Aragupetrosine alkaloids

The perhydropyrido[2,l-Z)][l,3]oxazine skeleton is a constituent part of macrocyclic xestospongine/araguspongine and aragupetrosine alkaloids... 

The perhydropyrido[2,l-b][l,3]oxazine skeleton is a constituent part of macrocyclic xestospongine/araguspongine and aragupetrosine alkaloids isolated from different marine sponges. Pyrido[2,l-fo][l,3]oxazines, pyrido[2,l-fc][l,3]thiazines, and [l,3]oxazino[3,4-a]quinolines are also applied as key intermediates in the total syntheses of different alkaloids. Other examples of these ring systems have aroused much interest owing to their valuable pharmacological properties. 

Macrocyclic quinolizidine or 1-oxaquinolizidine alkaloids, aragu-spongines B-H (236-242) and J (243) (206) and aragupetrosine A (244) (207) were isolated from an Okinawan sponge (Xestospongia sp.) together with the previously known petrosin (245) (208) and petrosin A (246) (209). These alkaloids show vasodilating activity. 

Aragupetrosine A, A new Vasodilative Macrocyclic Quinolizidine Alkaloid from an Okinawan Marine Sponge Xestospongia sp. Kobayashi, M. Kawazoe, K. and Kitagawa, I. Tetrahedron Lett. 1989, 30, 4149. 

Kobayashi, M., Kawazoe, K., and Kitagawa, 1. (1989c) Aragupetrosine A, a new vasodilative macrocychc quinolizidine alkaloid from an Okinawan marine sponge Xestospon a sp. Tetrahedron Lett., 30, 4149-4152. 

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