Epimeric Isopavine N ‐Oxides from Roemeria refracta

Roemeria refracta DC. (Papaveraceae) of Turkish origin yielded two novel epimeric N ‐oxides, (−)‐(5 R , 11 S ,14 R )‐reframidine N ‐oxide ( = (−)‐(5 R , 11 S ,14 R )‐11,12‐dihydro‐14‐methyl‐11,5‐(iminomethano)‐5 H ‐cyclohepta[1, 2‐ f : 4, 5‐ f ′]bis[1,3]benzodioxole 14‐oxide; 1 ) and (−)‐(5 R , 11 S , 14 S )‐reframidine N ‐oxide ( = (−)‐(5 R , 11 S , 14 S )‐11, 12‐dihydro‐14‐methyl‐11, 5‐(iminomethano)‐5 H ‐cyclohepta[1, 2‐ f :4, 5‐ f ′]bis[1, 3]benzodioxole 14‐oxide; 2 ). The isolated (−)‐roelactamine ( = (−)‐11, 12‐dihydro‐14‐methyl‐11, 5‐(iminomethano)‐5 H ‐cyclohepta[1, 2‐ f :4, 5‐ f ′]bis[1, 3]benzodioxol‐15‐one, 4 ) is the first natural isopavinoid incorporating a lactam group. The epimeric (−)‐15‐(2‐oxopropyl)reframidines ( = (−)‐1‐[11, 12‐dihydro‐14‐methyl‐11, 5‐(iminomethano)‐5 H ‐cyclohepta[1, 2‐ f :4, 5‐ f ′]bis[1, 3]benzodioxol‐15‐y1]propan‐2‐ones; 5/6 ) and the epimeric (−)‐ethyl (reframidin‐15‐yl)acetates ( = (−)‐ethyl [11, 12‐dihydro‐14‐methyl‐11, 5‐(iminomethano)‐5 H ‐cyclohepta[1, 2‐ f :4, 5‐ f ′]bis[1, 3]benzodioxol‐15‐y1]acetates; 7/8 ) are probably artifacts. (±)‐Coclaurine ( 9 ), (±)‐ N ‐methylcoclaurine ( 10 ), (−)‐roemeridine ( 11 ), and N ‐feruloyltyramine ( 12 ) are also isolated from R. refracta together with the previously reported bases. Specific 13 C‐NMR assignments are reported for the first time for the isopavines.