Four 1-(3,4-methylenedioxyphenyl)-alkanes having linear ten, eleven, twelve and fourteen carbon atom chains, found in the roots ofPiper darienenceD.C., were separated by HPLC and their structures determined by mass spectrometry and NMR spectroscopy. Conventional 1D NMR methods were used for1H chemical shifts assignment of the main compound dihydropipataline (3) [1-(3,4-methylenedioxyphenyl)‒dodecane]. The13C NMR assignment was carried out using conventional considerations and 2D NMR techniques (HETCOR and FLOCK) in combination with spectral13C NMR simulation andab initioDFT-GIAO NMR calculations.
1H and13C NMR assignments of dihydropipataline, the main of four long-chain 1-(3,4-methylenedioxyphenyl)-alkanes fromPiper darienenceD.C.