Chemistry of Natural Products Test

Chemistry of Natural Products

Name                       :  Lina Purwanti

Student number        :  RSA1C110009

Study Program         :  Chemistry Education of ISSTE

     1. Jelaskan dalam jalur biosintesis triterpenoid, identifikasilah faktor-faktor penting yang sangat menentukan  dihasilkannya triterpenoid dalam kuantitas yang banyak. 

Answer :

Triterpenoid carbon skeleton is a compound derived from six isoprene units and the biosynthesis derived from C30 acyclic hydrocarbons, ie skualena.

SYNTHESIS TERPENOID

Terpenoids is a form of the compound with large structures in natural product-derived and isoprene unit (C5) are coupled in the model head to tail, whereas isoprene units derived from acetic acid metabolism by mevalonic acid pathway (MVA). The reaaksinya are as follows:

Figure 1 Line Acetate is the formation of IPP formation of terpenoids Via Bricks mevalonic acid (http://nadjeeb.wordpress.com).

In general, the biosynthesis of terpenoids with the three basic reactions, namely:

1. Formation of active isoprene derived from acetic acid via mevalonic acid.

2. Merging head and tail of two isoprene units to form mono-, seskui-, di-. Sester-,      and poly-terpenoids.

3. The incorporation of the tail and the tail unit C-15 or C-20 produces triterpenoids and steroids.

The mechanism of the reaction steps of terpenoid biosynthesis is activated by acetic acid as coenzyme A did produce acid Claisen type condensation asetoasetat.

Compounds produced by the condensation of acetyl coenzyme A did produce aldol type branched carbon chains as found in mevalinat acid, subsequent reactions are fosforialsi, elimination of phosphoric acid and dekarboksilasi produce isopentenyl (IPP) who later became dimethyl allyl berisomerisasi piropospat (DMAPP) by the enzyme isomeriasi. IPP as active isoprene unti joined head to tail with DMAPP and this merger is the first step of the polymerization of isoprene to produce terpenoids.

This merger occurs because electrons attack the double bond carbon atoms of IPP to DMAPP electron deficient followed by the removal of ions that produce geranil. pirofosfat pyrophosphate (GPP) is an intermediate for all monoterpenoid compounds. Merger between one unti further IPP and GPP with the same result menaisme Farnesil pyrophosphate (FPP), which is an intermediate for all compounds seskuiterpenoid. Diterpenoid compounds derived from geranil-geranil Pyrophosphate (GGPP) derived from the condensation between one unti IPP ​​and GPP by the same mechanism. The mechanism of biosynthesis of terpenoid compounds are as follows:

         From that picture in biosynthesis we can get if there is enzyme such as isomeriasi enzyme to help reaction faster, Co-A to make active acetic acid so will happen condensation, H₂O, and acetic acid 

2.   Jelaskan dalam penentuan struktur flavonoid, kekhasan signal dan intensitas serapan dengan menggunakan spektrum IR dan NMR. Berikan dengan contoh sekurang-kurangnya dua struktur yang berbeda.  

Answer :

IR Spectroscopy  : This section takes you through typical IR spectra of compounds with different functional groups to help you recognize distinctive, characteristic IR bands. The final section outlines how to analyze any IR spectrum.

Infrared spectrophotometer can be used for the following:

a.      Identfcation functional group

b.      Taking into account the presence of other information such as melting point, boiling point, molecular weight and refractive index to determine the structures and to identify compounds

c.       By using a computer, can identify compounds even mixture of compounds.

infrared spectrophotometry is more widely used for identification of a compound through the group functions. For the purpose of structure elucidation, the wavenumber region 1400 - 4000 cm-1 which is at the left-ir spectrum, an area that is particularly useful for the identification of functional groups, which is the absorption of the stretching vibration. Furthermore, the area just to the right of wave numbers 1400 cm-1 are often very complicated because in this region occurred absorption of stretching vibration and bending vibration, but any organic compound having a Characteristic absorption in this region. It is therefore part of the spectrum is called fingerprint region (fingerprint region). Currently there are two kinds of instruments that ir spectroscopy and FTIR (furier transformation infra red). FTIR is more sensitive and accurate example to distinguish cis and trans forms, conjugated and isolated double bonds and others are in the ir spectrophotometer indistinguishable.

The Theory of NMR: This section explains the theory of NMR spectroscopy at a level appropriate for the sophomore organic chemistry student. Both proton and carbon NMR are covered.

As the name implies NMR (nuclear magnetic resonance, nuclear magnetic resonance), NMR spectroscopy related to the core character of an atom in a molecule is analyzed. NMR spectrometry is basically another form of absorption spectroscopy as well as UV-VIS and IR. The difference with IR and UV-VIS is

Absorption system under the influence of a magnetic field and it is not on UV-VIS and IR. In the NMR energy electromagnetic radiation in the radio frequency region.

  kafein

Working Principle of NMR Spectroscopy

This type of spectroscopy method is based on the absorption of energy by spinning particles in a strong magnetic field. The energy used in the measurement by this method is in the region from 75 to 0.5 m or radio waves at a frequency of 4-600 MHz, depending on the type of core that is measured.

Core that can be measured by NMR, namely:

a. spherical shape

b. spin

c. Spin quantum number = ½

d. Odd number of protons and neutrons, for example: 1H, 19F, 31P, 11B, 13C

In the magnetic field, NMR active nuclei (eg 1H or 13C) absorb at a frequency characteristic of an isotope. The resonant frequency, energy absorption and the signal intensity is proportional to the strength of the magnetic field. For example, at 21 tesla magnetic field, protons resonate at 900 MHz. value of 21 T magnet is considered equivalent to a 900 MHz magnet, although different nuclei resonate at different frequencies.

At the Earth's magnetic field, the same core resonate at audio frequencies. This phenomenon is exploited by the Earth's field NMR spectrometers, which are cheaper and easier to carry. This instrument is used for field work and teaching purposes.

IR/NMR Spectroscopy Problem : This section takes you through the steps that you will need to do to solve for the structure of an organic compound given the IR, NMR, and molecular formula. Each common functional group is discussed in turn and many examples are presented.

3. Dalam isolasi alkaloid, pada tahap awal dibutuhkan kondisi asam atau basa. Jelaskan dasar penggunaan reagen tersebut, dan berikan contohnya sekurang-kurangnya tiga macam alkaloid.

answer : 

An alkaline compound, derived from plants and animals, generally have cicncin heterocyclic (not all members have cincicn nitrogen) and often have biological activity in humans. Not all diklasifikasan nitrogenous compounds as pyridine alkaloids example. Alkaloids kbasaannya different in nature, some properties amfore cntohnya cephalin and psychotrin or even acid recini example. Most dtemukan in plants, although it has now been recorded as also found in fungi (ergot alkaloids), in animal musk deer (muscopyridin), in bacteria p.aeruginosa and some synthetic products.

1. Presipitas Alkaloids

Most alkaloids are precipitated from neutral or acidic solution by a number of reagents containing heavy metals such as mercury (Hg), platinum (Pt), bismuth (Bi) and gold (Au), to form a bond with their salt

Examples of precipitating reagent alkaloid

a. Mayer's reagent (potassium mercury iodide)

Providing the most precipitation creamy besa alkaloid

Caffeine and efredin only at high concentrations.

Ricinin not give precipitation

b. Wagner's reagent (I / KI)

Providing brick red precipitate against almost all alkaloids

c. Hager's reagent (picric acid solution is concentrated)

              Give a yellow precipitate

d. Dragendroff's reagent (solution of potassium bismuth iodide)

Giving up brownish reddish orange color. Also used as a spray reagent for TLC    identification alakaoit

e. Another Reagenisia using acid

Tannat, fosfomolibdat acid, fosfotungstat

2. Specific color reagents

a. Erlich's reagent (Van-Urk reagent)

Solution of p-dimethylaminobenzaldehide in acid, giving distinctive colors birun gray or greenish with Ergot

b. Cerric ammonium sulphate (CAS) under acidic

Alakaoid typical reagents for indole, giving a yellow or reddish orange.

c. Vitali-Mari reagent: characteristic for alkaloids tropan

d. Thaleoquine reaction: typical for alkaloid sinkona

e. Murexide reaction: typical for purine bases

in the first step alkoloid isolation we need acid and base condition. In acid because adding organic acid will make extract produces salt and adding base to lose salt bonding to be free alkaloida

4. Jelaskan keterkaitan diantara biosintesis, metode isolasi dan penentuan struktur senyawa bahan alam . Berikan contohnya.

Answer :

between the three aspects are closely linked, the boisintesis used to obtain new compounds or techniques such as structural changes in the biosynthesis of catechins using 3 x malonyl-CoA will result coas. the biosynthesis of these alone we can use in determining the structure of such ir, uv, and nmr. and for the isolation itself is to recall the components or the active ingredient by using certain solvents. of the insulation itself, we can also determine its structure. if the structure between isolation and biosynthesis have been obtained, the results can be compared

example :

EXTRACTION

Extraction is a way to separate a mixture of several substances into separate components (Winarno et al. 1973). According to Hunt (1988), extraction is a method of separation of one or more of the desired compound or solid solution containing a mixture of such compounds both physically and chemically.

In the process of extraction, solvent diffusion event occurs in the cell material. Solvent into the cell material will dissolve the compound when the solubility of the compound, which is extracted with solvents. In this way will be achieved equilibrium between the solute and solvent. Spending the active ingredient of the material depends on the rate of diffusion of the substance of substances into the solvent, the contact time, and the rate of solvent through the material (Bombardelli 1991).

Harborne (1987) states that the solubility of a substance in a solvent depends on the polarity. The only polar substances soluble in polar solvents as well as non-polar substances only soluble in nonpolar solvents. Selection of solvent in the extraction solvent should pay attention selectivity, the ability to extract the target component, toxicity, ease evaporated, and the price of solvent.

 Isolation of Alkaloids

Alkaloid extracted from the leaves of plants, flowers, fruit, bark, and roots are dried and then crushed. Extraction of alkaloids in general are as follows:

a. Alkaloid extracted with solvents, eg ethanol, and then evaporated.

b. Extracts were obtained inorganic acids to produce a quaternary ammonium salt and then extracted again.

c. Quaternary ammonium salt obtained was treated with sodium carbonate to produce these alkaloids were then extracted with a solvent-free such as ether and chloroform.

d. Mixture - a mixture of alkaloids obtained finally separated in various ways, such as chromatographic methods (Tobing, 1989).

There are other ways to get the alkaloids from the acid solution by absorption using Lloyd reagent, and then eluted with dilute alkali alkaloids. Alkaloid that is hydrophobic absorbed by XAD-2 resin and then eluted with acid or ethanol-water mixture. Many alkaloids which can be precipitated by Mayer's reagent (potassium mercury (II) iodide) or salt Reineccke.

This study used a general way that the isolation of alkaloids extracted with an organic solvent, acidification, formation of quaternary ammonium salts with bases, extraction with organic solvents, and purification using column chromatography, thin layer chromatography, or electronic instruments (IR, GC-MS , UV-Vis)

So after we get isolation results obtained then the structure can be determined