TOBACCO CHEMISTRY .78. BIOTRANSFORMATIONS OF TOBACCO CEMBRANOIDS USING PLANT-CELL CULTURES OF NICOTIANA-SYLVESTRIS

Earlier bioconversion experiments involving (1S,2E,4S,6R,7E,11E)-2,7,1 1-cem-bratriene-4,6-diol have been extended to include four related co mpounds, i.e., the corresponding 11S,12S-epoxide (1) and 11S,12S-dihyd roxy (2) derivatives as well as the seco-cembranoids hyl-11-isopropylp entadeca-3,7,12-triene-2,14-dione (3) and isopropyl-6,8-dihydroxy-14-o xopentadeca-4,9-dienal (4). These have been incubated with plant cell cultures of Nicotiana sylvestris or cell homogenates thereof. A novel hydroxylation at the tertiary carbon of the isopropyl group is observe d in the case of the epoxide 1, while five- and six-membered epoxides are derived from the tetraol 2. The diketone 3, undergoes epoxidation of the same 7,8-double bond as does the parent diol, while the keto al dehyde 4 undergoes reduction with the formation of a keto triol which is also the obvious intermediate of the second product encountered, a ketohydroxvtetrahydrofuran.