1H and 13C assignments of five cembrenes from guggul

Chemical shift assignments of (1)H and (13)C of five cembrene compounds isolated from the hexane extract of guggul, the resin of Commiphora mukul, are reported. Using (1)H, (13)C, and 2D NMR methods their structures were determined as cembrene (1-isopropyl-4,8,12-trimethyl-cyclotetradeca-2,4,7,11-tetraene), cembrene A (1-isopropenyl-4,8,12-trimethyl-cyclotetradeca-4,8,12-triene), cembrenol (1-isopropyl-4,8,12-trimethyl-cyclotetradeca-3,7,11-trienol), mukulol (1-isopropyl-4,8,12-trimethyl- cyclotetradeca-3,7,11-trienol), and verticillol (4,8,12,15,15-pentamethyl-bicyclo9.3.1]pentadeca-3,7-dien-12-ol).