Three years after an unlikely structure first set off chemists’ alarm bells, a study describing a natural product with antibacterial properties has been retractedamid concerns over doctored images.
The paper, published in 2013 in the peer-reviewed open access journal PLoS One, was first picked up by chemistry blogger See Arr Oh in 2015. He was taken aback by the strange chemical structure Xinqing Zhao from Dalian University of Technology, China, and his team had proposed for the marine bacterial alkaloid xinghaiamine A. Among other unusual features, See Arr Oh spotted ‘a previously-unknown-to-science 4-4-5-6 ring system’. After trying – and failing – to assemble a molecular model, he wondered: ‘Can that really be correct?’
Commenters on Derek Lowe’s blog post about the unlikely structure then started digging deeper. Examining the NMR spectra, readers pointed out several problems that seemed to affect the 2D spectra in particular: some cross peaks showed up in different colours, others were surrounded by noise or had clipped edges. ‘No one competent could believe the paper’s structural assignment or vouch for the credibility of its authors,’ Lowe wrote.
Source : paparesearch.com