... 7 2223 7 R3 i r 4, Me }I M e 4 8 9 3 Chart 2 r —"' i z pig H0 H0 P 10 m/z 191 m/z 146 IN —> N <— N/H H 6c 11 12 R3 R3 N -—"~ N H AC Ac 7 13 14 Chart 3 and 7c in the ratio of 72:25. ... 2224 Vol. 31 (1983) from the characteristic trans vinyl methyl signals in the NMR spectrum. ...