Amorphane

Amorphanes 38-40 were also isolated from Acanthella cannabina. These are trans-fused and functionalized at C-l rather than C-10 which was the case with the Halichondria metabolites. The carbocyclic skeleton was demonstrated when 39 was dehydrogenated to yield cadalene (37). Relative stereochemistry assignments were secured by extensive 13C- and XH NMR experiments [39], in which 13C data were particularly useful, as illustrated in the case of isothiocyanate 41, one of several isothiocyanates obtained from Acanthella pulcherrima [20]. The ds-fused ring was corroborated by comparing the corresponding chemical shifts with those of enf-epicubenol (42) [20], which has the same relative stereochemistry. 

Isothiocyanatocubebane (128) and 10-isothiocyanatoguaia-6-ene (129) were isolated from a Palau sponge, Axinyssa aplysinoides, which is rich in isocyano-related sesquiterpenoids [44, 49]. The former (128) is apparently related to the amorphanes (Sect. 4.1.3) and the latter (129) to the aromaden-dranes [Sect. 4.1.5]. 

These compounds range through monocyclic (with a bisabolane framework), bicyclic (with an eudesmane, amorphane, axane, guaiane, isodaucane, or gorgonane framework), tricyclic (with an aromadendrane, cubenane, maaliane, pupukeanane, or trachyopsane framework), and spiro[4,5]decane carbon skeletons. 

Recent synthetic studies (Scheme 34) have shown that the seco-amorphane structure (332) previously assigned to humbertiol is incorrect.139... 

Agrawal, P. K. Bishnoi, V. Studies on Indian medical plants. 42. Sterol and taraxastane derivatives from Artemisia annua and a rational approach based upon C-13 NMR for the identification of skeletal type of amorphane sesquiterpenoids. Indian J. Chem., 1996, 35B 86-88. 

Ammonia buffer (pH9.5), 1169 Ammonia solution, dilute, 1169 Ammonia solution, strong, 1169 Ammoniacal Silver Nitrate (test), 129 Ammonium mandelate, 718 Ammonium polysulphide solution, 1169 Ammonium sulphide solution, 1169 Amobarbital, 353 Amobarbital sodium, 353 Amodiachin, 347 Amodiaquine, 347 Amodiaquine hydrochloride, 347 Amolanone, xvii Amopyroquine, xvii Amorphan Depot, 437 Amosyt, 549... 

Although comparatively rare, sesquiterpenoids containing isocyanide, isothiocyanate, and formamide, groups have been isolated from species of marine sponge (cf. Vol. 5, p. 74 Vol. 6, pp. 65, 87, 89). Included in this small group are the previously reported amorphane derivatives (164a—c), and a complete account of... 

Cadinane, Amorphane, Muurolane, Bulgarane, and related Tricyclic Sesquiterpenoids... 

A new amorphane sesquiterpene y-lactol derivative, O-methylbaccharocephol, Fig. (18) was isolated from Baccharis sphaerocephala B N [49], This compound possesses a very rare type of carbon skeleton, with two ci.v-fused six-membered rings, a five-membered-ring y-lactone and an epoxide. Chemical analysis of Baccharis salicina Torr Gray afforded two new guaianolides, bacchariolides A, Fig. (19) and B, Fig. (20) [50],... 

---