Name : Yulia
Nim
: RSA1C110015
1.1. Explain
the triterpenoid biosynthetic
pathway, identify important factors
that determine the quantities produced many triterpenoids.
Answer
:
Triterpenoid
carbon skeleton is
a compound derived from six
isoprene units and
the biosynthesis derived
from C30 acyclic
hydrocarbons, ie skualena.
Biosynthesis
of triterpenoid :
Biosynthesis
tritepenoid starting from compound squalene derived from mevalonic biosynthetic
pathways whereby acetic acid is activated by coenzyme A that will menghasilkkan
IPP and IPP is synthesized to form squalene, and squalene with the assistance
of the NADH + H + and NADH + + H2O will produce compound 2.3 2.3 epoxy compound
hydrosqualene then underwent cyclization and elimination of the double bond so
that the positively charged carbon atom, then these compounds will undergo
further cyclization and double bonds undergo elimination to form a new hydrogen
bond. Triterpenoid compounds forming.
Factors that
play an important role in the biosynthesis of these compounds is sequalene and
H2O. Where sequalene compounds derived from active isoprene formation from
acetic acid via mevalonic acid. And the existence of groups formed hydrogen
bond cyclization.
2.
Describe
the structure determination of flavonoids, specificity and intensity of absorption signal by using IR
and NMR spectra.
Give the example
of at least two different structures.
Answer
:
Infrared
spectroscopy is very useful for qualitative analysis (identification) of
organic compounds due to the unique spectrum generated by any organic substance
with structural peaks corresponding to different features. a carbonyl group, C
= O, always absorb infrared light at 1670-1780 cm-1, which causes the carbonyl
bond to stretch. a carbonyl group, C = O, always absorb infrared light at
1670-1780 cm-1, which causes the carbonyl bond to stretch. Cluster C = O
present in the region 1820 - 1600 cm-1 (5.6 to 6.1 m). The peak is usually the
strongest in the spectrum width mediun. Absorption is very characteristic. C =
C has a weak absorption near 1650 cm-1 (6.1 m) high medium strong uptake in the
region 1650-1450 cm-1 (6.7 m). Often indicate the presence of aromatic rings.
if a compound spectrum of compound X showed absorption bands at number
gelombang1455 cm-1. it can be concluded that the group-containing compound X
cyclo pentane. The frequency is absorbed depends on the functional groups in
molecules and molecular symmetry. IR radiation can only be absorbed by the bonds
in a molecule, if the radiation has the right energy to cause vibrations of the
bonds. disruption of the functional groups of contaminants will interfere with
the signal curve obtained infrared spectra contain many absorption associated
with the systems that interact in molecular vibrations and therefore has a
unique characteristic for each molecule then the spectrum gives absorption
bands are characteristic as well. Stretching absorptions usually produce
stronger peaks than bending, but weakened strethcing uptake may be useful in
distinguishing the same type of bond (eg aromatic substitution). IR spectra of
hydroxyl-containing compounds without seeing this broad signal. broad peak of
OH was replaced by a sharp signal around 3600 cm-1.
NMR
spectrum which has a specific absorption systems under the influence of a
magnetic field and it is not on UV-VIS and IR, the energy of electromagnetic
radiation in the radio frequency region. higher sensitivity of NMR spectroscopy
with increasing magnetic field strength. magnetic field homogeneity would
produce wide ribbons and signal distortion. The greater the NMR spectrometer,
the separation between the resonance peaks in the NMR spectrum the greater
number of signals in the NMR spectrum showed the number of nuclei with
different chemical environment of the molecules analyzed. Core protected
effects of high (more shielded core), the core will resonate at high magnetic
field strength so as to have the slide chemistry (δ) is lower than the standard
compound. Notch signaling NMR spectrum will help explain to us the type of
protons in a molecule, whether aromatic, aliphatic, primary, secondary,
tertiary, benzyl, vinyl, asitilen, adjacent to halogen or other groups.
Spectrum
IR of antochianin
-OH group is at 3700-3100
cm -1 absorption band with a strong signal. Then the group C = O absorption is in the
region 2100 cm-1 with a small enough signal.
Then the group C
= C absorption
is shown by region 1600 cm-1 with the signal being. And group
C-O is the
absorption region 1080-1300 cm -1 with
a small signal
absorption.
Spectrum
NMR of antochianin
At
resonance 6-7 minutes with a very strong signal and shows a very high retention
Similarly, the resonance
was also detected
OH group. Similarly, the resonance region
9-10 minutes have
strong signal and high retention.
Spectrum
IR of quercetin
-OH
group is in the region of wavelength absorption 3500-3389 cm-1 with
a very strong signal. Cluster C = C are in the catchment area with a wavelength of 1615-1614 cm -1. In the catchment area 1513 cm
-1 indicates the presence of C = C aromatic group. And
the absorption band 1243-1091 cm -1 indicate
the presence of CO groups.
And a catchment area with a wavelength of 807-675cm -1 indicates a
CH group.
Spectrum
NMR of quercetin
At
resonance 6 minutes in retention 0,2
later in the resonance region is at 10 minutes
retention 0,4. Furthermore,
the retention of 1.4
with a signal that is at the resonance region 12
minutes. And on 20 minutes
resonance with a strong signal indicating retention of 2,2.
3.
In the isolation of alkaloids,
in the early stages of acid or base
required conditions. Explain the basis of
the use of reagents, and give examples of at
least three kinds of alkaloids.
Answer
:
Since
alkaloids are organic compounds containing alkali similar
to an alkaline nitrogen atom in the heterocyclic
ring. Because it is alkaline, plants containing
alkaloids serve as
a base mineral to maintain
ion balance.
For
example, the isolation of caffeine use
acid-base extraction is a type of extraction that is based on the properties
of acids and bases organic
compounds.
Solid liquid extraction performed an intensive process of separating caffeine from the solution. In the early stages, leaf C brewed with boiling water. This is intended to increase the solubility of caffeine in water. In this case, the temperature increase means adding heat increases the kinetic energy mix so that more easily occur dissolution. With this, it is hoped, the caffeine is extracted to achieve the optimum amount. That is the basic use of acid or alkaline reagents.
Solid liquid extraction performed an intensive process of separating caffeine from the solution. In the early stages, leaf C brewed with boiling water. This is intended to increase the solubility of caffeine in water. In this case, the temperature increase means adding heat increases the kinetic energy mix so that more easily occur dissolution. With this, it is hoped, the caffeine is extracted to achieve the optimum amount. That is the basic use of acid or alkaline reagents.
Tannins
are phenolic compounds that have an OH group on
the aromatic ring and is quite sour. Tannin
can dissolve in
water and also in dichloromethane.
Because we want to extract the pure caffeine,
tannin must be removed from the organic phase of
this solution. In this case, we
must make the tannins
soluble in water and
insoluble in dichloromethane dissolving
more caffeine than
water. The trick is
to change the acidic tannins
into salt (deprotonisasi-OH) that turned into a
phenolic anion is
not soluble in dichloromethane, but
insoluble in water.
Examples of
alkaloid compounds
1. Nicotine is one of the most widely
known alkaloids. This compound is an alkaloid compound with the simplest form
of structure. However, the effect of its use is not as simple a form structure.
As we have seen, that nicotine is the active substances contained in cigarettes
and have properties quite dangerous. Nicotine will have toxic properties
(poison) that are harmful if used in high enough dosis.
The isolation is :
a. 25 grams of chopped dried tobacco
leaves wrapped in filter paper that has been put into the Soxhlet apparatus,
extraction using 300 ml of methanol for 7 jam.sampel used is 100 grams so the
extraction is done 4 times.
b. Extract / fltrat resulting solution
is evaporated until the resulting filtrate concentrated or only 10% of the
original volume.
c. Pour into a concentrated solution in
the erlenmeyer flask and acidified with 2 M H2SO4 at 25 ml. The solution was
stirred with a magnetic stirer to be homogeneous. The solution was tested with
litmus paper to red. Then extracted with a chloroform solution of 25 ml 3 times
a separating funnel.
d. The resulting extracts were tested
with the bottom layer of reagent dragendrof, if there is a positive alkaloid
orange precipitate.
e. The extract was neutralized again
with NH4OH and then extracted again with chloroform 3 times.
f. The extract obtained was evaporated
to aerate, then purified by column chromatography with silica gel as the
stationary phase 11.5 g, column length 10 cm, 3 cm diameter column and eluent
n-hexane and chloroform, methanol with a ratio of 1:0, 7: 3, 5:5, 3:7 and 0:1
respectively 10 ml.
g. The results of column chromatography
followed by TLC with a developing solution of methanol.
h. Extract then tested by using GC-MS,
UV-Vis spectrophotometer, and IR spectrophotometers.
2. Morphine is an alkaloid first
isolated and purified from the wild. This compound is one of the alkaloids
which belong to the class of drugs. This compound was isolated from opium sap
and seeds, so that dependence on morphine is often referred to as addiction.
The isolation is :
3. Caffeine is an alkaloid similar
compounds belonged metilxanthine (1,3,7-trimethylxantine). Psychological
effects produced can be varied and can lead to dependence. Caffeine is pretty
much contained in the (30-75 mg / cup), while leaf tea also contains tannins
and a small amount of chlorophyll. The structure of caffeine wake of purine
ring system, which is biologically important and many of them are found in
nucleic acids.
The isolation is :
Mass of
three tea bags of Red Rose tea was obtained using the electronic scale. 200 g
of distilled water was heated to 99 oC in a beaker using the hot
plate. The bags were placed into the beaker and swirled for 60 seconds, at
which time the three bags were removed and the liquid remaining in the bags
squeezed back into the beaker using the two glass slides. The beaker was placed
into the cold water bath in the large plastic container. When the temperature
had reached 26 oC, the tea was strained using filter paper.
120 ml 6M
NaOH was prepared by dissolving 28.7 g of solid NaOH into 120 ml of distilled
water. This was set aside. The contents of the tea beaker were placed into the
separatory funnel and allowed to settle. 20 mL of CHCl3 was added
and the funnel was inverted back and forth ten times, stopping every three
times to allow gas to escape. The organic layer in the funnel was released into
a new beaker. The 20 mL CHCl3 washing was repeated twice more, each
time releasing the organic layer into the second beaker. After the three
washings, the contents of the separatory funnel were discarded and the contents
of the second beaker were placed into the separatory funnel. Two washings with
20 mL NaOH were done, followed by one washing with 20 mL of distilled water.
Next, the
contents of the separatory funnel were poured into the third beaker. This was
placed over the hot plate and the temperature was set to "6". When
all the liquid had evaporated, the beaker was massed on the electronic scale.
Then, the white residue was scraped off the bottom of the beaker and onto a
massed piece of paper. Both the clean beaker and the piece of paper with the
white residue were massed. In this way, the mass of the residue was obtained in
two separate ways.
4. Describe
the relationship between biosynthesis, methods of isolation and structural
determination of compounds of
natural ingredients. Give an example.
Answer
:
Association
is
if we see of
understanding biosynthesis pathway is a sequence or a process in which consists
of the stages of the formation of simple compounds into complex compounds.
Where if you want to isolate a compound, we must know that we will compound
insulation first. To obtain compounds isolated complex for our needs
biosynthetic pathway, which we need in this biosynthetic enzymes and precursors
in the formation of such compounds, after we obtain the complex compounds that
we want, we can isolate the new compound to get a really pure mixture of other
compounds or to obtain the desired pure isolates. Because the compounds derived
from biosynthesis surely still mixed with other compounds that are not pure
compounds. Further identification of the structure of a compound. To identify
such compounds is necessary in order to yield pure compound identification of
compounds obtained really large uptake purified compounds. Pure compound was
obtained from the isolated and then purified. With the determination of this
structure we can determine the absorbance and wavelength of each functional
group of pure compounds which we derive from the isolation.
For example
in the biosynthesis, isolation and structural determination of cholesterol.
Biosynthesis of Cholesterol
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1. Synthesis of Mevalonate from Acetate
The first stage in cholesterol biosynthesis leads to
the intermediate mevalonate. Two molecules of acetyl-CoA condense,
forming acetoacetyl-CoA, which condenses with a third molecule of acetyl-CoA
to yield the six-carbon compound β-hydroxy-β-methylglutaryl-CoA (HMG-CoA).
These first two reactions, catalyzed by thiolase and HMG-CoA synthase,
respectively, are reversible and do not commit the cell to the synthesis of
cholesterol or other isoprenoid compounds.
The third reaction is the committed step: the
reduction of HMGCoA to mevalonate, for which two molecules of NADPH each
donate two electrons. HMG-CoA reductase, an integral membrane protein
of the smooth endoplasmic reticulum, is the major point of regulation on the
pathway to cholesterol, as we shall see.
2. ConUersion of MeUalonate to Two Activated
Isoprenes
In the next stage of cholesterol synthesis, three
phosphate groups are transferred from three ATP molecules to mevalonate. The
phosphate attached to the C-3 hydroxyl group of mevalonate in the
intermediate 3-phospho-5-pyrophosphomevalonate is a good leaving group; in
the next step this phosphate and the nearby carboxyl group both leave,
producing a double bond in the five-carbon product, Δ3-isopentenyl
pyrophosphate. This is the first of the two activated isoprenes central
to cholesterol formation. Isomerization of Δ3-isopentenyl
pyrophosphate yields the second activated isoprene, dimethylallyl
pyrophosphate.
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3. Condensation of Six ActiUated Isoprene Units to
Form Squalene
Isopentenyl pyrophosphate and dimethylallyl
pyrophosphate now undergo a "head-to-tail" condensation in which one
pyrophosphate group is displaced and a 10-carbon chain, geranyl
pyrophosphate, is formed. (The "head" is the end to which
pyrophosphate is joined.) Geranyl pyrophosphate undergoes another head-to-tail
condensation with isopentenyl pyrophosphate, yielding the 15-carbon
intermediate farnesyl pyrophosphate. Finally, two molecules of farnesyl
pyrophosphate join head to head, with the elimination of both pyrophosphate
groups, forming squalene. The common names of these compounds derive
from the sources from which they were first isolated. Geraniol, a component of
rose oil, has the smell of geraniums, and farnesol is a scent found in the
flowers of a tree, Farnese acacia. Many natural scents of plant origin are
synthesized from isoprene units. Squalene, first isolated from the liver of
sharks (genus Squalus), has 30 carbons, 24 in the main chain and 6 in the form
of methyl group branches.
4.Conversion of Squalene to the Four-Iling Steroid
Nucleus
When the squalene molecule is represented, the
relationship of its linear structure to the cyclic structure of the sterols is
apparent. All of the sterols have four fused rings (the steroid nucleus) and
all are alcohols, with a hydroxyl group at C-3; thus the name
"sterol." The action of squalene monooxygenase adds one oxygen
atom from O2 to the end of the squalene chain, forming an epoxide.
This enzyme is another mixed-function oxidase (Box 20-1); NADPH reduces the
other oxygen atom of O2 to H2O. The double bonds of the
product, squalene2,3-epoxide, are positioned so that a remarkable
concerted reaction can convert the linear squalene epoxide into a cyclic
structure. In animal cells, this cyclization results in the formation of lanosterol,
which contains the four rings characteristic of the steroid nucleus. Lanosterol
is finally converted into cholesterol in a series of about 20 reactions,
including the migration of some methyl groups and the removal of others. Elucidation
of this extraordinary biosynthetic pathway, one of the most complex known, was
accomplished by Konrad Bloch, Feodor Lynen, John Cornforth, and George Popjak
in the late 1950s.
Cholesterol is the sterol characteristic of animal
cells, but plants, fungi, and protists make other, closely related sterols
instead of cholesterol, using the same synthetic pathway as far as
squalene-2,3-epoxide. At this point the synthetic pathways diverge slightly,
yielding other sterols: stigmasterol in many plants and ergosterol in fungi,
for example.
Isolation
and Purification of Cholesterol from Egg Yolk
Two hard boiled egg yolks were twice extracted with diethyl ether and methanol, with the filtrate collected via vacuum filtration. Potassium hydroxide pellets were added to the filtrate, the ether was distilled off, and the mixture was saponified by reflux. The crude cholesterol was isolated through a series of ether extractions and aqueous washes; then the ether was dried with MgSO4 and removed by rotary evaporation. The melting point of the yellow, sticky crude product was 91-119 oC. This crude product was then recrystallized from methanol, yielding 0.128g of pale yellow crystals with a melting point of 131-135 oC. This represents 0.33% of the original mass of the two yolks. The cholesterol was then dissolved in ether and further purified by bromination with a bromine/acetic acid reagent and debromination with zinc powder, a series of aqueous washes, and a final recrystallization from methanol. Here, a yield of 28% was recovered from an initial mass of 100 mg of recrystallized material. The melting point of the off-white crystalline final product was 146-148 oC, which is very close to the literature value for cholesterol of 148.5 oC.
From both the melting points and the physical appearances, it is apparent that the final bromination/debromination procedure did in fact further purify the product. The percent of cholesterol in egg yolks was calculated using the mass of the recrystallized product. This calculation does not seem to be valid, as the melting points demonstrated that the recrystallized product was not as pure as the final product. The goal of the experiment was accomplished; cholesterol was isolated and purified from the egg yolks.
Cholesterol
identification with IR spectrum
Through the
identification of the IR spectrum of this we
can know that the catchment area with a wavelength of 4,000 to 2,500, known
as the absorption peak group NH, CH and OH single bond. In the catchment
area range 2,500 to 2,000, a triple bond absorption
peak. the catchment area is the range of 2000
to 1500 as the
absorption peak of the double bond C = O, C = N and C = C.
