Rearrangement of oxazolo[3,2-a]pyridines as an approach of synthesizing aza[3.3.2]cyclazines
摘要:
[GRAPHICS]5-Methyloxazolo[3,2-a]pyridinium salts were shown to react with (methylamino)acetaldehyde dimethyl acetal leading to the formation of functionalized 5-aminoindolizines, which in turn are capable of closing the pyrimidine ring in acidic media forming aza[3.3.2] cyclazines.
在这封信中,我们报告了我们为优化反应条件而进行的努力,并探讨了从恶唑并[3,2- a ]吡啶鎓盐和不同的胺类化合物制备5-氨基吲哚嗪的范围和局限性,以评估其用于组合文库的效用建造。因此,通过施加微波加热,乙腈作为溶剂和DMAP作为附加碱,我们能够将胺的量减少到1.1当量。此外,我们观察到只有空间需求有限的脂族仲胺才能提供所需的化合物。
2-Aryloxazolo[3,2-a]pyridinium perchlorate, 1a, and its 5-methyl homologue, 1b, undergo quite different ring transformations when reacting with piperidine. For 1a the opening of the pyridine fragment occurs with formation of the isomeric aminobutadienes 2 [with (1E,3E)-configuration] or 3 [(1E,3Z)-isomer], depending on the temperature, whereas 1b undergoes an unexpected recyclization of the oxazolium
Synthesis of 5-alkoxyindolizines from oxazolo[3,2-a]pyridinium salts
作者:Eugene V. Babaev、Andrey V. Efimov、Alexander A. Tsisevich、Aleksandra A. Nevskaya、Victor B. Rybakov
DOI:10.1016/j.mencom.2007.03.027
日期:2007.3
The indolizine ring is isomeric and isostructural to indole, and substituted indolizines are frequently prepared as bioisosters of biologically active indole derivatives. A well-known class of psychotropic indole compounds (e.g., psillocine, psylocibine and pindolole) belongs to the family of 5-hydroxy(alkoxy)indoles. An isostructural class of indolizines bearing 5-OR group (A in Scheme 1) may serve
Heterocycles containing a bridge nitrogen atom. 11. Recyclization of 5-methyloxazolo[3,2-apyridinium cation under the action of nucleophiles containing NH2 group. Crystal structure of 3-(p-nitrophenyl)-1,4-dihydropyrido-[2,1-c]-as-triazinium perchlorate
作者:E. V. Babaev、A. V. Efimov、V. B. Rybakov、S. G. Zhukov
DOI:10.1007/bf02319339
日期:1999.4
Heterocycles with a bridged nitrogen atom. 12. Recyclization of 5-methyloxazolo[3,2-a]pyridinium cation in the presence of acetylacetone. Crystal structure of 1-acetyl-2,5-dimethylindolizine
作者:E. V. Babaev、A. V. Efimov、B. V. Rybakov、S. G. Zhukov
DOI:10.1007/bf02256873
日期:2000.3
Heterocycles with a bridging nitrogen atom. 9. Recyclization of an oxazole fragment to a pyrrole fragment. Synthesis and crystal structure of 5-hexamethylenimino-2-p-nitrophenylindolyzine
作者:E. V. Babaev、A. V. Efimov、S. G. Zhukov、V. B. Rybakov