Identification of Diastereomeric Cyano–Aqua Cobinamides
1
HPLC as the corresponding TFA salts. H NMR (500 MHz, [D
2
]-
vitamin B12 from DSM Nutritional Products AG (Basel/Switzer-
land) is acknowledged. This work was supported by the Swiss
National Science Foundation (Grant No. 200021–117822).
2
D O): see Supporting Information. MS (ESI-MS): m/z (%) =
+
1015.6 (100) [M – H
3.5 min (4 ).
2 t α t
O] . HPLC-UV/Vis: R = 8.8 min (4 ), R =
1
β
[
1] B. Kräutler, D. Arigoni, B. Golding, Vitamin B12 and B12-
Synthesis of 2on: Intermediate 6 was synthesized from dicyano-
cobyric acid (4.9 mg, 5.0 μmol) as described in previous work.[21]
It was dissolved in DMF (1 mL) and cooled to 0 °C, after which
DMAP (1.0 mg, 8 μmol) and 7[ (4.5 mg, 15 μmol) were added.
After 10 min, EDC·HCl (3.0 mg, 15 μmol) was added. The solution
was warmed up to room temperature. After 4 h, the solvent was
removed under reduced pressure. The residue was washed with ace-
Proteins, Wiley-VCH, Weinheim, 1998.
[2] K. L. Brown, Chem. Rev. 2005, 105, 2075–2149.
[3] T. Toraya, A. Ishida, J. Biol. Chem. 1991, 266, 5430–5437.
[4] P. Butler, M. O. Ebert, A. Lyskowski, K. Gruber, C. Kratky, B.
Krautler, Angew. Chem. Int. Ed. 2006, 45, 989–993.
21]
[5] R. Scheffold, Chimia 1985, 39, 203–211.
[6] H. Shimakoshi, M. Abiru, S. Izumi, Y. Hisaeda, Chem. Com-
mun. 2009, 6427–6429.
[7] K. Nakamura, Y. Hisaeda, L. Pan, H. Yamauchi, J. Or-
ganomet. Chem. 2009, 694, 916–921.
[
tone and further purified with preparative HPLC to afford 2on
1
(
(
3.8 mg, 2.9 μmol, 58%) as the corresponding TFA salt. H NMR
2 2
500 MHz, [D ]D O): see Supporting Information. HR-MS: calcd.
8] F. H. Zelder, C. Männel-Croise, Chimia 2009, 63, 58–62.
9] Z. Xu, X. Chen, H. N. Kim, J. Yoon, Chem. Soc. Rev. 2010,
+
for C59
H81CoN15
O
8
[M] 1186.57191; found 1186.57087. UV/Vis
[
(c = 30 μm, 0.2 m KCl, pH = 5.98): 548 nm (3.96), 521 nm (3.94),
39, 127–137.
4
1
13 nm (3.72), 361 nm (4.43), 279 nm (4.27), HPLC-UV/Vis: R
4.2 min; pKbase-off = 2.58.
t
=
[
[
[
10] J. A. Ma, P. K. Dasgupta, Anal. Chim. Acta 2010, 673, 117–
125.
11] W. Friedrich, H. Ohlms, W. Sandeck, R. Bieganow, Z. Natur-
forsch., Teil B 1967, 22, 839–850.
Synthesis of (2on + 2
1.3 mg, 20 μmol) were dissolved in water (5 mL) to obtain a violet
solution of 2αβ. The pH value of the solution was adjusted to 2
with trifluoroacetic acid. After purging the solution with N for
0 min to remove HCN, the reaction solution was adsorbed on a
α
): Compound 2on (1.3 mg, 1.0 μmol) and KCN
(
12] W. Friedrich, M. Moskophidis, Z. Naturforsch., Teil B 1968,
23, 804–812.
2
[13] J. M. Pratt (Ed.) in Inorganic Chemistry of Vitamin B12, Aca-
demic Press, New York, 1972, p. 119–124.
[14] K. L. Brown, X. Zou, J. Am. Chem. Soc. 1992, 114, 9643–9651.
[
2
®
reverse-phase Chromafix C18ec cartridge. It was washed with
water (30 mL) and then eluted with MeOH (3 mL). The solvent
15] K. L. Brown, X. Zou, L. Salmon, Inorg. Chem. 1991, 30, 1949–
1953.
was removed under vacuum to yield 2on and 2
α
as a mixture of the
[
[
[
16] K. L. Brown, J. M. Hakimi, Inorg. Chem. 1984, 23, 1756–1764.
17] C. Männel-Croise, F. Zelder, Inorg. Chem. 2009, 48, 1272–1274.
18] S. S. M. Hassan, M. S. A. Hamza, A. E. Kelany, Talanta 2007,
corresponding TFA salts (1.3 mg, 100%). ESI-MS: m/z (%) =
+
1
186.6 (100) [M]+ for 2on or [M – H
2 α
O] for 2 .
7
1, 1088–1095.
19] M. K. Freeman, L. G. Bachas, Anal. Chim. Acta 1990, 241,
19–125.
Synthesis of (1on + 1 ): The synthesis and separation was performed
α
[
[
[
[
[
[
as described for the synthesis of (2on + 2 ) starting from 1αβ. The
UV/Vis spectrum of (1on + 1 ) is shown in Figure 2 (top).
α
1
α
20] C. Männel-Croise, B. Probst, F. Zelder, Anal. Chem. 2009, 81,
Supporting Information (see footnote on the first page of this arti-
cle): Materials and methods, the general atom numbering of B12
9493–9498.
21] K. Zhou, F. Zelder, Angew. Chem. Int. Ed. 2010, 49, 5178–
5180.
α
derivatives, the synthesis of Cbl and Cblon, and NMR chemical
22] F. H. Zelder, C. Buchwalder, R. M. Oetterli, R. Alberto, Chem.
Eur. J. 2010, 16, 6155–6158.
shifts for 2on, 4 , and 4
α
β
.
23] W. W. Reenstra, W. P. Jencks, J. Am. Chem. Soc. 1979, 101,
5780–5791.
Acknowledgments
24] R. A. Firth, H. A. O. Hill, J. M. Pratt, R. G. Thorp, J. Chem.
Soc. A 1968, 453–456.
The authors thank L. Bigler for the recording of the HR-ESI-MS
spectra and R. Alberto for helpful discussions. A generous gift of
Received: October 26, 2010
Published Online: November 26, 2010
Eur. J. Inorg. Chem. 2011, 53–57
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
57