Synthesis and NMR spectroscopy investigations of functionalized 8,8,10-trimethyl-4-phenyl-7,8-dihydro-2H,6H-pyrano[3,2-g]chromene-2,6-diones and their spirothiadiazole derivatives
摘要:
New functionalized derivatives of 8,8,10-trimethyl-4-phenyl-7,8-dihydro-2H,6H-pyrano[3,2-g]-chromene-2,6-dione - analogues of the natural compound graveolone - possessing hydrazine, hydroxylamine, and thiosemicarbazide residues were synthesized and their reactions with acetic anhydride were studied. The structure of the obtained compounds was confirmed by NMR spectroscopy.
Unexpected but prominent imines formation in Beckmann rearrangement of (spiro)pyranocoumarin oximes
作者:Igor V. Krasylov、Viktoriia S. Moskvina、Volodymyr P. Khilya
DOI:10.1016/j.tetlet.2023.154747
日期:2023.10
paper presents the successful implementation of Beckmannrearrangement on a series of (spiro)pyranocoumarin oximes in polyphosphoric acid (PPA) medium. The method demonstrated excellent proficiency in the synthesis of unexpected imines as major products and amides as minor products. The labeled 15NH2OH·HCl control experiment yielded oxime and rearrangement products that incorporated the 15N label. Furthermore
本文介绍了一系列(螺)吡喃香豆素肟在多磷酸(PPA)介质中成功实施贝克曼重排。该方法在合成作为主要产物的意想不到的亚胺和作为次要产物的酰胺方面表现出出色的熟练程度。标记的15 NH 2 OH·HCl对照实验产生了并入15 N标记的肟和重排产物。此外,我们还提出了一种可能的重新安排机制。NMR 光谱数据(HMBC 和15 N NMR 相关)证实了合成产物的结构。这些发现为构建在合成有机化学中具有多种应用的复杂亚胺提供了一种新的有效方法。