Studies on diazepines. XV. Photolysis of thieno-, furo-, and pyrrolo-(b)pyridine N-imides: Formation of fused 1H-1,2- and 3H-1,3-diazepines.
作者:TAKASHI TSUCHIYA、MICHIKO ENKAKU、SATORU OKAJIMA
DOI:10.1248/cpb.29.3173
日期:——
Irradiation of the 2-methylpyridine N-acylimides (12b-d and 17a-c) condensed with a thiophene, furan, or pyrrole ring on the b-side of the pyridine ring gave the corresponding fused 1H-1, 2-(13b-d and 18a-c) and 3H-1, 3-diazepines (14b-d and 19a-c), together with the parent fused pyridines (10 and 15a-c), whereas the N-unsubstituted N-imide (12a) gave only the 1H-1, 2-diazepine (13a) and no 1, 3-diazepine. In this ring-expansion reaction, the initial photo-induced rearrengement may take place on either side of the pyridine nitrogen to give two kinds of diaziridine intermediates (21) and (22) ; the former may give 1, 2-diazepines directly, whereas the latter may further rearrange to the aziridine intermediate (23), followed by ring-expansion to give the 1, 3-diazepines. Some reactions of the new diazepines thus obtained were also examined.
Photolysis of thieno-, furo-, and pyrrolo-[b]pyridine N-imides: formation of 3H-1,3-diazepines
作者:Takashi Tsuchiya、Michiko Enkaku、Satoru Okajima
DOI:10.1039/c39800000454
日期:——
Photolysis of pyridine N-ethoxycarbonylimides condensed with thiophen, furan, and pyrrole rings on the b-side of the pyridine ring affords the corresponding novel 1H-1,2- and 3H-1,3-diazepines, respectively.