Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2017 May 24;12(5):e0178012. doi: 10.1371/journal.pone.0178012

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© 2017 Xu et al

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

PMC Copyright notice

Fig 6 — Usnic acid was detected in one chemotype of Icelandic Montanelia disjuncta taxon. Structure a, b, d, e and f are characteristic fragment ions in MS² spectrum (S3 Fig). Structure b is a resonance contributor of structure a but not a true structure of usnic acid. Structure c is only reported in LDI or FAB-MS. (Abbreviation: RDA: retro-Diels—Alder reaction; LDI/FAB: laser desorption ionization/fast atom bombardment).