Construction of Highly Substituted Nitroaromatic Systems by Cyclocondensation. Part II. Conversion of 4-nitro-3-oxobutyrate to 3-nitrosalicylates
作者:Rudolf O. Duthaler
DOI:10.1002/hlca.19830660821
日期:1983.12.14
The base-catalyzed reaction of 4-nitro-3-oxobutyrate (6) with acetylacetone (8Scheme 3), formylacetone (13, Scheme 4), formylcyclohexanone (31, Scheme 5), 2,4-dioxopentanoates 39 and 40(Scheme 6), and 2,4,6-heptanetrione (2, Scheme 7) affords substituted 3-nitrosalicylates, products of a double aldol condensation. With unsymmetrical dicarbonyl compounds both regioisomers are formed. High selectivity
4-硝基-3-氧丁酸乙酯的碱催化反应(6)与乙酰丙酮(8方案3),formylacetone(13,方案4),formylcyclohexanone(31,方案5),2,4- dioxopentanoates 39和40 (方案6)和2,4,6-庚烷三酮(2,流程7)提供取代的3-硝基水杨酸酯,为双羟醛缩合的产物。对于不对称的二羰基化合物,两种区域异构体均形成。在β-酮醛13和31的情况下发现了较高的选择性,并优选添加了NO 2取代的碳为醛羰基。这些环缩合的主要产物都是新化合物,它们的分离产率为20%至80%。用β-烷氧基-和β-氯-乙烯基酮(23、25和26)以及用醛固酮24的转化不太成功,其中缩合产物以非常低的产率形成(方案4)。