def get_reaction_list(df):
    """
    get the list of reaction from a dataframe that contains reaction column
    input:dataframe with reaction column (df)
    output: list of reaction (list)
    """
    reaction_list = []
    for index,row in df.iterrows():
        for reaction in row['reaction']:
            reaction_split = reaction.split("[RN:")[-1]
            if reaction_split.startswith("R") and not reaction_split.startswith("RN"):
                for i in reaction_split[:-1].split(" "):
                    reaction_list.append(i)
    return reaction_list