Synthesis and properties of 5,6-dihydrodipyrrolo[1,2-d;2′,1′-g][1,4]diazepin-11-one
作者:Karen A. Johnston、Hamish McNab
DOI:10.1039/b906802n
日期:——
Treatment of 1,2-di(pyrrol-1-yl)ethane 4 with oxalyl chloride gave a low yield of 5,6-dihydrodipyrrolo[1,2-d;2â²,1â²-g][1,4]diazepin-11-one 2, by an unexpected electrophilic substitutionâdecarbonylation process. The diazepinone 2 is unreactive to electrophiles, but can be deoxygenated to 5,6-dihydro-11H-dipyrrolo[1,2-d;2â²,1â²-g][1,4]diazepine 9 with lithium aluminium hydride. Reaction of 1,1-di(pyrrol-1-yl)methane 5 with triphosgene gives the related dipyrrolo[1,2-c;2â²,1â²-f]pyrimidin-10-one 3. NMR spectroscopic and X-ray crystal structure comparisons of 2 and 3 show that there is unexpectedly greater conjugation in the compound with the core seven-membered ring, 2, even though the molecule as a whole is less planar than 3. The corresponding reactions of 4 or 5 with thiophosgene did not give cyclisation products but the O-methyl thioesters 7 and 8 were obtained (89 and 27%, respectively).
1,2-二(吡咯-1-基)乙烷4与草酰氯反应得到的5,6-二氢-双吡咯[1,2-d;2′,1′-g][1,4]二氮唑-11-酮2的产率较低,这是由于意外的电亲核取代-去羰基反应过程。二氮唑酮2对电亲核试剂无反应性,但可以通过锂铝氢还原为5,6-二氢-11H-双吡咯[1,2-d;2′,1′-g][1,4]二氮唑9。1,1-二(吡咯-1-基)甲烷5与三磷酸酯反应得到相关的双吡咯[1,2-c;2′,1′-f]嘧啶-10-酮3。对比2和3的NMR光谱和X射线晶体结构显示,尽管整体分子3的平面度低于2,但在核心七元环化合物2中意外地具有更大的共轭效应。4或5与硫酰氯的相应反应未产生环化产物,但获得了O-甲基硫酯7和8(分别为89%和27%)。