ISSN:
1434-193X
Keywords:
syn-[2.2](1,6)Azulenophane
;
syn-[2.2](4,6)Azulenophane
;
[2.2.2.2](1,6)-Azulenophane
;
[2.2.2.2.2.2](1,6)Azulenophane
;
[2.2.2.2](4,6)Azulenophane
;
Phanes
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A regioselective synthesis of syn-[2.2](1,6)azulenophane (9) and syn-[2.2](4,6)azulenophane (12) is described. Azulenophane 9 is prepared by deprotonation of 1,2-bis(6-methylazulen-1-yl)ethane (5), followed by oxidative coupling of the initially formed dilithium salt 8 with iodine under high-dilution conditions in 17% yield, along with the macrocyclic [2.2.2.2](1,6)azulenophane (10) (3%), and [2.2.2.2.2.2](1,6)azulenophane (11) (1.5%). The azulenophane 12 and the macrocyclic [2.2.2.2](4,6)azulenophane (13) are obtained by coupling of the dianion of 1,2-bis(4-methylazulen-6-yl)ethane (14). The structural assignments of the title compounds are based on their spectral data. Protonation of 9 furnishes the mono- and dications 24 and 25, respectively, of which the first exhibits a charge-transfer band in its electronic spectrum, indicating a transannular interaction between the protonated and unprotonated azulene units. Protonation of 12 yields the mono- and dications 26 and 27, respectively. In contrast to 24, no new band due to an intramolecular transannular charge-transfer interaction is observed in the electronic spectrum of 26, and this is due to an insufficient overlap between the protonated and unprotonated azulene decks in 26. Vilsmeier formylation of 9 with 1.5 mol equivalents of phosphoryl chloride in DMF at room temp. yields 3-formyl-syn-[2.2](1,6)azulenophane (28) in 15% yield. Under the same reaction conditions a double formylation of 9 with 3 mol equivalents of phosphoryl chloride leads to 3,3′-diformyl-syn-[2.2](1,6)azulenophane (29) in 42% yield. The aminomethylation of 9 with paraformaldehyde and N, N, N′, N′-tetramethyldiaminomethane in the presence of acetic acid furnishes the Mannich bases 3-N, N-dimethylaminomethyl-syn-[2.2](1,6)azulenophane (30) and 3,3′-bis(N, N-dimethylaminomethyl)-syn-[2.2](1,6)azulenophane (31) in 40% and 46% yields, respectively.
Type of Medium:
Electronic Resource
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