Chlorination of 2,5-DMA to obtain DOC is described in PiHKAL (#64). Use is being made of liquid chlorine. In order to avoid this one also could use a second pathway as mentioned by doc himself. I've been thinking how to do this and my suggestion is to start with the incorporation of a nitro-group on the 4-position and then convert it to an N=N, prior to the chlorination. Do you bees have any clue what the expected yields might be and will this reaction give one major product and no isomers? Is the acetylation of the 2,5-DMA, as suggested, necessary?