Efficient synthesis of 4-methylumbelliferyl dihydroferulate

Article abstract of DOI:10.1081/SCC-120013746

A convenient four-step synthesis of 4-methylumbelliferyl dihydroferulate, starting from ferulic acid and 4-methylumbelliferone is described.

Full text of DOI:10.1081/SCC-120013746

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EFFICIENT SYNTHESIS OF 4-METHYL- UMBELLIFERYL
DIHYDROFERULATE
Andrés Leschot a , Ricardo A. Tapia b & Jaime Eyzaguirre a
a Facultad de Ciencias Biológicas , Departamento de Genética Molecular y Microbiología ,
Pontificia Universidad Católica de Chile , Casilla 306, Santiago 22, Chile
b Facultad de Química , Departamento de Química , Orgánica , Pontificia Universidad
Católica de Chile , Casilla 306, Santiago 22, Chile
Published online: 16 Aug 2006.
To cite this article: Andrés Leschot , Ricardo A. Tapia & Jaime Eyzaguirre (2002) EFFICIENT SYNTHESIS OF 4-METHYL-
UMBELLIFERYL DIHYDROFERULATE, Synthetic Communications: An International Journal for Rapid Communication of Synthetic
Organic Chemistry, 32:20, 3219-3223, DOI: 10.1081/SCC-120013746
To link to this article: http://dx.doi.org/10.1081/SCC-120013746
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SYNTHETIC COMMUNICATIONS
Vol. 32, No. 20, pp. 3219–3223, 2002
EFFICIENT SYNTHESIS OF 4-METHYL-
UMBELLIFERYL DIHYDROFERULATE
Andres Leschot,2 Ricardo A. Tapia,1,
*
and Jaime Eyzaguirre2
1Facultad de Quımica, Departamento de Quımica,
2
Organica, and Facultad de Ciencias Biologicas,
Departamento de Genetica Molecular y Microbiologıa,
Pontificia Universidad Catolica de Chile, Casilla 306,
Santiago 22, Chile
ABSTRACT
A convenient four-step synthesis of 4-methylumbelliferyl
dihydroferulate, starting from ferulic acid and 4-methylum-
belliferone is described.
Xylan, a polysaccharide component of plant cell walls, is one of the
most abundant biomolecules on earth. It is composed of a linear chain of
b-1,4-linked xylose residues substituted (depending on its source) with
acetate, methyl glucuronate and/or L-arabinose. The arabinose itself forms
ester linkages with cinnamoyl (feruloyl or coumaroyl) residues.[1] The bio-
degradation of xylan is a complex process with the participation of a
number of glycanases and esterases.[2]
*Corresponding author. E-mail: rtapia@puc.cl
3219
DOI: 10.1081/SCC-120013746
Copyright & 2002 by Marcel Dekker, Inc.
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3220
LESCHOT, TAPIA, AND EYZAGUIRRE
Among the esterases is the feruloyl/coumaroyl esterase which
hydrolyzes the linkage between the arabinose and the cinnamoyl residue.[3]
The activity assay for this enzyme is performed mainly following the libera-
tion by HPLC of ferulic/coumaric acid from synthetic substrates like
methyl- or ethyl cinnamates.[4] The present work describes the chemical
synthesis of 4-methylumbelliferyl dihydroferulate, a potential substrate for
the enzyme. Its hydrolysis liberates 4-methylumbelliferone, which can be
easily followed fluorimetrically.
The synthesis of 4-methylumbelliferyl dihydroferulate 6 requires an
efficient protection–deprotection method to avoid side reactions of the
phenolic hydroxyl group of 4-hydroxy-3-methoxycinnamic acid (ferulic
acid) 1. First we examined the preparation of compound 6 through acetyl-
ferulic acid,[5] but the selective hydrolysis in the last step gave low yield; there-
fore a benzyl protecting group[6,7] was used as shown in Sch. 1. Ferulic acid 1
was alkylated with benzylbromide and potassium carbonate in dimethylform-
amide to give benzyl O-benzylferulate 2 in 91% yield. Saponification of
ester 2 with potassium hydroxide in methanol–water (9 : 1) afforded the
protected O-benzylferulic acid 3 (87%). Reaction of O-benzylferulic acid 3
with thionyl chloride in toluene, followed by treatment of the acid chloride 4
with 7-hydroxy-4-methylcoumarin (4-methylumbelliferone) afforded ester 5
in 82% yield. Removal of the benzyl group and reduction of the double bond
of 5 was achieved by hydrogenation in chloroform at room temperature using
Pd/C 10% to give 4-methylumbelliferyl dihydroferulate 6 in 92% yield.
The product 6 was tested, and it is a good substrate of a purified
feroloyl/coumaroyl esterase from Penicillium purpurogenum.[8]
EXPERIMENTAL
Melting points were determined on a Kofler apparatus and are not
corrected. IR spectra were obtained on a Bruker Vector 22 spectropho-
1
tometer. H and 13C NMR spectra were recorded on a Bruker AM-200
spectrometer, using tetramethylsilane as internal reference. Column
chromatography separations were performed on Merck silica gel 60
(70–230 mesh). Elemental analyses were carried out on a FISONS EA
1108 CHNS-O analyzer.
Benzyl O-benzylferulate (2): A mixture of ferulic acid 1 (1.20 g,
6.19 mmol), potassium carbonate (3.40 g, 24.6 mmol) in DMF (6.0 mL)
was stirred for 15 min at room temperature. Benzylbromide (4.8 mL,
40.4 mmol) was added dropwise and the reaction mixture was stirred for
4 h and 80ꢀC, cooled to room temperature and quenched with water
(5.0 mL). The pH was adjusted to 4.0 with 5% HCl and the mixture was

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4-METHYLUMBELLIFERYL DIHYDROFERULATE
3221
Scheme 1.
extracted with ethyl acetate (3 ꢁ 20 mL). The combined organic phases were
washed with saturated sodium bicarbonate (20 mL) and brine (20 mL), dried
and evaporated. The residue was recrystallized from ethyl acetate–hexane to
give 2.10 g (91%) of ester 2, m.p. 89–90ꢀC; IR (KBr): 1700 (C¼O), 1630
1
(C¼C) cmꢂ1; H NMR (CDCl3): ꢀ 3.90 (s, 3H, OCH3), 5.18 (s, 2H, CH2),
5.25 (s, 2H, CH2), 6.36 (d, 1H, J ¼ 15.9 Hz, ¼CH), 6.86, (d, 1H, J ¼ 8.1 Hz,
ArH), 6.95–7.15 (m, 2H, ArH), 7.20–7.50 (m, 10H, ArH), 7.66 (d, 1H,
J ¼ 15.9 Hz, ¼CH); 13C NMR (CDCl3): ꢀ 56.0, 66.3, 70.9, 110.3, 113.5,
115.7, 122.2, 127.2, 127.7, 128.0, 128.3, 128.7, 136.2, 136.6, 145.1, 149.8,

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3222
LESCHOT, TAPIA, AND EYZAGUIRRE
150.4, 167.0. Anal. Calcd. for C24H22O4: C, 76.99; H, 5.92. Found: C, 77.03;
H, 5.96.
O-Benzylferulic acid (3): A suspension of ester 2 (1.5 g, 4.05 mmol) in
15.0 mL of MeOH : H2O was treated with 0.45 g (7.80 mmol) of KOH and
1.5 mL THF. The reaction mixture was stirred for 4 h at 60ꢀC, cooled to
room temperature and quenched with water (15.0 mL). The mixture was
extracted with ethyl acetate (2 ꢁ 15 mL) and the aqueous layer was acidified
to pH 2 with 1 N HCl and extracted with ethyl acetate (3 ꢁ 15 mL). The
combined organic phases were dried and evaporated. The residue was
recrystallized from ethyl acetate–hexane to give 0.95 g (87%) of acid 3,
m.p. 219–220ꢀC; IR (KBr): 3200–2500 (OH), 1690 and 1675 (C¼O), 1625
1
(C¼C) cmꢂ1; H NMR (CDCl3): ꢀ 3.82 (s, 3H, OCH3), 5.12 (s, 2H, CH2),
6.45 (d, 1H, J ¼ 15.9 Hz, CH), 7.05 (d, 1H, J ¼ 8.4 Hz, ArH), 6.95–7.15
(m, 2H), 7.20–7.50 (m, 10H, ArH), 7.66 (d, 1H, J ¼ 15.9 Hz, CH);
13C NMR (CDCl3); ꢀ 56.0, 70.9, 110.3, 113.5, 115.7, 122.2, 127.2, 127.7,
128.0, 128.3, 128.7, 136.2, 136.6, 145.1, 149.8, 150.4, 167.0. Anal. Calcd.
for C17H16O4: C, 71.82; H, 5.67. Found: C, 71.79; H, 5.56.
(4-Methylumbelliferone-7-yl) ferulate (5): To a stirred suspension of
1.09 g (4 mmol) of acid 3 in benzene (10 mL), 1.5 mL (20.6 mmol) of thionyl
chloride was added, and the mixture was heated under reflux for 40 min. The
solvent was removed under vaccum and the residue was redissolved in
toluene and evaporated again. The crude acid chloride 4 was dissolved in
toluene (10 mL) and added dropwise to an ice-cold strired solution of 7-
hydroxy-4-methylcoumarin (0.88 g, 5.0 mmol) in pyridine (10 mL). After 4 h,
the reaction mixture was evaporated to dryness. The solid was recrystallized
from ethanol to give 1.40 g (82%) of ester 5, m.p. 185–186ꢀC; IR (KBr):
1735 and 1725 (C¼O), 1630 (C¼C) cmꢂ1; 1H NMR (CDCl3): ꢀ 2.44 (d, 3H,
J ¼ 1.0 Hz, CH3), 3.94 (s, 3H, OCH3), 5.21 (s, 2H, CH2), 6.27 (d, 1H,
J ¼ 1.0 Hz, CH), 6.48 (d, 1H, J ¼ 15.9 Hz, CH), 6.91 (d, 1H, J ¼ 8.7 Hz,
ArH), 7.10–7.25 (m, 4H, ArH), 7.30–7.50 (m, 5H, ArH), 7.63 (d, 1H,
J ¼ 8.4 Hz, ArH), 7.83 (d, 1H, J ¼ 15.9 Hz, CH); 13C NMR (CDCl3): ꢀ
18.8, 56.1, 70.9, 110.4, 110.5, 113.3, 114.0, 114.4, 117.7, 118.3, 123.1,
125.4, 127.2, 127.3, 128.1, 128.3, 128.7, 136.4, 147.6, 149.8, 150.9, 152.1,
153.4, 154.2, 160.7, 165.0. Anal. Calcd. for C27H22O6: C, 73.29; H, 5.01.
Found: C, 73.10; H, 4.95.
(4-Methylumbelliferone-7-yl) dihydroferulate (6):
A solution of
(4-methylcoumarin-7-yl) ferulate 5 (150 mg, 0.34 mmol) in chloroform
(50 mL) was hydrogenated over 10% Pd/C (30 mg) under an H2 atmosphere
(2 atm) for 20 h, then the Pd/C was removed by filtration through Celite.
The filtrate was evaporated and the residue was crystallized from chloro-
form–ethyl acetate to give ester 6 (110 mg, 92%), m.p. 152–154ꢀC; IR (KBr):
3480 (OH), 1735 (C¼O), 1615 (C¼C) cmꢂ1
;
1H NMR (CDCl3): ꢀ 2.39

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4-METHYLUMBELLIFERYL DIHYDROFERULATE
3223
(d, 3H, J ¼ 1.0 Hz, CH3), 2.8–3.0 (m, 4H, CH2CH2), 3.85 (s, 3H, OCH3),
5.54 (s, 1H, OH), 6.70–6.80 (m, 2H, ArH), 6.90 (d, 1H, J ¼ 8.6 Hz, ArH),
6.95 (dd, 1H, J ¼ 2.2 and 8.6 Hz, ArH), 7.02 (d, 1H, J ¼ 2.2 Hz, ArH), 7.56
(d, 1H, J ¼ 8.6 Hz, ArH); 13C NMR [(CD3)2SO]: ꢀ 18.0, 29.7, 35.4, 55.4,
109.8, 112.3, 113.6, 115.2, 117.3, 118.2, 120.3, 126.2, 130.7, 144.8, 147.4,
152.7, 152.8, 153.4, 159.5, 170.8. Anal. Calcd. for C20H18O6: C, 67.79; H,
5.12. Found: C, 67.70; H, 5.00.
REFERENCES
1. Joseleau, J.P.; Comtat, J.; Ruel, K. Chemical Structure of Xylans and
their Interaction in the Plant Cell Walls. Prog. Biotechnol. 1992, 7, 1–15.
2. Biely, P. Microbial Xylanolytic Systems. Trends Biotechnol. 1985, 3,
286–290.
3. Williamson, G.; Kroon, P.A.; Faulds, C.B. Hairly Plant Polysacchar-
ides: A Close Shave with Microbial Esterases. Microbiol. 1998, 144,
2011–2023.
4. Fillingham, I.J.; Kroon, P.A.; Williamson, G.; Gilbert, H.J.;
Hazlewood, G.P. A Modular Cinnamoyl Ester Hydrolase from the
Anaerobic Fungus Piromyces equi Acts Synergistically with Xylanase
and is part of a Multiprotein Cellulose–Binding Cellulase–Hemicellulase
Complex. Biochem. J. 1999, 343, 215–224.
5. Hatfield, R.D.; Helm, R.F.; Ralph, J. Synthesis of methyl 5-O-Trans-
Feruloyl-a-L-Arabinofuranoside and its Use as a Substrate to Assess
Feruloyl Esterase Activity. Anal. Biochem. 1991, 194, 25–33.
6. Belletire, J.L.; Fry, D.F. Total synthesis of (ꢃ)-wikstromol. J. Org.
Chem. 1988, 53, 4724–4729.
7. DellaGreca, M.; Fiorentino, A.; Monaco, P.; Previtera, L.
Enantioselective Synthesis of Phenylpropanetriols. Synth. Commun.
1998, 28, 3693–3700.
8. Leschot, A.; Eyzaguirre, J. Unpublished results.
Received in the USA October 15, 2001

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