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Novel 1,2,3,4‐Tetrahydroquinazolinones via Reaction of 2‐Amino‐N‐substituted Benzamides and Dimethyl Acetylenedicarboxylate 下载免费PDF全文
Semiramis Nahavandian Sadegh Allameh Mina Saeedi Shirin Ansari Mohammad Mahdavi Alireza Foroumadi Abbas Shafiee 《Helvetica chimica acta》2015,98(7):1028-1033
Reaction of 2‐amino‐N‐substituted benzamides and dimethyl acetylenedicarboxylate (DMAD) in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in H2O at room temperature led to the formation of novel 1,2,3,4‐tetrahydroquinazolinones. 相似文献
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Abstract Selective methods for conversion of thionoesters or thiono-lactones to the corresponding ordinary esters or lactones through replacement of sulfur by oxygen are generally lacking, apart from the long known reaction using aqueous silver nitrate1 and related processes with lead1 or mercury2 carboxylates. Our recent preparation of bicyclic thionolactone 1 3 affords a convenient substrate for examination of possible reagents for this transformation. A particularly useful property of 1 is that tetrahedral intermediates 2 and 3, formed on nucleophilic addition of Nu? to 1, have a stereoelectronically favored3,4 pathway for cleavage of the lactone bridge. Such cleavage in 1 is effectively irreversible, since it will be quickly followed by inversion to the stable diequatorial conformer of cis-3-hydroxycyclohexaneacetic acid (4) or an appropriate derivative, depending on the specific nature of Nu?. This feature makes 1 a sensitive test of methods for replacement of sulfur by oxygen without competing rupture of the lactone ring. 相似文献
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