Reactions of Pyridine Analogues of Aza-ortho-xylylenes Generated from 1,3-Dialkylpyridosultams
作者:Szymon Kosinski、Krzysztof Wojciechowski
DOI:10.1002/1099-0690(200004)2000:7<1263::aid-ejoc1263>3.0.co;2-e
日期:2000.4
2,3-Dihydro-3-imino-2-methylenepyridines generated by thermal extrusion of SO2 from 1,3-dialkyl-1,3-dihydroisothiazolo[4,3-b]pyridine 2,2-dioxides (1,3-dialkylpyridosultams), underwent [1,5] hydrogen shifts, which led to 3-alkylamino-2-vinylpyridine derivatives. Cycloalkanespiro-3-pyridosultams 12, which were easily obtained by alkylation of pyridosultams with alpha,omega-dihaloalkanes, gave, in a similar reaction, 3-alkylamino-2-cycloalkenylpyridine derivatives 14 in good yields. Cyclobutanespiro-3-pyridosultam 12b, after thermal extrusion of SO2, formed cyclobutenyl derivative 14b, which underwent a ring-opening reaction to form butadiene derivative 15. The latter can be trapped with dienophiles, for example, N-phenylmaleimide.