl acetals but also speeds up the rate of the oxidation process. Moreover, the oxidation can then be carried out at 0-degrees-C instead of at -78-degrees-C. Oxidation of 2-(1-hydroxyalkyl)-4-substituted-furans in the absence of a reducing agent gives little or no sign of 2,5-disubstituted-6-hydroxy-3(2H)-pyranone 23 but instead 26 selectively. Thus, the (1-hydroxy)alkyl group can be utilized as the trialkylsilyl or trialkylstannyl group in dictating the regioselectivity in the singlet oxygen oxidation of substituted furans.
New 5-hydroxy-2-furanone compounds having anti-inflammatory, immunosuppressive and anti-proliferative activity and are useful in treating psoriasis and modifying calcium homeostasis.
新的具有抗炎、免疫抑制和抗增殖活性的5-羟基-2-呋喃酮化合物对治疗牛皮癣和调节钙稳态具有用处。
[EN] 2-AMINO-1,3,4-THIADIAZINE AND 2-AMINO-1,3,4-OXADIAZINE BASED ANTIFUNGAL AGENTS<br/>[FR] AGENTS ANTIFONGIQUES À BASE DE 2-AMINO-1,3,4-THIADIAZINE ET DE 2-AMINO-1,3,4-OXADIAZINE
申请人:F2G LTD
公开号:WO2017009651A1
公开(公告)日:2017-01-19
The invention provides a compound which is a diazine of formula (I) or a tautomer thereof, or a pharmaceutically acceptable salt thereof, for use as an antifungal agent: (I) wherein X, N', C', A and E are as defined herein. The invention also provides a compound of Formula (I) as defined herein.
The discovery of new templates and their subsequent elaboration to clinically useful receptor tyrosine kinase (RTK) inhibitors continues to be an important issue. RTKs are a class of enzymes responsible for the activation of different cellular signal transduction cascades. The majority of the known small molecules RTK inhibitors are ATP-competitive and they are multiple targeted inhibitors. We describe here serotonin derivatives as a new class of multiple targeted RTK inhibitors. In contrast to most other RTK inhibitors they act via a non-ATP-competitive (allosteric) mechanism. Furthermore, they are able to inhibit the proliferation of HUVE cells, fibroblasts and two cancer cell lines. (C) 2010 Elsevier Ltd. All rights reserved.