Galanthamine and Codeine Probes
G
(2 equiv.) and sodium bicarbonate (6 equiv.) to give a yellow
20
Reactions were carried out in 10 mM 4-(2-hydroxyethyl)
piperazine-1-ethanesulfonic acid (HEPES) buffer solution
adjusted to pH 7.5 at 208C. A solution of the enone (1 equiv.)
was mixed with a solution of N-acetyl-L-cysteine methyl ester
(20 equiv.), and the composition of the mixture was analyzed by
LCMS at regular intervals. The concentration of the enone at
each interval was determined with reference to a calibration
curve, and the pseudo-first order rate constant for the reaction
was estimated by least-squares curve fitting of the plot of enone
concentration against time using KaleidaGraph.
oil, ½aꢀD þ31 (c 1.0 in CHCl3), which was purified by flash
chromatography (9 : 1 chloroform/methanol) to yield the title
compound 21 (14 mg, 44 %) as a white solid, mp 90–928C.
20
½aꢀD þ23 (c 1.0 in CHCl3).
Narwedine-N-Acetyl-L-cysteine Methyl Ester Adducts
The general procedure was applied to narwedine (4, 50 mg,
175 mmol), and after purification by flash chromatography
(9 : 1 chloroform/methanol), adduct 23a (or 23b) (31 mg, 38 %)
and adduct 23b (or 23a) (35 mg, 43 %) were obtained as
colourless oils.
Investigation of Reaction Kinetics by 1H NMR
Reactions were carried out in deuterated methanol at 258C.
A solution of the enone (1 equiv.) was mixed with a solution of
N-acetyl-L-cysteine methyl ester (20 equiv.), and the composi-
Adduct 23a (or 23b)
20
½aꢀD þ3 (c 0.4 in CHCl3). nmax (NaCl)/cmꢁ1 3289, 1744,
1
tion of the mixture was determined by H NMR analysis at
1721, 1675, 1286, 1204. dH (CDCl3, 800 MHz) 6.68 (1H, d,
0
J 8.0, H2), 6.64 (1H, d, J 8.0, H1), 6.29 (1H, d, br, J 7.6, H3 ), 4.86
regular intervals. The concentration of the enone at each interval
was determined by comparing the relative integration of the H7
olefinic proton in the starting material with the H12b benzylic
proton in both the starting material and product. The pseudo-first
order rate constant for the reaction was estimated by least-
squares curve fitting of the plot of enone concentration against
time using KaleidaGraph.
0
(1H, ddd, J 7.6, 5.6, 4.0, H2 ), 4.68 (1H, t, J 2.8, H4a), 4.11 (1H, d,
0
J 14.8, H12b), 3.83 (3H, s, H3a), 3.78 (3H, s, H1a ), 3.63 (1H, d,
J 14.8, H12a), 3.58 (1H, s, br, H8), 3.41 (1H, t, br, J 13.6, H10b),
0
3.14 (1H, dd, J 13.6, 4.0, H2a ), 3.10 (1H, d, br, J 14.4, H10a),
2.98–3.01 (1H, m, H5b), 2.94–2.96 (1H, m, H5a), 2.88 (1H, dd,
0
J 13.6, 5.6, H2a ), 2.58 (1H, dd, J 16.8, 3.6, H7b), 2.50 (1H, dd,
J 16.8, 2.8, H7a), 2.32 (3H, s, H11a), 2.09 (1H, t, br, J 14.0, H9a),
0
2.07 (3H, s, H3b ), 1.96 (1H, dd, J 14.0, 3.2, H9b). dC (CDCl3,
Supplementary Material
100 MHz) 206.3, 171.1, 170.0, 146.8, 144.0, 131.7, 129.5,
123.0, 111.7, 87.9, 60.0, 56.1, 55.3, 53.0, 51.7, 51.4, 44.3,
41.8, 41.1, 40.2, 33.9, 32.8, 23.2. m/z (EI) 462 (,1 %, [M]þꢄ),
286 (35), 285 (100, [M ꢁ C6H11NO3S]þꢄ), 242 (40), 216 (25),
199 (25), 174 (45), 118 (20), 88 (45), 76 (50). m/z (HRMS ESI)
463.1904; [M þ H]þ requires 463.1903.
Experimental procedures for compounds 4–7, 9, 10, 13, 15–19,
1H NMR and 13C NMR spectra for all compounds, and low-
resolution mass spectra for new compounds are available on the
Journal’s website.
Acknowledgements
We thank Tasmanian Alkaloids for the generous supply of codeine
and morphine and Janssen Pharmaceutica for the generous supply of
galanthamine hydrobromide. We thank Dr Sam Bailey and Dr Robert
Rezaie from Tasmanian Alkaloids for helpful discussions and Professor
Gottfried Otting from the Australian National University for assistance
with NMR analysis.
Adduct 23b (or 23a)
20
½aꢀD þ50 (c 0.4 in CHCl3). nmax (NaCl)/cmꢁ1 3271, 1720,
1659, 1286, 1204. dH (CDCl3, 800 MHz) 6.69 (1H, d, J 8.0, H2),
0
6.64 (1H, d, J 8.0, H1), 6.19 (1H, d, J 7.6, H3 ), 4.78 (1H, td, J 7.6,
0
4.0, H2 ), 4.69 (1H, t, J 2.8, H4a), 4.19 (1H, d, J 14.8, H12b), 3.84
0
(3H, s, H3a), 3.77 (3H, s, H1a ), 3.67 (1H, s, br, H8), 3.63 (1H, d,
J 14.8, H12a), 3.39 (1H, t, br, J 13.2, H10b), 3.15 (1H, dd, J 13.6,
0
4.0, H2a ), 3.09 (1H, d, br, J 14.4, H10a), 3.03 (1H, dd, J 18.4, 2.8,
H5a), 2.95 (1H, dd, J 18.4, 2.8, H5b), 2.78 (1H, dd, J 13.6, 7.6,
0
H2a ), 2.61 (1H, dd, J 17.2, 3.6, H7b), 2.52 (1H, dd, J 17.2, 2.8,
0
H7a), 2.34 (3H, s, H11a), 2.08–2.12 (4H, m, H9a, H3b ), 1.98 (1H,
References
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Investigation of Reaction Kinetics by LCMS
The enones and their adducts with N-acetyl-L-cysteine methyl
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an Agilent C18 column (50 mm with a 5 mm guard column,
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.
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