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Dioxirane oxidation of (Z)-1-thioaurones, (E)-3-arylidene-1-thiochroman-4-ones and (E)-3-arylidene-1-thioflavan-4-ones

✍ Scribed by Waldemar Adam; Dieter Golsch; Lazaros Hadjiarapoglou; Albert Lévai; Csaba Nemes; Tamás Patonay

Book ID
104204719
Publisher
Elsevier Science
Year
1994
Tongue
French
Weight
493 KB
Volume
50
Category
Article
ISSN
0040-4020

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✦ Synopsis

The oxidation of the title compounds $4 and 7 with dimethyldioxirane @MD) afforded the corresponding sulfoxides 2, 5 and 8 and/or sulfones 3, 6 and 9 in good yields (Scheme 1 and 2). Excess diiethyldioxirane gave the sulfones chemoselectively without formation of the epoxides. The epoxidation of the sulfones 6a,b,d to the respective spiroepoxides lOa,b,d required the more reactive methyl(trifluoromethyl)dioxirane (TFD) as oxidant. Previously we have investigated the oxidation of aurones,' 3-aryfidenechromanones2 and 3-arylideneflavanones,' for which dimethyldioxirane proved to be a convenient oxygen transfer reagent in the preparation of aurone epoxides' and trans and cis spiroepoxides from Q-and (Z)-3-arylidenechromanones.r We provided a diasterwselective synthesis of trans,trans spiroepoxides from Q-3-arylideneflavanones both by isolated dimethyldioxirane and methyl(trifluoromethyl)dioxirane~ however, attempted epoxidation of the Q-3-arylideneflavanones with these two dioxiranes afforded instead the 3-aroylflavones and/or 3-aroylflavanones in low yield.) The present paper reports the oxidation of the thio analogues of the abovementioned oxygen heterocycles with the same oxygen transfer reagents. s Q+

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Reaction of E-2-arylidene-1-indanones, Z
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## Abstract 1,3‐Dipolar cycloaddition of __E__‐2‐arylidene‐1‐indanones 1a‐h and Z‐aurones 3a‐c with diazomethane provided __trans__‐spiro‐1‐pyrazolines 2a‐h and 4a‐c, respectively, as sole products. However, the same cycloaddition of Z‐1‐thioaurones 5a‐f afforded a mixture of Z‐α‐methyl‐1‐thioauron

NMR and quantum-chemical study of the st
NMR and quantum-chemical study of the stereochemistry of spiroepoxides obtained by oxidation of (Z)-3-arylidene-1-thioflavan-4-ones
✍ Gábor Tóth; József Kovács; Albert Lévai; Erich Kleinpeter; Andreas Koch 📂 Article 📅 2001 🏛 John Wiley and Sons 🌐 English ⚖ 179 KB

## Abstract Epoxidation of (__Z__)‐3‐arylidene‐1‐thioflavan‐4‐ones (**1**) yielded __trans,cis__ (**2**) and __trans,trans__ (**3**) isomers. The structure and signal assignments were elucidated by extensive application of one‐ and two‐dimensional ^1^H and ^13^C NMR spectroscopy. The conformational