Occurrence and significance of decahydroquinolines from dendrobatid poison frogs and a myrmicine ant: use of 1H and 13C NMR in their conformational analysis

TF Spande; P Jain; HM Garraffo; LK Pannell; HJC Yeh; JW Daly; S Fukumoto; K Imamura; T Tokuyama; JA Torres; RR Snelling; TH Jones

doi:10.1021/np980298v

Occurrence and significance of decahydroquinolines from dendrobatid poison frogs and a myrmicine ant: use of 1H and 13C NMR in their conformational analysis

J Nat Prod. 1999 Jan;62(1):5-21. doi: 10.1021/np980298v.

Authors

TF Spande¹, P Jain, HM Garraffo, LK Pannell, HJC Yeh, JW Daly, S Fukumoto, K Imamura, T Tokuyama, JA Torres, RR Snelling, TH Jones

Affiliation

¹ Department of Chemistry, Virginia Military Institute, Lexington, Virginia 24450-0304, USA.

PMID: 9917275
DOI: 10.1021/np980298v

Abstract

Structures for 2,5-disubstituted decahydroquinolines (DHQs) are reported for the two diastereomeric pairs cis-275B (14) and cis-275B' (15) and 5-epi-trans-269AB (18) and trans-269AB (19), all isolated from skin extracts of dendrobatid frogs, and for 5-epi-cis-275B' (16) and 5-epi-trans-275B (17) found in the extracts of virgin queens of a myrmicine ant [Solenopsis (Diplorhoptrum) azteca]. Detection of such DHQs in an ant, their first reported occurrence, strengthens a dietary hypothesis for the origin of the approximately 30 DHQs that have been detected in extracts of frog skin. NMR data on the two conformers of cis-decahydroquinoline permit assignment of ring conformations and stereochemistry to cis-DHQs of the "N-endo" type or the "N-exo" type. These conformations are also assigned on whether H-8a is equatorial or axial as determined with E-COSY or 1D-HOHAHA spectra.