Stemospironine, a New Insecticidal Alkaloid ofStemona japonicaMiq. Isolation, Structural Determination and Activity

Sessilifoliamine A and sessilifoliamide J: new alkaloids from Stemona sessilifolia

“…have been used in China and Japan as an insecticide and also as a remedy for cough, and their biological activities are considered to be related to their alkaloid components. [4][5][6] In our studies on the chemical constituents of S. sessilifolia, 7 we isolated two new alkaloids, sessilifoliamine A (1) and sessilifoliamide J (2), with novel alkaloid skeletons (Fig. 1).…”

Stemocurtisine, the First Pyrido[1,2-a]azapine Stemona Alkaloid

“…The absolute configuration of 2 is not known but is assumed based on the known configurations of Stemona alkaloids with similar C,D-ring structures. 6,[9][10][11][12][13][14][15][16][17] The X-ray structure of 2 also showed that the piperidine A-ring adopts a chair-like conformation and is connected to the B-and C-rings through an ether bridge between C-1 and the quaternary acetal carbon C-9 readily identified in the 13 C NMR spectrum.…”

“…2 A few of these alkaloids do not fit these five structural groups and have a more complex bridged structure or ring structures that most likely arises from initial oxidative cleavage of the pyrrolo [1,2-a] presence of the C-and D-ring system that is typically found in the stemoamide group of alkaloids, including stemofoline (1). 1,6,[9][10][11][12][13][14][15][16][17] The 13 C/DEPT NMR spectra of 2 indicated four methine carbons, and six methylene carbons and, unlike the other Stemona alkaloids, except 1 and its didehydro and 2'-hydroxy derivatives, 2 a quaternary carbon at  120.4 was apparent, indicative of a acetal-like structure (C-9).…”

Construction of spirolactones with concomitant formation of the fused quaternary centre – application to the synthesis of natural products

“…79 Stemospironine is another Stemona alkaloid that exhibits antiinsecticidal properties, and was isolated from Stemona japonica by Murakoshi and coworkers. 80…”