ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
It is shown here that the stoloniferan coral Sarcodictyon roseum of east Pyrenean waters contains four novel diterpenoids, sarcodictyin C ((-)-3), D ((-)-4), E ((+)-5), F ((+)-6), which are related to sarcodictyin A ( = (-)-(4R,4aR,7R,10S,11S,12aR,1Z,5E,8Z-7,10-epoxy-3,4,4a,7,10,11,12,12a-octahydro-7-hydroxy-6-(methyoxycarbonyl)-1,10-dimethyl-4-(1-methylethyl)-benzocyclodecen-11-yl (E)-N1-methylyrocanate; ((-)-1), previously isolated from the same coral. Sarcodictyin C ((-)-3) and D ((-)-4) and the 3α-hydroxy and 3α-acetoxy derivatives of (-)-1), sarcodictyin E ((+)-5) is the (Z)-urocanate isomer of (-)-3), and sarcodictyin F ((+)-6) is the 1α-hydroxy-2-ene isomer of (-)-3. In all cases, the nine-membered ring is locked, and the molecule stabilized, by the urocanic appendage; when this is removed in MeOH/KOH, the C(11)-O- function is free to attack at C(5), and retro-condensations then lead to the ring-contracted butenolides 11 (from (-)-3) or 10 (from(-)-1) with extrusion of the hydroxyfuran nucleus (Scheme 3). Under the same conditions, with (-)-3, the C(3)-O- group competitively attacks at C(5), the hydroxyfuran nucleus is expelled, and aldehyde 14 is formed. Peculiarly, in the reaction of (-)-3 with MeOD/KOD, the ring-contracted butenolide 17 contains D at the 4′-ax position. The sarcodictyins are unique in these chemical properties, not shared by the cladiellanes which have the same C-skeleton.
Additional Material:
4 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19880710504
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