Molecules has pulled a 2010 article by a trio of chemists from Tunisia who tried — and succeeded, for a while, at least — to publish the same data twice. The article was titled “An Expeditious Synthesis of [1,2]Isoxazolidin-5-ones and [1,2]Oxazin-6-ones from Functional Allyl Bromide Derivatives.” And indeed it was expeditious. Here’s the notice:
Excerpt: We have been made aware that the figures, tables, compounds and experimental data reported in the title paper  are duplicated in another publication by the same authors . Comparing the received dates of both articles, it is apparent that, although the Molecules article was published more than a year earlier, it was submitted to MDPI several weeks after the manuscript of  was received by Taylor and Francis. Since it is our policy to only consider for publication original unpublished articles that are not under consideration by another journal, and do not potentially infringe any copyright, and all authors explicitly agree to this as a condition for processing their submissions, we view this as a deliberate attempt to double publish this material and a violation of our rules on this matter. MDPI is a member of the Committee on Publication Ethics and takes the responsibility to enforce strict ethical policies and standards very seriously. To ensure the addition of only high quality scientific works to the field of scholarly publication, paper  is retracted and shall be marked accordingly. We apologize to our readership that this went undetected until now.
The Taylor and Francis paper is a 2011 article in Synthetic Communications, which also has been retracted, as this freely available notice explains:
We, the Editor and Publisher of Synthetic Communications, are retracting the following article:
Aïcha Arfaoui, Imen Beltaïef, and Hassen Amri, “One-Pot Synthesis of [1,2]Isoxazolidin-5-ones and [1,2]Oxazin-6-ones,” Synthetic Communications, 41.10 (2011): 1536–1543, http://dx.doi.org/10.1080/00397911.2010.487292We are now cognizant that a substantially similar version of this article was simultaneously submitted to and published in the journal Molecules:
Aïcha Arfaoui, Imen Beltaïef, and Hassen Amri, “An Expeditious Synthesis of [1,2]Isoxazolidin-5-ones and [1,2]Oxazin-6-ones from Functional Allyl Bromide Derivatives,” Molecules, 15.6 (2010): 4094–4101, http://dx.doi.org/10.3390/molecules15064094
This action constitutes a breach of warranties made by the authors. We note that we received, peer-reviewed, accepted, and published the article in good faith based on these warranties, and censure this action.
The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as RETRACTED.
Update, 6 p.m. Eastern, 11/12/14: Editor Martyn Rittman reached out to us with more information:
We were alerted to this case by a reader, and after consultation with the Editor-in-Chief decided that a retraction was necessary. The rest of the details can be found in the retraction notice. Regarding authors continuing to publish, we make a decision on a case by case basis. If there is an accusation of misconduct we will investigate as far as possible, possibly with the assistance of third parties such as university bodies. If the claim is substantiated we may consider blocking the authors for a period of time, depending on the gravity of the offense.