| CPC C07D 417/12 (2013.01) [A61K 45/06 (2013.01)] | 13 Claims | 
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               1. A method of preparing a compound of formula I: 
              ![]() or a pharmaceutically acceptable salt thereof; 
                wherein said method comprises the step of reacting compound of Formula (I-1): 
              ![]() with a compound of Formula (I-2): 
              ![]() in the presence of a base; 
            wherein 
                R is a H or a nitro group; 
                R1 and R6 are as defined below or groups which may undergo further transformation to provide a compound of Formula (I-1) wherein 
                R1 is selected from hydrogen, amino and hydroxy-substituted C1-2alkyl; 
                R2 is hydrogen; 
                R3 is selected from C1-2alkyl and halo-substituted-C1-2alkyl; 
                R4 is hydrogen; 
                R5 is selected from hydrogen and halo; and 
                R6 is selected from hydrogen and halo. 
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