Narcissus and Daffodil

180 J. Bastida and F. Viladomat
It is worth noting that the montanine type alkaloids are distinguished from the
other ring type systems by the downfield signal at around 150 ppm, assignable to
the quaternary olefinic C-11a.
Mass Spectrometry
Extensive studies on the Mass Spectrometry of Amaryllidaceae alkaloids by electron
impact were reported in the 1960s and 1970s (Fales et al., 1969, 1970; Ibuka et al.,
1966; Onyiriuka and Jackson, 1978; Samuel, 1975). The fragmentation patterns
in the Electronic Impact Mass Spectrometry (EIMS) of various skeletal types are
fairly well documented and have considerable diagnostic value.
Lycorine type
The molecular ion appears as a quite intense peak, and generally suffers the loss of
water, as well as C-1 and C-2 and their substituents by a retro Diels-Alder fragmentation
(Figure 6.13). The loss of water is not present in the spectra of acetyl
derivatives.
The ease of the loss of water from the molecular ion was found to be greatly
dependent on the stereochemistry of the C-2 hydroxyl group. Thus, in the mass
spectrum of lycorine (1), the relative intensity is low, while in 2-epilycorine it is the
base peak (Kinstle et al., 1966).
Homolycorine type
In this structure type, the cleavage of the labile bonds in ring C by a retro
Diels-Alder reaction is dominant, generating two fragments: one, the more characteristic,
represents the pyrrolidine ring (plus substituents in position 2), and the
other (a less abundant fragment) encompasses the aromatic lactone or hemilactone
moiety (Figure 6.14).
Figure 6.13 Mass fragmentation pattern of lycorine (1).