Abstract
Six novel polybrominated biindole derivatives have been isolated from the marine blue-green alga Rivularia firma: 2,2′,5,5′-tetrabromo-3,3′-bi-1H-indole (1), (+)-2,3′,5,5′-tetrabromo-7′-methoxy-3,4′-bi-1H-indole (2), (+)-3′,5,5′-tribromo-7′-methoxy-3,4′-bi-1H-indole (3), (+)-2,5,5′-tribromo-7′-methoxy-3,4′-bi-1H-indole (4), (−)-3,3′,5,5′-tetrabromo-7′-methoxy-1,4′-bi-1H-indole (5), and (+)-2,2′,3,4′,5,5′-hexabromo-1,3′-bi-1H-indole (6). Structures were solved by analysis of 1H and 13C chemical shifts, 13C-1H coupling constants, and 13C spin-lattice relaxation data (at 15.04 MHz). The contributions of 13C-1H dipolar interactions to the spin-lattice relaxation times (T1) of quaternary carbons were determined from measured T1 and nuclear Overhauser enhancement values and then used to estimate the numbers of protons two bonds removed from each quaternary carbon. This information was used in structure determination as well as for resonance assignments. Spin-lattice relaxation data were also used to identify brominated carbons. The biindoles 2–6 are optically active and are therefore new representatives of a very small number of natural products in which chirality is due solely to restricted rotation.
| Original language | English |
|---|---|
| Pages (from-to) | 3628-3635 |
| Number of pages | 8 |
| Journal | Journal of the American Chemical Society |
| Volume | 104 |
| Issue number | 13 |
| DOIs | |
| Publication status | Published - 1982 |
| Externally published | Yes |
Cite this
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A Series of Chiral Polybrominated Biindoles from the Marine Blue-Green Alga Rivularia firma. Application of 13C NMR Spin-Lattice Relaxation Data and 13C-1H Coupling Constants to Structure Elucidation. / Norton, Raymond S.; Wells, Robert J.
In: Journal of the American Chemical Society, Vol. 104, No. 13, 1982, p. 3628-3635.Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - A Series of Chiral Polybrominated Biindoles from the Marine Blue-Green Alga Rivularia firma. Application of 13C NMR Spin-Lattice Relaxation Data and 13C-1H Coupling Constants to Structure Elucidation
AU - Norton, Raymond S.
AU - Wells, Robert J.
PY - 1982
Y1 - 1982
N2 - Six novel polybrominated biindole derivatives have been isolated from the marine blue-green alga Rivularia firma: 2,2′,5,5′-tetrabromo-3,3′-bi-1H-indole (1), (+)-2,3′,5,5′-tetrabromo-7′-methoxy-3,4′-bi-1H-indole (2), (+)-3′,5,5′-tribromo-7′-methoxy-3,4′-bi-1H-indole (3), (+)-2,5,5′-tribromo-7′-methoxy-3,4′-bi-1H-indole (4), (−)-3,3′,5,5′-tetrabromo-7′-methoxy-1,4′-bi-1H-indole (5), and (+)-2,2′,3,4′,5,5′-hexabromo-1,3′-bi-1H-indole (6). Structures were solved by analysis of 1H and 13C chemical shifts, 13C-1H coupling constants, and 13C spin-lattice relaxation data (at 15.04 MHz). The contributions of 13C-1H dipolar interactions to the spin-lattice relaxation times (T1) of quaternary carbons were determined from measured T1 and nuclear Overhauser enhancement values and then used to estimate the numbers of protons two bonds removed from each quaternary carbon. This information was used in structure determination as well as for resonance assignments. Spin-lattice relaxation data were also used to identify brominated carbons. The biindoles 2–6 are optically active and are therefore new representatives of a very small number of natural products in which chirality is due solely to restricted rotation.
AB - Six novel polybrominated biindole derivatives have been isolated from the marine blue-green alga Rivularia firma: 2,2′,5,5′-tetrabromo-3,3′-bi-1H-indole (1), (+)-2,3′,5,5′-tetrabromo-7′-methoxy-3,4′-bi-1H-indole (2), (+)-3′,5,5′-tribromo-7′-methoxy-3,4′-bi-1H-indole (3), (+)-2,5,5′-tribromo-7′-methoxy-3,4′-bi-1H-indole (4), (−)-3,3′,5,5′-tetrabromo-7′-methoxy-1,4′-bi-1H-indole (5), and (+)-2,2′,3,4′,5,5′-hexabromo-1,3′-bi-1H-indole (6). Structures were solved by analysis of 1H and 13C chemical shifts, 13C-1H coupling constants, and 13C spin-lattice relaxation data (at 15.04 MHz). The contributions of 13C-1H dipolar interactions to the spin-lattice relaxation times (T1) of quaternary carbons were determined from measured T1 and nuclear Overhauser enhancement values and then used to estimate the numbers of protons two bonds removed from each quaternary carbon. This information was used in structure determination as well as for resonance assignments. Spin-lattice relaxation data were also used to identify brominated carbons. The biindoles 2–6 are optically active and are therefore new representatives of a very small number of natural products in which chirality is due solely to restricted rotation.
UR - http://www.scopus.com/inward/record.url?scp=0001673644&partnerID=8YFLogxK
U2 - 10.1021/ja00377a014
DO - 10.1021/ja00377a014
M3 - Article
AN - SCOPUS:0001673644
VL - 104
SP - 3628
EP - 3635
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 13
ER -