(3H, s, 132-COOCH3), 3.71 (3H, s, 18-CH3), 3.68 (3H, s, 2-CH3),
3.52 (3H, s, 7-CH3) and 1.83 (3H, t, J = 7.8 Hz, 81-CH3) [172-
COOH was not identified due to the fast exchange with a trace
contaminant H2O in the solvent]; dC(150 MHz; THF-d8; Me4Si)
188.8 (C131), 170.6 (C133), 167.1 (C173), 158.3 (C14 or C16), 152.3
(C6), 151.9 (C11), 149.4 (C19), 149.2 (C9), 149.1, 149.0, 143.6 (C1,
C4 and C14 or C16), 144.6 (C8), 141.5 (C18), 138.8 (C171), 138.4
(C2), 138.1 (C3), 136.3 (C7), 135.5 (C13), 135.0 (C12), 134.7 (C17),
130.9 (C31), 123.8 (C172), 118.7 (C32), 112.4 (C15), 101.5 (C10),
98.2 (C20), 97.9 (C5), 67.9 (C132), 51.6 (C134), 19.5 (C81), 17.2
(C82), 12.9 (C181), 12.1 (C21), 11.9 (C121) and 10.6 (C71); m/z
(ESI) 611.3 (MH+).
trans to 31-H), 6.09 (1H, d, J = 11.3 Hz, 32-H cis to 31-H), 5.64
(1H, t, J = 6.7 Hz, phytyl 2-H), 4.94 (2H, m, phytyl 1-H2), 4.03
(2H, q, J = 7.6 Hz, 8-CH2), 3.85 (3H, s, 12-CH3), 3.77 (3H, s,
132-COOCH3), 3.73 (3H, s, 18-CH3), 3.70 (3H, s, 2-CH3), 3.54
(3H, s, 7-CH3), 2.14 (2H, m, phytyl 4-H2), 1.89 (3H, s, phytyl 3-
CH3), 1.84 (3H, t, J = 7.7 Hz, 81-CH3), 1.61–1.06 (18H, m, phytyl
5-, 6-, 8-, 9-, 10-, 12-, 13-, 14-H2, 7-, 11-H), 1.52 (1H, m, phytyl
15-H), 0.92, 0.87 (each 3H, d, J = 6.5 Hz, phytyl 7-, 11-CH3) and
0.86 (6H, d, J = 6.5 Hz, phytyl 15-CH3, 16-H3) [the numbering of
phytyl protons corresponded to that in Scheme 1(a)]; m/z (FAB)
888.5063 (M+. C55H68N4O5Mg requires 888.5040).
Chl-c2-phy.
max(THF)/cm-1 1738 (ester-C O) and 1707 (keto-
=
n
=
C O); lmax(THF)/nm 635 (relative intensity, 0.07), 589 (0.11) and
460 (1.00); dH(600 MHz; THF-d8; Me4Si) 10.25 (1H, s, 10-H),
10.08 (1H, s, 5-H), 10.08 (1H, s, 20-H), 9.18 (1H, d, J = 15.8 Hz,
171-H), 8.39 (2H, dd, J = 11.6, 17.8 Hz, 31-, 81-CH), 7.04 (1H, s,
132-H), 6.80 (1H, d, J = 15.8 Hz, 172-H), 6.40 (1H, d, J = 17.4 Hz,
32-H trans to 31-H), 6.38 (1H, d, J = 17.5 Hz, 82-H trans to 81-H),
6.10, 6.09 (each 1H, d, J = 11.4 Hz, 32-, 82-H cis to 31-, 81-H), 5.63
(1H, t, J = 7.0 Hz, phytyl 2-H), 4.94 (2H, m, phytyl 1-H2), 3.85
(3H, s, 12-CH3), 3.78 (3H, s, 132-COOCH3), 3.74 (3H, s, 18-CH3),
3.71 (3H, s, 2-CH3), 3.65 (3H, s, 7-CH3), 2.14 (2H, m, phytyl 4-H2),
1.89 (3H, s, phytyl 3-CH3), 1.62–1.07 (18H, m, phytyl 5-, 6-, 8-,
9-, 10-, 12-, 13-, 14-H2, 7-, 11-H), 1.52 (1H, m, phytyl 15-H), 0.92,
0.87 (each 3H, d, J = 6.5 Hz, 7-, 11-H3) and 0.86 (6H, d, J =
6.5 Hz, phytyl 15-CH3, 16-H3) [the numbering of phytyl protons
corresponded to that in Scheme 1(a)]; m/z (FAB) 886.4853 (M+.
C55H66N4O5Mg requires 886.4884).
Chl-c2.
lmax(THF)/nm 634 (relative intensity, 0.08), 587 (0.11)
and 458 (1.00); dH(600 MHz; THF-d8; Me4Si) 10.21 (1H, s,
10-H), 10.07 (1H, s, 5-H), 10.03 (1H, s, 20-H), 9.10 (1H, d, J =
16.0 Hz, 171-H), 8.39 (2H, dd, J = 11.5, 17.9 Hz, 31-, 81-H), 6.98
(1H, s, 132-H), 6.74 (1H, d, J = 16.0 Hz, 172-H), 6.41 (1H, d,
J = 18.2 Hz, 32-H trans to 31-H), 6.38 (1H, d, J = 17.9 Hz, 82-H
trans to 81-H), 6.11 (1H, d, J = 10.9 Hz, 32-H cis to 31-H), 6.09
(1H, d, J = 11.2 Hz, 82-H cis to 81-H), 3.84 (3H, s, 12-CH3), 3.79
(3H, s, 132-COOCH3), 3.73 (3H, s, 18-CH3), 3.71 (3H, s, 2-CH3)
and 3.69 (3H, s, 7-CH3) [172-COOH was not identified due to
the fast exchange with a trace contaminant H2O in the solvent];
dC(150 MHz; THF-d8; Me4Si) 188.8 (C131), 170.5 (C133), 167.1
(C173), 158.5 (C14 or C16), 152.0 (C11), 151.3 (C6), 149.5 (C19),
149.3 (C1), 148.9, 148.4, 144.0 (C4, C9 and C14 or C16), 141.8
(C18), 138.8 (C8), 138.7 (C171), 138.4 (C2), 138.3 (C3), 137.5 (C7),
135.64, 135.60 (C12 and C13), 134.9 (C17), 130.94 (C81), 130.88
(C31), 123.9 (C172), 118.83, 118.77 (C32, C82), 112.4 (C15), 102.5
(C10), 98.4 (C5), 98.3 (C20), 67.8 (C132), 51.6 (C134), 12.9 (C181),
12.12 (C71), 12.08 (C21) and 11.98 (C121); m/z (ESI) 609.2 (MH+).
Synthesis of PChls-a (propionate-type derivatives)
As reported earlier, Chl-a was extracted from Spirulina geitleri.27
The C17–C18 single bond in Chl-a was quantitatively oxidized
with DDQ in acetone to afford protochlorophyll (PChl)-a, ac-
cording to reported procedures.22 DDQ in acetone (ca. 9 mM)
was added to an acetone solution (10 mL) of Chl-a(/a¢) (~8 :
2, 20 mg) and the mixture was stirred at room temperature.
After disappearance of the 661 nm peak characteristic of the
chlorin moiety, the reaction mixture was extracted with CH2Cl2
and aqueous 1% (wt/v) KHSO4. The organic phase was washed
with aqueous 4% (wt/v) NaHCO3 and distilled water, dried over
anhydrous Na2SO4, filtered, and concentrated. The residue was
purified by chromatography on silica gel (Wakogel C-300, 2–5%
(v/v) acetone in CH2Cl2) and recrystallized from hexane, yielding
an enantiomeric mixture of PChl-a as a green solid (16 mg,
Synthesis of Chls-c-phy (acrylate-type derivatives)
1-Bromo-3,7,11,15-tetramethylhexadec-2-ene (phytyl bromide)
was synthesized according to reported methods.20 Phosphorus
tribromide (72 mL) was added to a solution of phytol (Z + E)
(460 mg) in hexane (5 mL) at 0 ◦C. The mixture was stirred
under N2 gas for 10 min, and then methanol (0.2 mL) was added
and further stirred for 5 min. The reaction mixture was washed
with aqueous 4% (wt/v) NaHCO3 and distilled water, dried over
anhydrous MgSO4, and concentrated. The crude product was used
in the following step.
Chl-c1 was esterified with phytyl bromide similarly to reported
procedures.21 Crude phytyl bromide (30 mg) and CsF (8.1 mg)
were added to a solution of Chl-c1 (16 mg) in DMF (5 mL). The
mixture was stirred under N2 gas overnight. The reaction mixture
was washed with aqueous saturated NaCl and distilled water,
dried over anhydrous Na2SO4, and concentrated. The residue
was purified by silica gel chromatography (Wakogel C-300, 3–
5% acetone in CH2Cl2) to give Chl-c1-phy in 91% yield. Chl-c2 was
also esterified by the same method (86%).
80%): nmax(THF)/cm-1 1740 (ester-C O) and 1703 (keto-C O);
max(THF)/nm 628 (relative intensity, 0.12), 577 (0.05) and 442
=
=
l
(1.00); dH(600 MHz; THF-d8; Me4Si) 10.10 (1H, s, 10-H), 9.98
(1H, s, 5-H), 9.92 (1H, s, 20-H), 8.37 (1H, dd, J = 11.5, 17.7 Hz,
31-H), 7.02 (1H, s, 132-H), 6.39 (1H, d, J = 17.8 Hz, 32-H trans
to 31-H), 6.08 (1H, d, J = 11.3 Hz, 32-H cis to 31-H), 5.33 (1H,
t, J = 6.5 Hz, phytyl 2-H), 4.60 (2H, d, J = 6.8 Hz, phytyl 1-
H2), 4.19, 4.11 (each 1H, m, 17-CH2), 4.04 (2H, q, J = 7.6 Hz,
8-CH2), 3.87 (3H, s, 12-CH3), 3.73 (3H, s, 132-COOCH3), 3.69
(3H, s, 2-CH3), 3.56 (3H, s, 18-CH3), 3.55 (3H, s, 7-CH3), 3.10,
2.92 (each 1H, m, 171-CH2), 1.99 (2H, m, phytyl 4-H2), 1.85 (3H,
t, J = 7.6 Hz, 81-CH3), 1.68 (3H, s, phytyl 3-CH3), 1.52 (1H, m,
phytyl 15-H), 1.47–1.02 (18H, m, phytyl 5-, 6-, 8-, 9-, 10-, 12-,
13-, 14-H2, 7-, 11-H) and 0.86 (12H, d, J = 6.5 Hz, phytyl 7-, 11-,
Chl-c1-phy.
max(THF)/cm-1 1738 (ester-C O) and 1707 (keto-
=
n
=
C O); lmax(THF)/nm 633 (relative intensity, 0.10), 586 (0.10) and
457 (1.00); dH(600 MHz; THF-d8; Me4Si) 10.08 (1H, s, 10-H),
10.03 (1H, s, 20-H), 9.99 (1H, s, 5-H), 9.16 (1H, d, J = 16.1 Hz,
171-H), 8.37 (1H, dd, J = 11.3, 17.8 Hz, 31-H), 7.01 (1H, s, 132-H),
6.78 (1H, d, J = 15.8 Hz, 172-H), 6.40 (1H, d, J = 17.9 Hz, 32-H
This journal is
The Royal Society of Chemistry 2009
Org. Biomol. Chem., 2009, 7, 2120–2126 | 2125
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