A solution of 5 gm of the compound from Step C, 50 mL of 2-methyl THF 5 mL, triethanolamine and 2.5 mL of trimethyl silyl azide was heated at 50° C. until reaction completion. When the reaction was judged complete, the reaction mixture was cooled and 50 mL of 1 N sodium hydroxide added. The layers were separated and the organic layer washed with 50 mL of 10% citric acid. The organic layer was concentrated and triturated with hexane to yield 4.6 of the desired compound. 85% yield. 1H NMR (400 MHz, CDCl3) 7.84 (s, 2H), 7.74 (m, 3H), 4.90 (s, 4H)C, H, N, Calculated, (found) 42.92 (42.98), 2.20 (1.97), 13.90 (13.54)
