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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
Author(s) -
Zimmermann Thomas,
Abram Ulrich,
Schmidt Klaus
Publication year - 1998
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570350403
Subject(s) - chemistry , ring (chemistry) , perchlorate , acetic acid , medicinal chemistry , anhydrous , alkylation , ethanol , transformation (genetics) , sodium salt , sodium perchlorate , crystal structure , stereochemistry , organic chemistry , ion , inorganic chemistry , catalysis , biochemistry , gene , electrode , electrochemistry
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.