Chemistry of acronycine, XII. Further oligomers of noracronycine.

The polymerization of noracronycine (2) with methanolic HCl has yielded a second tetramer of 2, designated as AB-4 and determined to have the structure 7 through spectroscopic analysis. Two further pentamers of 2, designated as AB-6A and AB-6B, have also been obtained, and their structures are tentatively proposed as 9 and 5, respectively.