Structure elucidation of 11‐amino‐8‐hydroxypentacyclo[5.4.0.0 2, 6 .0 3, 10 .0 5, 9 ]undecane‐8,11‐lactam through selective acetylation and complete 1 H and 13 C NMR spectral assignment of the mono‐, di‐ and triacetates

NMR techniques cannot unambiguously distinguish between 11‐amino‐8‐hydroxypentacyclo[5.4.0.0 2, 6 .0 3, 10 .0 5, 9 ]undecane‐8,11‐lactam and 8‐amino‐11‐hydroxypentacyclo[5.4.0.0 2, 6 .0 3, 10 .0 5, 9 ]undecane‐8,11‐lactam, both of which are possible products during the reaction of pentacyclo[5.4.0.0 2, 6 .0 3, 10 .0 5, 9 ]undecane‐8,11‐dione with Strecker reagents. Treatment of 11‐amino‐8‐hydroxy‐pentacyclo[5.4.0.0 2, 6 .0 3, 10 .0 5, 9 ]undecane‐8,11‐lactam with acetic anhydride at room temperature produced a monoacetate. With acetic anhydride containing sodium acetate, a triacetate was obtained at reflux temperature. Treatment with acetyl chloride and N , N ‐dimethylaniline produced a diacetate. High‐field 1 H and 13 C NMR techniques were used in the structure elucidation and assignment of the different NMR resonances of these three acetylated compounds. Copyright © 2004 John Wiley & Sons, Ltd.