Mass spectra of the diterpenoid hydrocarbons in A. compacta resins. The KI values relative to n-alkanes on a DB-5 column are shown in parentheses on each mass spectrum: (a) 20-normulina-11,13-diene (III), (b) 20-norazorell-13-ene (IV), (c) 13β(H)-20-normulinane (VI), (d) 13α(H)-20-normulinane (VI), (e) 13β(H)-20-norazorellane (V), (f) 13α(H)-20-norazorellane (V), (g) azorell-13-ene (VIII), (h) 13β(H)-azorell-14-ene (VII), (i) 13α(H)-azorell-14-ene (IX), (j) mulina-11,13-diene (XI), (k) 13β(H)-mulina-11,14-diene (X), (l) 13α(H)-mulina-11,14-diene (XII), (m) 13β(H)-azorellane (XIII), (n) 13α(H)-azorellane (XIV), (o) 13β(H)-mulinane (XV), and (p) 13α(H)-mulinane (XVI).