Erratum to: Chem Central J (2017) 11:81 DOI 10.1186/s13065-017-0305-1
After the publication of this work  it was noticed that in the legend for scheme 5: ‘(left 11, right 12)’ was accidentally included and should be removed. The drawing for scheme 6 is incorrect and needs to be replaced with the correct version.
We apologise for these errors.
The original article was corrected.