反应详情

The synthetic strategy used in the preparation of compounds 4, 5, 6, 7, and 8 is illustrated in FIG. 2. Polychlorinated pyridines were synthesized from the 2-amino-4-chloro-pyridine (compound 3). For example, compound 3 was dissolved in concentrated hydrochloric acid (HCl), reacted at 0° C. with hydrogen peroxide (H2O2), and allowed to warm to room temperature yielding a mixture of 2-amnino-4,5-dichloro-pyridine (compound 4), 2-amino-3,4-dichloro-pyridine (compound 5), and 2-amino-3,4,5-trichloro-pyridine (compound 6). In another method, compound 3 was dissolved in concentrated hydrochloric acid (HCl) and heated at reflux temperature to yield 2-amino-4,5-dichloro-pyridine (compound 4) in 97% yield. In another method, compound 3 was dissolved in concentrated hydrochloric acid (HCl), reacted at 0° C. with hydrogen peroxide (H2O2), and allowed to warm to room temperature yielding 2-amino-3,4,5-dichloro-pyridine (compound 6) in 80% yield. In still another method, compound 3 was reacted with trimethylacetyl chloride ((CH3)3COCl) to yield 2-trimethylacetamido-4-chloro-pyridine (compound 7). Compound 7 was then reacted with N-chlorosuccinimide (NCS) to yield 2-trimethylacetamido-4,5-chloro-pyridine (compound 8). Compound 8 was then reacted with hydrochloric acid (HCl) to yield 2-amino-4,5-chloro-pyridine (compound 4).