Abstract:

One of the main problems in performing on-line evaluations in Chemistry, is the handling of chemical structures. The different representations of the chemical structures, make it very difficult for the implementation of an automatic electronic comparison for evaluations.
One way of circumvent this problem is using linear notations for chemical structures. One of the simplest and more widely used notations, is the SMILES notation, in which by following very simple rules, a graphical representation of a chemical structure can be transformed into a linear sequence.
Aromatic compounds are represented by Small Letters, and aliphatic compounds by Capital Letters. In this way, it can be used in a text comparison for checking the accuracy of the answer.
For instance, Benzene in the SMILES notation considers the aromatic compound as a sequence of small letters and is represented as; c1ccccc1, the number after the first and last letter implies the formation of a ring.
In the case of Toluene, having an aromatic ring with six carbons and an aliphatic carbon, the notation will be c1ccccc1C.
When a branching is found it is included in brackets, for instance, 2-Methylbutane is represented as; CC(C)CC
If a double bond is present as in acetone, the notation is CC(=O)C.
Stereochemistry is also considered.
This type of notation can be implemented very easily for electronic test.
In our case, we are using the Moodle platform for teaching our chemical courses (http://organica1a.org), and the use of the SMILES notation allows us to be able to perform evaluations in a very simple way.
This sequence also can be transformed into a 3D structure and be analyzed by Molecular Modeling programs in a 3D environment, to teach students of the different parameters involved in the structures. These tools allow the study of complex structures in a very simple way.

The work was partially supported by a grant from Dirección General de Asuntos del Personal Académico (DGAPA) Universidad Nacional Autónoma de Mexico (UNAM) IX200810.

Keywords:

Chemical Evaluations, SMILES, Moodle, Organic Chemistry, 3D Chemistry.