1. The Ullmann Synthesis of Biaryls.
2. The nitro group activates a halogen atom toward the Ullmann reaction (reference 2).
3. G. P. Sharnin, B. I. Buzykin and R. Kh. Fassakhov, U.S.S.R. Patent 233,671; December 24, 1968,
4. prepare VIa by subjecting VIII to cyclization in the presence of phosphorus oxychloride at the b.p. of the reaction mixture [Chem. Abstr., 70, 115162s (1969)]. Our attempts to prepare VIa from VIII employing re-fluxing phosphorus oxychloride or phosphorus oxychloride in high boiling solvents gave only trace amounts of VIa (by tlc analysis) even after prolonged reaction times. The Russian authors describe a preparation of VIII by treating 2,4,6-trinitrobenzoyl hydrazide with 2,4,6-trinitrobenzoyl chloride in dixoane at 50-60°