SYNTHESIS AND PROPERTIES OF SYN-[2.2](1,6)AZULENOPHANES AND SYN-[2.2](4,6)AZULENOPHANES AND MACROCYCLIC AZULENOPHANES

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 iodin e under high-dilution conditions in 17% yield, along with the macrocyc lic [2.2.2.2](1,6)azulenophane (10) (3%), and [2.2.2.2.2.2] (1,6)azule nophane (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 fu rnishes the mono- and dications 24 and 25, respectively, of which the first exhibits a charge-transfer band in its electronic spectrum, indi cating a transannular interaction between the protonated and unprotona ted azulene units. Protonation of 12 yields the mono- and dications 26 and 27, respectively. In contrast to 24, no new band due to an intram olecular transannular charge-transfer interaction is observed in the e lectronic spectrum of 26, and this is due to an insufficient overlap b etween the protonated and unprotonated azulene decks in 26. Vilsmeier formylation of 9 with 1.5 mol equivalents of phosphoryl chloride in DM F 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 w ith 3 mol equivalents of phosphoryl chloride leads to 3,3'-diformyl-sy n-[2.2](1,6)azulenophane (29) in 42% yield. The aminomethylation of 9 with paraformaldehyde and N,N,N',N'-tetramethyldiaminomethane in the p resence of acetic acid furnishes the Mannich bases N,N-dimethylaminome thyl-syn-[2.2](1,6)azulenophane (30) and ,N-dimethylaminomethyl)-syn-[ 2.2](1,6)azulenophane (31) in 40 % and 46 % yields, respectively.