Preparation of saturated and unsaturated fatty acid hydrazides and long chain C-glycoside ketohydrazones

Article abstract of DOI:10.1039/c0gc00372g

A method is described to prepare both saturated and unsaturated fatty acid acyl hydrazides using a lipase as a catalyst. Hydrazides were generated from fatty acid methyl esters as well as directly from vegetable oils, and an organic co-solvent was not needed to maintain the integrity of the unsaturated fatty acids. Both C. antarctica lipase immobilized on acrylic resin and immobilized M. miehei lipase were used to catalyze the reaction, and they provided the desired acyl hydrazides with similar yields of 82.8% and 84.6%, respectively. Analysis of the products by MALDI-TOF-MS and GC-MS fragmentation pathways shows pure products free of starting methyl esters or triacylglycerols. These hydrazide molecules have been used, in conjunction with carbohydrate C-glycoside ketones, to prepare long chain C-glycoside ketohydrazones. This preparation does not require protecting groups or anomeric activation, and various C-glycoside ketohydrazones that retain the closed ring conformation of the parent sugars are described. These compounds have potential as renewable, sugar-based detergents in which the sugar moiety serves as the polar head group while the hydrazide alkyl chain is the non-polar component. The Royal Society of Chemistry 2010.

Full text of DOI:10.1039/c0gc00372g

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PAPER
www.rsc.org/greenchem | Green Chemistry
Preparation of saturated and unsaturated fatty acid hydrazides and long
chain C-glycoside ketohydrazones†
Chrissie A. Carpenter,a James A. Kenarb and Neil P. J. Price*a
Received 27th July 2010, Accepted 27th August 2010
DOI: 10.1039/c0gc00372g
A method is described to prepare both saturated and unsaturated fatty acid acyl hydrazides using
a lipase as a catalyst. Hydrazides were generated from fatty acid methyl esters as well as directly
from vegetable oils, and an organic co-solvent was not needed to maintain the integrity of the
unsaturated fatty acids. Both C. antarctica lipase immobilized on acrylic resin and immobilized
M. miehei lipase were used to catalyze the reaction, and they provided the desired acyl hydrazides
with similar yields of 82.8% and 84.6%, respectively. Analysis of the products by
MALDI-TOF-MS and GC-MS fragmentation pathways shows pure products free of starting
methyl esters or triacylglycerols. These hydrazide molecules have been used, in conjunction with
carbohydrate C-glycoside ketones, to prepare long chain C-glycoside ketohydrazones. This
preparation does not require protecting groups or anomeric activation, and various C-glycoside
ketohydrazones that retain the closed ring conformation of the parent sugars are described. These
compounds have potential as renewable, sugar-based detergents in which the sugar moiety serves
as the polar head group while the hydrazide alkyl chain is the non-polar component.
Triacylglycerols, or triglycerides, are a major class of naturally
occurring organic compounds comprising of approximately
90% fatty acids and 10% glycerol.1 They are produced in
considerable quantities in both vegetable and algal oils and
animal fats, making fatty acids a raw material with almost
unlimited potential.1
alcoholysis of vegetable oils using a hydrophobic solvent such
as petroleum ether,24,27 hexane,18,26 and cyclopentene.28 How-
ever, increasing interest has been focused on a reaction route
that does not include hydrophobic solvents such as the ones
listed above.16–17,19,21–23 Recently, fatty hydrazides were prepared
enzymatically, in a similar manner to transesterification, di-
rectly from palm oils.26 Synthesis was completed in a one-step
reaction catalyzed by Mucor miehei lipase using hexane as a
solvent.26
C-glycosides, derived from naturally occurring carbohydrates,
have potential for uses as natural product building blocks
and enzyme inhibitors.29,30 Because their anomeric center has
been transformed to a cyclic ether, C-glycosides are more
stable towards degradation. There are minimal conformational
differences between the O- or N-glycosides and the C-linked
analogues, and they possess similar structural flexibility and
pharmacological characteristics.29,30 As such, a growing interest
in this class of compounds has developed in recent years.
C-glycoside ketones have been prepared in aqueous alkaline
media via a Knoevenagel condensation of unprotected reducing
sugars with 2,4-pentanedione.31–35 Attempts have been made to
synthesize C-glycolipids by condensation of both symmetrical
and asymmetrical b-diketones with longer alkyl chain length.32
The target C-glycolipids were formed using longer reaction
times, although as a mixture of products in low to moderate
yields.32 In addition, insolubility of the more aliphatic b-
diketones in water required the use of an ethanol co-solvent.
Here we report that fatty acid hydrazides will react with
C-glycoside ketones to form aliphatic ketohydrazones in high
yields (Scheme 1).
Fatty acid hydrazides, which are N-acyl hydrazine derivatives,
are well established compounds first mentioned in the literature
in 1895.2,3 Unsubstituted hydrazide derivatives of fatty acids
were reported in the literature as early as 1914.4 More recently,
hydrazides have commonly been used to aid in spectroscopic
identification of fatty acids.5–8 In addition, their potential as
corrosion inhibitors9–11 and use for biomedical applications have
been explored.12–15
R
Immobilized Mucor miehei lipase (Lypozymeꢀ) and immobi-
R
lized Candida antarctica lipase B (Novozymeꢀ 435) have been
used to prepare biodiesel (mono-alkyl fatty acid esters) by trans-
esterification of vegetable oils using various types of short chain
alcohols,16–24 such as methanol, ethanol, or propanol.16–17,19,21–22,24
Pre-treatment of the lipase with butanol, prior to subjecting
it to reaction, has been shown to increase product yield.25
Hydrophobic solvents such as heptane, cyclohexane, and toluene
have been shown to preserve catalytic activity and increase
efficiency of enzymatic conversion.26 There are reports of
aRenewable Products Technology Research Unit, National Center for
Agricultural Utilization Research, Agricultural Research Service, United
States Department of Agriculture, 1815 North University Street, Peoria,
IL, USA. E-mail: Neil.Price@ars.usda.gov; Fax: +1 309 681 6040;
Tel: +1 309 681 6246
bFunctional Foods Research Unit, National Center for Agricultural
Utilization Research, Agricultural Research Service, United States
Department of Agriculture, 1815 North University Street, Peoria, IL,
USA
† Electronic supplementary information (ESI) available: Electron impact
mass spectrometry characterization. See DOI: 10.1039/c0gc00372g
This paper will describe the formation of acyl hydrazide
intermediates from both fatty acid esters and from plant
triacylglyceride oils. In addition, it describes the reaction of these
acyl hydrazides with C-glycoside ketones to generate a novel
family of C-glycoside ketohydrazones. These latter compounds
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Scheme 2 Reaction to form hydrazides from fatty acid methyl esters
from hydrazine hemisulfate salt.
Scheme 1 General reaction for ketohydrazones preparation.
Fatty acid hydrazides were prepared from commercially
available fatty acid methyl esters (FAMEs). This was first
attempted without lipase by reacting FAMEs with aqueous
hydrazine. While this route did produce the desired hydrazides,
the reaction temperature was high at 100 ◦C and yields were low
with less than 30% recovery. A more efficient and higher yielding
route employing milder reaction conditions was desirable.
Accordingly, we examined the use of two lipases, immobilized
Mucor miehei and immobilized Candida antarctica, to catalyze
the formation of hydrazides. Reaction of fatty acid methyl esters
such as methyl caprylate, methyl laurate, methyl palmitate, and
methyl oleate with hydrazine in the presence of C. antarctica
lipase as a catalyst at 40 ◦C in a water : 2-butanol : ethanol
(1 : 2 : 2) solvent mixture gave the corresponding hydrazides in
good yields after 24 h (Fig. 1). Water and ethanol were used for
solubility of the hydrazine and ester, while 2-butanol was chosen
for pre-treatment of immobilized C. antarctica lipase. The lipase
was recovered, rinsed with water, and saved for reactivation and
reuse at a later time.25
have considerable potential as a new class of “green” sugar-based
surfactants and detergents.
Results and discussion
Fatty acid hydrazides
Due to concerns about the safety, toxicity, and the costs
associated with shipping free hydrazine it was prepared in situ as
shown in Scheme 2. Hydrazine hemisulfate salt was dissolved in
water followed by addition of NaOH to give aqueous hydrazine
and sodium sulfate. Ethanol was added to the solution to
precipitate the unwanted sodium sulfate. The sodium sulfate
byproduct was removed by filtration to give free hydrazine
in an ethanol/water solution. A known amount of hydrazine
contained in the aqueous solution was then used in the synthesis
of fatty acid hydrazides from both fatty acid methyl esters as
well as directly from vegetable oils.
Fig. 1 MALDI-TOF-MS spectra showing characteristic [M]+ and [M + Na]+ peaks for acetone hydrazones prepared from (A) caprylic hydrazide
(m/z 198.5, m/z 220.5); (B) lauric hydrazide (m/z 254.6, m/z 276.6); (C) palmitic hydrazide (m/z 311.2, m/z 333.2); and (D) oleic hydrazide (m/z
337.2, m/z 359.2).
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Isolated fatty acid hydrazides from the lipase catalyzed reac-
tion gave yields ≥ 77%. Because the fatty acid methyl esters and
the fatty acid hydrazides have the same molecular weight, they
were also analyzed by MALDI-TOF-MS as the corresponding
acetone hydrazone and 3-heptanone hydrazone derivatives. This
derivatization ensured the compounds synthesized were the
target hydrazides, as ketones will not react with the fatty acid
methyl esters. The acetone and 3-heptanone hydrazones were
formed by adding the appropriate ketone to the fatty acid
hydrazide dissolved in methanol and agitating. This proved a
valuable tool in the structural determination of each of the
fatty acid hydrazides synthesized since they also proved suitable
for characterization by GC-MS based upon fragmentation
data from electron impact mass spectrometry (EI-MS). Fig. 1
shows the MALDI-TOF-MS data for the acetone hydrazone
derivatives.
yields, C. antarctica was chosen for further use because of cost
considerations.
In addition to hydrazides prepared from fatty acid methyl
esters, hydrazides have been prepared directly from vegetable
oils. Commercial vegetable oils (olive, sesame, and corn) were
used without modification. Due to the fatty acid composition
of the various oils, a mixture of fatty acid hydrazides were
prepared from one vegetable oil source, as shown in Scheme
3. It is important to note that the triacylglycerol R groups may
represent different acyl chains.
These combined methods clearly establish the synthesis of
the hydrazides from the starting methyl esters. As expected,
the lipase catalyzes the reaction quite effectively at a lower
temperature with increased yields. Furthermore, the lipase can
be regenerated in a relatively simple process and used for
additional reactions.25
Based on the success of the C. antarctica lipase to produce
hydrazides, a reaction was carried out with methyl laurate to
compare the lauric hydrazide yields produced by M. miehei
lipase relative to C. antarctica lipase. Reactions were carried
out in a side-by-side manner at 40 ◦C. Both lipases gave
isolated yields of lauric hydrazide >80% free of the starting
methyl ester. M. miehei gave a slightly better yield, 85%,
than C. antarctica, 83%. MALDI-TOF-MS analysis of the
acetone and 3-heptanone derivatives of each showed a clean
product free of the starting ester. Since both lipases gave similar
Scheme 3 General reaction to form acyl hydrazides from vegetable oil
triacylglycerides.
As with the acyl hydrazides derived from individual fatty
acid methyl esters, the hydrazides derived from vegetable oils
were converted to the corresponding acetone and 3-heptanone
derivatives. This derivatization facilitated analysis by MALDI-
TOF-MS and GC-MS. Fig. 2 shows the spectra obtained for the
acetone hydrazones derived from sesame oil, corn oil, and olive
oil. It is interesting to note that olive oil appears to contain
mostly saturated palmitic and stearic acid hydrazides while
sesame and corn oil have a greater amount of the unsaturated
oleic and linoleic acid hydrazides in accordance with the fatty
acid compositions of the starting vegetable oils. This implies
Fig. 2 MALDI-TOF-MS spectra for acetone hydrazones prepared from (A) sesame oil hydrazides, (B) corn oil hydrazides, and (C) olive oil
hydrazides showing characteristic [M + H]+ and [M + Na]+ peaks for palmitic hydrazone, m/z 311.1 and m/z 333.2; oleic hydrazone, m/z 337.2 and
m/z 359.2; linoleic hydrazone, m/z 335.1 and m/z 357.2; and stearic hydrazone, m/z 338.8 and m/z 361.2.
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dissolved in 1 : 1 MeOH/EtOH and heated to 50 ◦C for 4 h.
Table 1 m/z values for compounds of interest
Glucose-C-glycoside ketone was used in ~2-fold excess to ensure
complete reaction between the ketone and acyl hydrazide and to
eliminate free hydrazide remaining in solution. MALDI-TOF-
MS of the reaction products shows no acyl hydrazide starting
material, indicating complete conversion to the ketohydrazone.
The reaction was accomplished using hydrazides containing 8,
12, 16, and 18 carbon atoms.
Compound
[M + H]+ [M + Na]+
Starting C-glycoside ketones
Glucose-C-glycoside ketone
Xylose-C-glycoside ketone
Rhamnose-C-glycoside ketone
Galacturonic acid-C-glycoside ketone
Lactose-C-glycoside ketone
221
191
205
234
383
242
212
226
256
404
This method of ketohydrazone formation was not only
successfully implemented using hydrazides derived from indi-
vidual fatty acid methyl esters, but also with mixtures of fatty
acid hydrazides from vegetable oils. As vegetable oils produce
hydrazides of various chain lengths, a mixture of C-glycoside
ketohydrazones were formed as well. As can be seen from Fig.
3, the unique fatty acid profiles of the oils gave rise to different
glucose-C-glycoside ketohydrazones, including those with both
monounsaturated or polyunsaturated acyl chains. The double
bonds from the oil hydrazides are preserved due to the mild
nature of the reactions involved.
In addition to this method being generally applicable to a
variety of fatty acid hydrazides, from both methyl esters and veg-
etable oils, it can be used to create C-glycoside ketohydrazones
with different sugar head groups. Hence, C-glycoside ketones
can be synthesized with various starting sugars.33,35 General
applicability was demonstrated using a pentose, 6-deoxyhexose,
an acidic uronic acid, and a common disaccharide with lauric
hydrazide, as shown in Fig. 4. These carbohydrate-C-glycoside
ketones can be reacted in the manner described above to form
C-glycoside ketohydrazones.
Starting hydrazides
Caprylic hydrazide
Lauric hydrazide
Palmitic hydrazide
Stearic hydrazide
Oleic hydrazide
159
215
271
299
297
295
181
237
293
321
319
317
Linoleic hydrazide
Hydrazone products
Glucose-C-glycoside caprylic hydrazone
Glucose-C-glycoside lauric hydrazone
Glucose-C-glycoside palmitic hydrazone
Glucose-C-glycoside stearic hydrazone
Glucose-C-glycoside oleic hydrazone
Glucose-C-glycoside linoleic hydrazone
361
417
473
501
499
497
383
439
495
523
521
519
Xylose-C-glycoside lauric hydrazone
Rhamnose-C-glycoside lauric hydrazone
Galacturonic acid-C-glycoside lauric hydrazone 431
Lactose-C-glycoside lauric hydrazone
387
401
408
422
453
601
579
that the hydrazide components can be predicted and tailored to
particular compositions based on the fatty acid profile of the
starting vegetable oils.
It is important to note that not only saturated fatty acid
hydrazides were produced, but also monounsaturated and
polyunsaturated fatty acid hydrazides as well. Previous attempts
to synthesize unsaturated fatty acid hydrazides from hydrazine
and esters have been unsuccessful due to hydrogenation of the
double bond in the presence of hydrazine.15,36 In past literature,
the use of a hydrophobic co-solvent such as cyclopentene, to
protect the double bonds from hydrazine reduction, has been
employed to form unsaturated hydrazides with success.28 Unsat-
urated hydrazides can also be prepared by direct hydrazinolysis
in an atmosphere of nitrogen; results were confirmed by TLC
but no yields were reported.37
Experimental
Materials and general methods
Fatty acid methyl esters, hydrazine hemisulfate, sodium hydrox-
ide pellets, and carbohydrates were purchased from Sigma–
Aldrich. Immobilized C. antarctica lipase (lipase B, 10 000 U g-1)
expressed in Aspergilus niger and immobilized on acrylic resin,
and immobilized M. miehei lipase (>30 U g-1) were purchased
from Sigma–Aldrich. Olive oil, corn oil, and sesame oil were
purchased from a local grocery store.
MALDI-TOF mass spectra were recorded on a Bruker-
Daltonic Omniflex instrument operating in reflection mode. Ion
source 1 was set to 19.0 kV and source 2 was set to 14.0 kV with
lens and reflector voltages of 9.20 and 20.00 kV, respectively.
A 200-ns pulsed ion extraction was used. The instrument was
calibrated externally on a dp series of malto-oligosaccharides.
Samples (0.5 mL) were co-crystallized with the matrix (2,5-
dihydrobenzoic acid) onto a conventional 49-place stainless steel
target. Excitation was at 337.1 nm, typically at 80% of 150 mL
maximum output, and 60 shots were accumulated.
GC-MS analyses were performed on an Agilent 6860 N Series
gas chromatograph equipped with a 7683 Series autoinjector.
The GC was interfaced with an Agilent 5973 Series mass-
selective detector (MSD) configured in electron impact (EI)
mode. Chromatography was accomplished with a fused silica
capillary HP-1 column (30 m; 0.25 mm). Helium (18.6 ml
min-1) was used as the carrier gas. The oven temperature was
ramped over a linear gradient from 120 to 250 ◦C at 5 ◦C
Long chain C-glycoside ketohydrazones
Carbohydrate C-glycoside ketones were prepared using stan-
dard methods.31,33,35 With the use of an aqueous co-solvent,
the fatty acid hydrazides reacted with the C-glycoside ke-
tones quickly and under mild reaction conditions to produce
the corresponding C-glycoside ketohydrazones. The described
methodology affords the products cleanly without requiring
chromatographic clean-up, and is amenable to a variety of fatty
acid chain lengths and carbohydrate head groups.
Table 1 presents m/z values of glycoside ketone, acyl hy-
drazide, and ketohydrazone compounds expected to be present
in reaction mixtures as observed by MALDI-TOF-MS.
Glucose-C-glycoside ketone was used to prepare ketohydra-
zones from a variety of fatty acid hydrazides. The desired
hydrazide was added to an excess of glucose-C-glycoside ketone
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Fig. 3 MALDI-TOF-MS spectra for glucose-C-glycoside ketohydrazones prepared from (A) olive oil hydrazides, (B) sesame oil hydrazides, and
(C) corn oil hydrazides showing characteristic [M + Na]+ peaks for palmitic hydrazone (m/z 494.9), stearic hydrazone (m/z 522.9), oleic hydrazone
(m/z 520.9) and linoleic hydrazone (m/z 518.9).
Fig. 4 MALDI-TOF-MS spectra showing characteristic [M]+ and [M + Na]+ peaks for lauric ketohydrazones prepared from (A) xylose-C-glycoside
(m/z 386.7 and m/z 408.7), (B) rhamnose-C-glycoside (m/z 400.8 and m/z 422.8), (C) galacturonic acid-C-glycoside (m/z 431.3 and m/z 453.2), and
(D) lactose-C-glycoside (m/z 579.0 and m/z 601.0). Galacturonic acid-C-glycoside hydrazone also has a sodium salt peak assigned as [M + Na2]+ at
475.2 m/z.
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min-1. Injector and detector/interface temperatures were 275
and 300 ◦C, respectively. Mass spectra were recorded in positive
ion mode over the range m/z 45–550.
filtration. To a suspension of M. miehei lipase (0.209 g) in
2-butanol (3.0 mL) was added the hydrazine solution and
methyl laurate (0.393 mL, 1.60 mmol). The suspension was
heated (40 ◦C) for 24 h, cooled, and the lipase removed by
vacuum filtration. The resulting filtrate was dried under vacuum
overnight to give lauric hydrazide (0.289 g, 1.35 mmol, 85%
yield) as an off-white solid. MALDI-TOF-MS analysis of the
acetone and 3-heptanone hydrazone derivatives showed pure
lauric hydrazide with no trace of unreacted methyl ester. GC-
MS analysis further confirmed product identification.
General procedure to form acyl hydrazides from methyl esters
(no lipase). Hydrazine hemisulfate (0.801 g, 9.87 mmol) was
dissolved in water (8 mL) and cooled in an ice bath. Sodium
hydroxide pellets (0.401 g, 10.0 mmol) were added to the
solution and stirred until completely dissolved. Ethanol (8 mL)
was added to precipitate sodium sulfate impurities which were
removed by vacuum filtration. To the resulting filtrate, methyl
caprylate (445 mL, 2.47 mmol) was added and the mixture
was heated (100 ◦C) for 2 h. The reaction was cooled and
concentrated under reduced pressure to give caprylic hydrazide
(0.082 g, 0.520 mmol, 20.6% yield) as a white solid. The product
was identified by MALDI-TOF-MS and GC-MS analysis of the
acetone and 3-heptanone hydrazone derivatives.
General procedure to acyl form hydrazides from vegetable oils.
Sesame oil (2.033 g) and C. antarctica lipase (1.038 g) were
weighed out into an Erlenmeyer flask. Ethanol (3.0 mL) was
then added to make a slurry which was placed on an orbital
shaker at 200 rpm and 28 ◦C for 24 h.
Prior to removing the lipase slurry from the orbital shaker,
hydrazine hemisulfate (2.799 g, 34.5 mmol) was dissolved in
water (20 mL) and cooled in an ice bath. To the cool solution,
sodium hydroxide pellets (1.384 g, 34.6 mmol) were added and
the mixture stirred to completely dissolve the pellets. Ethanol
(30 mL) was added to precipitate sodium salt impurities which
were removed by vacuum filtration. The hydrazine filtrate was
retained.
The lipase/sesame oil slurry was filtered through a BD 5 mL
leur-lock syringe with a Millex-SR 0.5 mm filter syringe and
added directly into the hydrazine salt solution. A fine precipitate
formed almost immediately. The mixture was placed on an
orbital shaker at 200 rpm and 35 ◦C for 72 h. The solution was
cooled to approximately 10 ◦C and the precipitate was filtered,
collected, and dried under vacuum overnight to give a soapy
lightly yellow solid. The acetone and 3-heptanone hydrazone
derivatives were prepared and analyzed by MALDI-TOF-MS.
General procedure to form acyl hydrazides from methyl es-
ters (C. antarctica lipase). Hydrazine hemisulfate (0.186 g,
2.29 mmol) was dissolved in water (1.0 mL) and cooled in an ice
bath. Sodium hydroxide pellets (0.091 g, 2.28 mmol) were added
to the solution and stirred until completely dissolved. Ethanol
(3.0 mL) was added to precipitate the sodium sulfate impurities
which were subsequently removed by vacuum filtration. To
a suspension of C. antarctica lipase (0.115 g) in 2-butanol
(2.0 mL) was added the hydrazine solution and methyl caprylate
(0.164 mL, 0.910 mmol). The suspension was heated (40 ◦C)
for 24 h, cooled, and lipase removed by vacuum filtration.
The resulting filtrate was concentrated and dried under vacuum
overnight to give caprylic hydrazide (0.111 g, 0.704 mmol, 77.4%
yield) as an off-white solid. MALDI-TOF-MS analysis of the
acetone and 3-heptanone hydrazone derivatives showed pure
caprylic hydrazide with no trace of unreacted methyl ester. GC-
MS analysis further confirmed product identification.
General procedure for the C-glycoside ketone formation. D-
glucose (0.073 g, 0.408 mmol) was dissolved in sodium bicar-
bonate buffer (2 mL). 2,4-Pentanedione (750 mL, 7.30 mmol)
was added and the reaction was heated at 80 ◦C (4 h) with
occasional vortexing. The solution was allowed to cool to room
temperature and extracted with EtOAc (2 ¥ 2 mL); the organic
layer was removed. To the aqueous layer, Dowex-50W H+-form
strong cation exchange resin (ca. 50 mg) was added and agitated
by hand. The resin was removed by filtration and the filtrate was
analyzed by MALDI-TOF-MS.
Commercial lipase comparison experiments
Lauric hydrazide (immobilized C. antarctica lipase). Hy-
drazine hemisulfate (0.373 g, 4.60 mmol) was dissolved in water
(1.5 mL) and cooled in an ice bath. Sodium hydroxide pellets
(0.184 g, 4.61 mmol) were added to the solution and stirred
until completely dissolved. Ethanol (3.0 mL) was added to
precipitate the sodium salt impurities, which were removed by
vacuum filtration. To a suspension of C. antarctica lipase (0.201
g) in 2-butanol (3.0 mL) was added the hydrazine solution and
methyl laurate (0.378 mL, 1.53 mmol). The suspension was
heated (40 ◦C) for 24 h, cooled, and lipase removed by vacuum
filtration. The resulting filtrate was concentrated and dried under
vacuum overnight to give lauric hydrazide (0.272 g, 1.27 mmol,
83% yield) as an off-white solid. MALDI-TOF-MS analysis of
the acetone and 3-heptanone hydrazone derivatives showed pure
lauric hydrazide with no trace of unreacted methyl ester. GC-MS
analysis further confirmed product identification.
General procedure for the C-glycoside hydrazone formation.
Lauric hydrazide (0.029 g, 0.137 mmol) was added to dried
glucose-C-glycoside ketone (0.063 g, 0.269 mmol). The mixture
was dissolved in 2 mL 1 : 1 MeOH/EtOH with vortexing
and heat to 50 ◦C for 4 h. After cooling, the samples were
concentrated to dryness and analyzed by MALDI-TOF-MS.
Conclusions
Lauric hydrazide (immobilized M. miehei lipase). Hydrazine
hemisulfate (0.388 g, 4.78 mmol) was dissolved in water (1.5 mL)
and cooled in an ice bath. Sodium hydroxide pellets (0.192 g,
4.79 mmol) were added to the solution and stirred until
completely dissolved. Ethanol (3.0 mL) was added to precipitate
the sodium salt impurities, which were removed by vacuum
In conclusion, we have prepared fatty acid hydrazides from
commercially available methyl esters and commercially available
vegetable oils using lipase to catalyze the reaction. The methyl
esters used varied from 8 to 18 carbons and were both saturated
and monounsaturated. General applicability of this method
to vegetable oils was demonstrated with extra-virgin olive oil,
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sesame oil, and corn oil. The hydrazine hemisulfate salt was
used to prepare hydrazine in situ and provides a less expensive
and toxic alternative to aqueous hydrazine. No organic solvents
were needed in the vegetable oil reactions, as in previous
reports.18,24,26–28 Moreover, mono- and polyunsaturated fatty acid
hydrazides were prepared successfully. In addition, a general
and green method has been developed to produce hydrazones
of carbohydrate-C-glycoside ketones using the prepared fatty
acid hydrazides. Both the carbohydrate and the aliphatic, fatty
acid portion can be manipulated to create a wide variety of
molecules. No activation of the anomeric center is needed, and
protection and deprotection of the carbohydrate is unnecessary.
The reaction is carried out in aqueous buffer and the integrity
of the closed-ring parent sugar is maintained. The nature of
the acyl hydrazones gives these molecules potential for use as
biodegradable, plant-derived surfactants. Further investigation
is ongoing.
9 M. A. Quraishi, R. Sardar and D. Jamal, Mater. Chem. Phys., 2001,
71, 309.
10 S. D. Toliwal, Indian J. Chem. Technol., 2009, 16, 32.
11 S. D. Toliwal, J. Sci. Ind. Res. India, 2009, 68, 235.
12 M. R. Banday and A. Rauf, Chin. Chem. Lett., 2008, 19, 1427.
13 K. Effenberger, S. Breyer and R. Schobert, Eur. J. Med. Chem., 2010,
45, 1947.
14 M. R. Banday, Indian J. Chem. B, 2009, 48, 97.
15 A. Rauf, M. R. Banday and R. H. Mattoo, Acta Chim. Slov., 2008,
55, 448.
16 R. C. Rodrigues, G. Volpato, K. Wada and A. Z. Ayub, J. Am. Oil
Chem. Soc., 2008, 85, 925.
17 J.-F. Shaw and D.-L. Wang, Enzyme Microb. Technol., 1991, 13, 544.
18 L. A. Nelson, T. A. Foglia and W. N. Marmer, J. Am. Oil Chem. Soc.,
1996, 73, 1191.
19 Y. Watanabe, Y. Shimada, A. Sugihara, H. Noda, H. Fukuda and Y.
Tominaga, J. Am. Oil Chem. Soc., 2000, 77, 355.
20 S. P. Singh and D. Singh, Renewable Sustainable Energy Rev., 2010,
14, 200.
21 B. Selmi and D. Thomas, J. Am. Oil Chem. Soc., 1998, 75, 691.
22 E. Herna´ndez-Mart´ın and C. Otero, Bioresour. Technol., 2008, 99,
277.
23 Y.-Y. Linko, M. La¨msa¨, X. Wu, E. Uosukainen, J. Seppa¨la¨ and P.
Linko, J. Biotechnol., 1998, 66, 41.
24 M. Mittelbach, J. Am. Oil Chem. Soc., 1990, 67, 168.
25 J.-W. Chen and W.-T. Wu, J. Biosci. Bioeng., 2003, 95, 466.
26 S. Mohamad, W. M. Z. W. Yunus, M. J. Haron and M. Z. A. Rahman,
J. Oleo. Sci., 2008, 57, 263.
27 L. Deng, T. Tan, F. Wang and X. Xu, Eur. J. Lipid Sci. Technol., 2003,
105, 727.
28 V. P. Agrawal, J. Lipid Res., 1983, 24, 216.
29 D. E. Levy and C. Tang, The Chemistry of C-Glycosides, Pergamon,
New York, 1995.
30 M. H. D. Postema, Tetrahedron, 1992, 48, 8545.
31 F. Rodrigues, Y. Canac and A. Lubineau, Chem. Commun., 2000,
2049.
32 Y. Hersant, R. Abou-Jneid, Y. Canac, A. Lubineau, M. Philippe, D.
Semeria, X. Radisson and M. Scherrmann, Carbohydr. Res., 2004,
339, 741.
Acknowledgements
The authors declare no competing financial interests. We would
like to thank Trina Hartman for technical assistance. Mention
of trade names or commercial products in this article is solely
for the purpose of providing specific information and does not
imply recommendation or endorsement by the U.S. Department
of Agriculture.
References
1 H. J. Harwood, Prog. Chem. Fats Other Lipids, 1952, 1, 127.
2 E. Licandro and D. Perdicchia, Eur. J. Org. Chem., 2004, 665.
3 G. Scho¨fer and N. Schwan, J Prakt Chem, 1895, 51, 180.
4 T. Curtius, J. Prakt. Chem., 1914, 89, 481.
33 I. Riemann, M. Papadopoulos, M. Knorst and W. Fessner, Aust. J.
Chem., 2002, 55, 147.
34 N. Bragnier and M.-C. Scherrmann, Synthesis, 2005, 5, 814.
35 N. P. J. Price, F. A. Momany and A. Adeuya, J. Mass Spectrom.,
2007, 43, 53.
36 L. Kyame, G. S. Fisher and W. G. Bickford, J. Am. Oil Chem. Soc.,
1947, 24, 332.
5 H. Miwa, C. Hiyama and M. Yamamoto, J. Chromatogr., A, 1985,
321, 165.
6 V. P. Agrawal and E. Schulte, Anal. Biochem., 1983, 131, 356.
7 H. Zhang, X.-j. Li, D. B. Martin and R. Aebersold, Nat. Biotechnol.,
2003, 21, 660.
37 G. M. Kinhikar, B. Y. Rao and C. V. N. Rao, Fett. Wiss. Technol.,
1970, 72, 165.
8 A. Ruiz-Rodriguez, G. Reglero and E. Iban˜ez, J. Pharm. Biomed.
Anal., 2010, 51, 305.
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