The degraded C-21 sesterterpenoid (+)-3, enantiomeric with (-)-untenospongin B, has been isolated from the Mediterranean sponge Spongia virgultosa. The absolute stereochemistry of 3 was assigned by applying Mosher’s method. On the basis of this work, the absolute stereochemistry at C-11 of nitenin (1) and dihydronitenin (2) has been reanalyzed by applying Mosher’s method, whereas the R chirality at C-8 of 2 was determined by recording NOE spectra.The structures of two known C-21 furanoterpenes, tetradehydrofurospongin-1 (8) and 7, have been revised as (+)-3 (named “revised tetradehydrofurospongin-1”) and its acetyl derivative 5, respectively. Finally, a comparison between the Mosher and Horeau methods was carried out, paying attention to the reliability of the stereochemical predictions obtained by the two approaches applied to compounds (+)-3, nitenin (1), and dihydronitenin (2), containing aliphatic-type alcohols.
Structural and Stereochemical Studies of C-21 Terpenoids from the Mediterranean Spongiidae Sponges / Fontana, A; Albarella, L.; Scognamiglio, G.; Uriz, M. J.; Cimino, G.. - In: JOURNAL OF NATURAL PRODUCTS. - ISSN 0163-3864. - 59:(1996), pp. 869-872. [S0163-3864(96)00096-1]
Structural and Stereochemical Studies of C-21 Terpenoids from the Mediterranean Spongiidae Sponges
Fontana A;
1996
Abstract
The degraded C-21 sesterterpenoid (+)-3, enantiomeric with (-)-untenospongin B, has been isolated from the Mediterranean sponge Spongia virgultosa. The absolute stereochemistry of 3 was assigned by applying Mosher’s method. On the basis of this work, the absolute stereochemistry at C-11 of nitenin (1) and dihydronitenin (2) has been reanalyzed by applying Mosher’s method, whereas the R chirality at C-8 of 2 was determined by recording NOE spectra.The structures of two known C-21 furanoterpenes, tetradehydrofurospongin-1 (8) and 7, have been revised as (+)-3 (named “revised tetradehydrofurospongin-1”) and its acetyl derivative 5, respectively. Finally, a comparison between the Mosher and Horeau methods was carried out, paying attention to the reliability of the stereochemical predictions obtained by the two approaches applied to compounds (+)-3, nitenin (1), and dihydronitenin (2), containing aliphatic-type alcohols.File | Dimensione | Formato | |
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