A chemical study of burley tobacco flavour (Nicotiana tabacum L.) VI. Identification and synthesis of four irregular terpenoids related to solanone, including a 'prenylsolanone'.

Four novel constituents of Burley tobacco condensate have been identified as (E)-5-isopropyl-7-(2-methyl-tetrahydrofur-2-yl)-hept-6-en-2-one ( G ), (E)-5-isopropyl-7-(2-methyl-tetrahydrofur-2-yl)-hept-6-en-2-ol ( H ), (E)-4-methyl-7-isopropyl-10-oxo-undec-5-en-4-olide ( I ), and (E, E)-6,12-dimethyl-9-isopropyltrideca-5,10,12-trien-2-one ( J ) or ‘prenylsolanone’. Compounds G , H , and I were synthesized from norsolanadione ( 1 ), compound J from solanone ( A ). These substances belong to a growing family of tobacco metabolites structurally related to solanone ( A ). Their possible formation from cembrene-type precursors is briefly outlined.