Tilivalline 1, a metabolite from Klebsiella pneumoniae var. ocytoca, was easily synthesized in five steps from (S)-proline and 3-(benzyloxy) isatoic anhydride 4 g. This synthesis is based on modified Curtius reactions of 3-substituted phthalic anhydrides 11 to 3-substituted isatoic anhydrides 4, conversion of lactams 6 to the acyliminium precursors 7 and stereoselective introduction of indole from the less hindered side of 7.
![5-甲氧基-1H-苯并[d][1,3]恶嗪-2,4-二酮结构式](https://image.chemsrc.com/caspic/177/67765-42-8.png)
![(+)-(11S,11aS)-1,2,3,10,11,11a-hexahydro-9-(benzyloxy)-10-carbobenzyloxy-11-(3'-indolyl)-5H-pyrrolo[2,1-c][1,4]benzodiazepin-5-one结构式](https://image.chemsrc.com/caspic/386/125299-55-0.png)
![(11aS)-1,2,3,10,11,11a-hexahydro-9-(benzyloxy)-10-(benzyloxycarbonyl)-5H-pyrrolo[2,1-c][1,4]benzodiazepin-5,11-dione结构式](https://image.chemsrc.com/caspic/348/125299-56-1.png)
