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Ring transformations of heterocyclic compounds. XVI. Spiro[cyclohexadiene-dihydroacridines]. A novel class of spirodihydroacridines by ring transformation of pyrylium salts with 9-methylacridine and its quaternary salts

✍ Scribed by Thomas Zimmermann; Ulrich Abram; Klaus Schmidt

Publisher
Journal of Heterocyclic Chemistry
Year
1998
Tongue
English
Weight
501 KB
Volume
35
Category
Article
ISSN
0022-152X

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✦ Synopsis

Abstract

2,4,6‐Triarylpyrylium salts 1 react with the in situ generated anhydrobase of 9,10‐dimethylacridinium methosulfate (2a) in the presence of anhydrous sodium acetate in ethanol by a 2,5‐[C~4~+C~2~] pyrylium ring transformation to give the hitherto unknown 6‐aroyl‐3,5‐diaryl‐10′‐methylspiro[cyclohexa‐2,4‐diene‐1,9′‐9′,10′‐dihydro‐acridines] 3. When the pyrylium perchlorate 1a is treated under the same conditions with the N‐ethyl, N‐allyl or N‐benzyl substituted acridinium salts 2b‐d a dealkylation of these salts occurs and the N‐unsubstituted spiro[cyclohexadiene‐dihydroacridine] 4a is formed. The same compounds 4 can also be obtained by transformation of the pyrylium salts 1 with 9‐methylacridine (7) and triefhylamine/acetic acid in ethanol. Structure elucidation is performed by an X‐ray crystal structure determination of the spiro[cyclohexadiene‐dihydroacridine] 3a. Spectroscopic data of the transformation products and their mode of formation are discussed.

📜 SIMILAR VOLUMES

Ring transformations of heterocyclic com
Ring transformations of heterocyclic compounds. XX Benzo-fused spiro[cyclohexadiene-dihydroindoles] by ring transformation of pyrylium salts with anhydrobases of benzo[e]- and benzo[g]indolium salts
✍ Thomas Zimmermann 📂 Article 📅 2000 🏛 Journal of Heterocyclic Chemistry 🌐 English ⚖ 366 KB

## Abstract The diastereoselective synthesis of 6‐aroyl‐3,5‐diarylspiro[cyclohexa‐2,4‐diene‐1,2′2′,3′‐dihydro‐1′__H__‐benzo[e]indoles] **6** and ‐benzo[__g__]indoles] **7** from 2,4,6‐triarylpyrylium perchlorates **1** and __in situ__ generated 2‐methylene‐2,3‐dihydro‐1__H__‐benzo[__e__]indoles **3

Ring transformations of heterocyclic com
Ring transformations of heterocyclic compounds. XVIII . Spiro[cyclohexadiene-indolines] with three stereocenters from pyrylium salts and chiral methyleneindolines — an example of a high diastereoselective ring transformation
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## Abstract The diastereoselective synthesis of 6‐aroyl‐3,5‐diarylspiro[cyclohexa‐2,4‐diene‐1,2′‐indolines] 4 possessing three stereocenters from 2,4,6‐triarylpyrylium perchlorates 1 and chiral methyleneindolines 3 (generated __in situ__ by deprotonation of the corresponding 3__H__‐indolium perchlo

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## Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable v