9, 10-Secocholesta-(5Z)-5,8(14), 10(19)-trien-3β-ol und 18-Nor-14β-methyl-9,10-secocholesta-(5E)-5, 10(19), 13(17)-trien-3β-ol,zwei neue Doppelbindungsisomere des Vitamins D3. Strukturelle Abwandlungen am Vitamin D3: 5. Mitteilung [1]

9,10-Secocholesta-(5 Z )-5,8(14),10(19)-triene-3β-ol and 18-Nor-14β-methyl-9,10-secocholesta-(5 E )-5,10(19), 13(17)-trien-3β-ol, two new double bond isomers of vitamin D₃ . Structural modifications of vitamin D₃: 5. Communication [1] The present paper reports the synthesis and structure elucidation of the two title compounds. Treatment of the 4-phenyl-1,2,4-triazolin-3,5-dione adducts of vitamin D₃ with BF₃O (C₂H₅)₂ and KOH/butanol yields these two new vitamin D₃ double bond isomers.     

Ergosta-5,7,9(11), 22-tetraen-3β-ol and its 24ξ-Ethyl Homolog,Two New Marine Sterols from the Red Sea Sponge Biemna fortis

The steroidal components of a Red Sea sponge, Biemna fortis, were fractionated through reversed phase HPLC. and analyzed by a combination of physical methods, including high resolution GC./MS. and 360 MHz ¹H-NMR. The sponge contains five conventional Δ⁵-sterols, 1a – c , 1e , 1g , which comprise about 25% of the mixture and 2,5% of gorgosterol (1h) , a sterol never found before in Porifera. Three Δ^5,7,22-sterols were also present as major components in the mixture (～70%): cholesta-5,7,22-trien-3β-ol (2a) , ergosta-5,7,22-trien-3β-ol (2c) and (24R)-ethylcholesta-5,7,22-trien-3β-ol (2e) whereas two new tetra-unsaturated sterols were identified in minor amounts (2%): ergosta-5,7,9(11),22-tetraen-3β-ol (3c) and 24ξ-ethylcholesta-5,7,9 (11), 22-tetraen-3β-ol ( 3e or 3f ). NMR. spectroscopy made possible the assignment of a 24R configuration for all the C(24) substituted sterols isolated in sufficient amount from the mixture. The possible symbiotic, dietary or biosynthetic origins of these sterols are discussed.     

Conformations of the Ten-membered Ring in 5, 10-Secosteroids. III: (Z)-3β- and (Z)-3α-Hydroxy-5, 10-seco-1 (10)-cholesten-5-one Esters and (Z)-5, 10-seco-1 (10)-Cholestene-3, 5-dione

(Z)-3β-Acetoxy- and (Z)-3 α-acetoxy-5, 10-seco-1 (10)-cholesten-5-one ( 6a ) and ( 7a ) were synthesized by fragmentation of 3β-acetoxy-5α-cholestan-5-ol ( 1 ) and 3α-acetoxy-5β-cholestan-5-ol ( 2 ), respectively, using in both cases the hypoiodite reaction (the lead tetraacetate/iodine version). The 3β-acetate 6a was further transformed, via the 3β-alcohol 6d to the corresponding (Z)-3β-p-bromobenzoate ester 6b and to (Z)-5, 10-seco-1 (10)-cholestene-3, 5-dione ( 8 ) (also obtainable from the 3α-acetate 7a ). The ¹H-and ¹³C-NMR. spectra showed that the (Z)-unsaturated 10-membered ring in all three compounds ( 6a , 7a and 8 ) exists in toluene, in only one conformation of type C ₁, the same as that of the (Z)-3β-p-bromobenzoate 6b in the solid state found by X-ray analysis. The unfavourable relative spatial factors (interdistance and mutual orientation) of the active centres in conformations of type C ₁ are responsible for the absence of intramolecular cyclizations in the (Z)-ketoesters 6 and 7 ( a and c ).     

Minor and Trace Sterols in Marine Invertebrates. XII. Occurrence of 24 (R + S)-isopropenylcholesterol, 24 (R + S)-methylcholesta-5, 25-dien-3β-ol,and 24 (R + S)-methylcholesta-7, 25-dien-3β-ol in the caribbean sponge,Verongia cauliformis

In addition to the two new sterols verongulasterol 11 and 25-dehydroaplysterol 13 of Verongia cauliformis³), which were reported earlier [2] [3], the minor and trace sterols of this sponge include five new sterols listed in the title (with the exception of the known 24 S-methyl-cholesta-5, 25-dien-3β-ol (codisterol, 1b ). The isolation of the 24(R)-epimer of codisterol is of interest, as this compound is a possibly biosynthetic precursor for aplysterol 12 , 25-dehydroaplysterol 13 , and verongulasterol 11 (all 24R) which occur in the same sponge [2]. A partial synthesis from fucosterol ( 4 ) of 24 (R + S)-isopropenylcholesterol ( 9 ), and of 24-isopropylcholesterol ( 10 ) is described.     

5-(α-Fluorovinyl)tryptamines and 5-(α-Fluorovinyl)-3-(N-methyl-1′,2′,5′,6′,-tetrahydropyridin-3′- and -4′-yl)indoles—5-(α-Fluorovinyl)tryptamines

5-(α-Fluorovinyl)tryptamines 4a, 4b and 5-(α-fluorovinyl)-3-(N-methyl-1′,2′,5′,6′-tetrahydropyridin-3′- and -4′-yl) indoles 5a, 5b were synthesized using 5-(α-fluorovinyl)indole ( 7 ). The target compounds are bioisosteres of 5-carboxyamido substituted tryptamines and their tetrahydropyridyl analogs.     

Enzymatic kinetic resolution of 1-(3′-furyl)-3-buten-1-ol and 2-(2′-furyl)-propan-1-ol

The enzymatic kinetic resolution of the racemic alcohols 1-(3′-furyl)-3-buten-1-ol (±)-1 and 2-(2′-furyl)propan-1-ol (±)-2 was investigated by screening a range of lipases and esterases for enantioselective transacylation, as well as for enantioselective hydrolysis. For both alcohols, lipase-catalyzed hydrolysis of the derived racemic acetate gave the best results for accessing the desired (S)-enantiomers. In the case of the secondary alcohol (±)-1, ASL turned out to be the optimum enzyme, whereas PPL was found to be superior in the case of the primary alcohol (±)-2. Additionally, an alternative access to (S)-2 via Oppolzer's camphor sultam methodology is described.