Noticeably, the Nuclear Overhauser Effect (NOE) correlation of H-7(a-oriented)/H-19 (b-oriented) was observed in the ROESY spectrum. Analysis of the molecular model of compound 1 by the Molecular Structure Model B indicated the a-oriented H-7 and b-oriented Me-19 was spacially adjacent,14 which allowed the ROESY correlation between H-7 and Me-19. The ROESY cross peak H-7/H-19 could be employed as a positive evidence for the presence of b-oriented oxygen bridge between C-7 and C-10 in the future structural determination of rearranged 9 (10/20)- abeoabietane diterpenoids.