Stemodane and stemarane diterpenoid hydroxylation by Mucor plumbeus and Whetzelinia sclerotiorum.

Incubation of stemodin (1) with Mucor plumbeus ATCC 4740 resulted in the formation of 2alpha,6beta,13-trihydroxystemodane (2), 2alpha,3beta,13-trihydroxystemodane (3), 2alpha,11beta,13-trihydroxystemodane (4) and 2alpha,13,14-trihydroxystemodane (5), while stemodinone (7) afforded 6alpha,13-dihydroxystemodan-2-one (8) and 6alpha,12alpha,13-trihydroxystemodan-2-one (9). Metabolites obtained from the bioconversion of stemarin (11) were 8,13,19-trihydroxystemarane (12) and 2alpha,13,19-trihydroxystemarane (13). 19-N,N-Dimethylcarbamoxy-13-hydroxystemarane (14) was not transformed by the fungus. Stemodin (1) was incubated with Whetzelinia sclerotiorum ATCC 18687 to produce 2alpha,7beta,13-trihydroxystemodane (6) and 2alpha,11beta,13-trihydroxystemodane (4). Stemodinone (7) was converted to 7beta,13-dihydroxystemodan-2-one (10). Compounds 2, 4, 9, 10, 12 and 13 have not been previously reported.

The reactions of palladium(II), thallium(III) and lead(IV) trifluoroacetates with 3beta-acetoxyandrost-5-en-17-one: crystal structure of the first trifluoroacetate bridged 5,6,7-pi-allyl steroid palladium dimer.

A number of metal trifluoroacetates were reacted with the olefin 3beta-acetoxyandrost-5-en-17-one (6). Palladium(II) trifluoroacetate afforded bis[micro-trifluoroacetato(alpha-5,7-eta-3beta-acetoxyandrostenyl-17-one)palladium(II)] (20), a new ring B pi-allyl steroid-palladium complex, in quantitative yield. Thallium(III) trifluoroacetate gave 3beta-acetoxy-5alpha-hydroxy-6beta-trifluoroacetoxyandrostan-17-one (16), 3beta-acetoxy-6beta-trifluoroacetoxyandrost-4-en-17-one (9), 3beta-acetoxy-4beta-trifluoroacetoxyandrost-5-en-17-one (10), and 3beta-acetoxy-5alpha,6beta-dihydroxyandrostan-17-one (17). Lead(IV) trifluoroacetate yielded 9, 10 and 16. 3beta-Acetoxy-5alpha,6beta-bis(trifluoroacetoxy)androstan-17-one (15), a new compound, was also formed in this reaction. During the course of the lead(IV) studies the dichlorosteroid 21 and the rearranged allylic oxidation product 24 were formed. Their formation was attributed to the generation of lead(IV) chloride in the reaction. Silver(I) and copper(II) trifluoroacetates proved to be unreactive towards 6.

Microbial transformation of cadina-4,10(15)-dien-3-one, aromadendr-1(10)-en-9-one and methyl ursolate by Mucor plumbeus ATCC 4740.

The sesquiterpenes cadina-4,10(15)-dien-3-one (1) and aromadendr-1(10)-en-9-one (squamulosone) (14) along with the triterpenoid methyl ursolate (21) were incubated with the fungus Mucor plumbeus ATCC 4740. Substrates 1, 14 and ursolic acid (20) were isolated from the plant Hyptis verticillata in large quantities. M. plumbeus hydroxylated 1 at C-12 and C-14. When the iron content of the medium was reduced, however, hydroxylation at these positions was also accompanied by epoxidation of the exocyclic double bond. In total nine new oxygenated cadinanes have been obtained. Sesquiterpene 14 was converted to the novel 2alpha,13-dihydroxy derivative along with four other metabolites. Methyl ursolate (21) was transformed to a new compound, methyl 3beta,7beta,21beta-trihydroxyursa-9(11),12-dien-28-oate (22). Two other triterpenoids, 3beta,28-dihydroxyurs-12-ene (uvaol) (23) and 3beta,28-bis(dimethylcarbamoxy)urs-12-ene (24) were not transformed by the micro-organism, however.