Mindlusion said:
what would have a peak at 400m/z?
Is that the 399.0 peak? Would this be as M+H?
If so, a molecular formula of C
21H
22N
2O
6 checks out (M+H=399.42), plugging that into PubChem gives nothing. This is, of course, shooting in the dark and without NMR it'll be bloody difficult. Trial and error variations (by hand, at least) will take ages. I've had a brief look for an online MW to formula converter - there must be one somewhere - but to no avail, they all convert formulas to MW but not the other way round. And a molecular formula can correspond to thousands of compounds so that's not much help.
That given, here's the results of my brainstorming:
That MW is in the range of a tripeptide: C
23H
17N
3O
4 = 399.40. That's rather short on hydrogens, though.
Or a dimeric isoquinoline, maybe with an oxygen bridge (as in pilocereine): C
22H
26N
2O
5 = 398.45
This would be plausible, and I've attached a couple of structural formulas that would be both possible and likely. Maybe this helps - I certainly hope so!
EDIT: the lower of the two rings in each structure has a 5,6,7-oxygen substitution pattern which is unknown among the cacti, it was drawn this way because it was easier than drawing the more usual 6,7,8-substitution pattern! (And of course, the
methylenedioxy-substituted cactus isoquinoline alkaloids have this moiety at the 7,8-position.)