- Synthesis of Isoxazole- And Oxazole-4-carboxylic Acids Derivatives by Controlled Isoxazole-Azirine-Isoxazole/Oxazole Isomerization
-
The first synthesis of isoxazole-4-carboxylic acid derivatives by domino isoxazole-isoxazole isomerization is reported. Fe(II)-catalyzed isomerization of 4-acyl-5-methoxy-/5-aminoisoxazoles (dioxane, 105 °C) leads to the formation of isoxazole-4-carboxylic esters and amides in good yields. 4-Formyl-5-methoxyisoxazoles give methyl oxazole-4-carboxylates under the same reaction conditions. Fe(II)-catalyzed isomerization of 4-acyl-5-methoxyisoxazoles under milder conditions (MeCN, 50 °C) allows the preparation of transient 2-acyl-2-(methoxycarbonyl)-2H-azirines. The azirines isomerize quantitatively either into isoxazoles under catalytic conditions (dioxane, 105 °C) or into oxazoles under noncatalytic thermolysis (o-dichlorobenzene, 170 °C). The mechanism of the isomerization and dependence of the reaction routes on substituents at starting isoxazole core and reaction conditions are discussed on the basis of DFT calculations.
- Serebryannikova, Anna V.,Galenko, Ekaterina E.,Novikov, Mikhail S.,Khlebnikov, Alexander F.
-
p. 15567 - 15577
(2019/11/16)
-
- Substituted N - ((1 °, 3° - [...] - 4° - yl) - methyl) - 4 - benzoyl piperidine compound and use thereof
-
The invention discloses a substituted N-((1', 3'-azole-4'-yl)-methyl)-4-benzoyl-hexahydropyridine compound represented by formula I, a preparation method thereof, and applications of the substituted N-((1', 3'-oxazole-4'-yl)-methyl)-4-benzoyl-hexahydropyridine compound in preparation of antituberculous drugs. The substituted N-((1', 3'-azole-4'-yl)-methyl)-4-benzoyl-hexahydropyridine compound possesses activity on mycobacterium tuberculosis-susceptible strains, and also possesses activity on strains with tolerance on traditional first-line antituberculous drugs such as isoniazide and rifampicin, and is a novel mycobacterium tuberculosis resistant compound with a promising application prospect.
- -
-
Paragraph 0088; 0089; 0090; 0110; 0111; 0112
(2017/04/29)
-
- Discovery of the disubstituted oxazole analogues as a novel class anti-tuberculotic agents against MDR- and XDR-MTB
-
A high-throughput screening effort on 45,000 compounds resulted in the discovery of a disubstituted oxazole as a new structural class inhibitor of Mycobacterium tuberculosis (Mtb). In order to improve the activity and investigate the SAR of this scaffold, a series of disubstituted azole analogues have been designed and synthesized. The newly synthesized compounds 1a-y were evaluated for their in vitro anti-TB activity versus replicating, multi- and extensive drug resistant Mtb strains. All the compounds, except 1o, 1p and 1q, showed potent anti-TB activity with MIC of 1-64 mg/L. The test of broad spectrum panel revealed that this series are specific to Mtb. The cytotoxicity assessment indicated that the compounds were not cytotoxic against HEK 293 cells. The compounds could have a novel mechanism to anti-Mtb as they can inhibit drug sensitive and drug resistant Mtb.
- Li, Dongsheng,Gao, Nana,Zhu, Ningyu,Lin, Yuan,Li, Yan,Chen, Minghua,You, Xuefu,Lu, Yu,Wan, Kanglin,Jiang, Jian-Dong,Jiang, Wei,Si, Shuyi
-
supporting information
p. 5178 - 5181
(2015/11/09)
-
- A direct synthesis of oxazoles from aldehydes
-
An expedient method for the direct conversion of aldehydes to 2,4-disubstituted oxazoles is presented. The method relies on the oxidation of an oxazolidine formed from the condensation of serine with an aldehyde and proceeds through a 2,5-dihydrooxazole intermediate. In contrast to standard methods that start from carboxylic acids, the use of aldehydes as starting materials does not require intermediate purification and affords the oxazoles under relatively mild conditions.
- Graham, Thomas H.
-
supporting information; experimental part
p. 3614 - 3617
(2010/11/17)
-