**2.1 Simple phenolic compounds**

Phenolic compounds that contain one phenol unit (or a derivative of it) are considered "simple". Fundamentally, they are substituted phenol compounds. Simple phenolic compounds have C6 general skeleton representation. The general structure is shown below (**Figure 2**). The group denoted by "R" (an organic group which could be alkyl, alkenyl, aryl …etc. or hydroxy, alkoxy, amino …etc) which can be in the *ortho* (*o*), *meta* (*m*), or *para* (*p*) positions of the aromatic ring. These descriptors refer, with respect to the position of the hydroxyl group constituting phenol which is given position 1, to 1,2-, 1,3, and 1,4-carbon relationship respectively.

Below are some simple phenolic compounds.
