MAEΔΔδ

The computation of the MAEΔΔδ parameter is useful for facilitating the configuration assignment of groups of stereoisomers by the combination and comparison of experimental and predicted data sets.

In order to facilitate the MAEΔΔδ parameter, we have released a script (diastereoisomers_assignment_MAE_DDd_v0.sh) working on Linux systems and written in bash. The script can be downloaded at the following link.

For more information about the MAEΔΔδ –based approach for the configuration assignment of groups of stereoisomers, please refer and/or cite to the following publication:

Gianluigi Lauro, Pronay Das, Raffaele Riccio, D. Srinivasa Reddy, and Giuseppe Bifulco. DFT/NMR approach for the configuration assignment of groups of stereoisomers by the combination and comparison of experimental and predicted sets of data. J. Org. Chem. (submitted)

Instructions

calc_data.txt: this file contains the table with the computed chemical shift data correctly aligned atom-by-atom. Each set must be separated from the other by spaces or tabs. Also, the name of each set (e.g. calc_1a, calc_2a, calc_3a, calc_4a) must be specified in the first line of the file, and each name must not contain spaces (that can be replaced by “_” character; e.g. “calc_1a” and not “calc 1a”). Following is an example of the calc_data.txt:

exp_data.txt: this file contains the table with the experimental chemical shift data correctly aligned atom-by-atom, and following the same order as specified in the calc_data.txt file. Each set must be separated from the other by spaces or tabs. Also, the name of each set (e.g. exp_1, exp_2, exp_3, exp_4) must be specified in the first line of the file, and each name must not contain spaces (that can be replaced by “_” character; e.g. “exp_1” and not “exp 1”). Following is an example of the exp_data.txt:

Once available these files, the script can be executed with the following command:

bash diastereoisomers_assignment_MAE_DDd_v0.sh

Then, the results.txt file will be obtained, showing the ranking of the MAEΔΔδ values from the lowest (most promising) to the highest (less promising) and finally pointing out the best comparison alignment scheme between all the possible combinations of experimental sets of data and the computed fixed one. For example, considering the above reported calculated and experimental sets of data, the results.txt output file obtained is the following one:

This result then indicated that the best comparison alignment between the calculated and experimental sets of data is:

calc1 -> exp1

calc2 -> exp2

calc3 -> exp3

calc4 -> exp4