0 Reagents:(a) HCOZMe, NaOMe, Eh0;(b) HOAc, KOAc, 4-pyridylNHNH2;(c) NJV- dimethylalloxan, A, xylenes. the basis of lH NMR and NOE experiments. Irradiation of (2-10 methyl group resulted in 10-15% enhancement of C-11 proton16 signal intensity for both the compounds. However, no enhancement of C-8 proton signal was observed for 12a. In contrast 12b showed an 11% enhancement of C-8 proton thus providing the ...