Jumat, 30 November 2012

Nicotine

Introduction to Nicotine

Nicotine is named after the tobacco plant Nicotiana tabacum, which in turn is named after the French ambassador in Portugal, Jean Nicot de Villemain, who sent tobacco and seeds to Paris in 1560, and who promoted their medicinal use. Nicotine was first isolated from the tobacco plant in 1828 by physician Wilhelm Heinrich Posselt and chemist Karl Ludwig Reimann of Germany, who considered it a poison. Its chemical empirical formula was described by Melsens in 1843, its structure was discovered by Adolf Pinner and Richard Wolffenstein in 1893, and it was first synthesized by Amé Pictet and A. Rotschy in 1904.


Structure of Nicotine

The molecular formula for nicotine is C10H14N2.

 
Nicotine is a hygroscopic, oily liquid that is miscible with water in its base form. As a nitrogenous base, nicotine forms salts with acids that are usually solid and water soluble. Nicotine easily penetrates the skin. As shown by the physical data, free base nicotine will burn at a temperature below its boiling point, and its vapors will combust at 308 K (35 °C; 95 °F) in air despite a low vapor pressure. Because of this, most of the nicotine is burned when a cigarette is smoked; however, enough is inhaled to cause pharmacological effects.
 

Biosynthesis

The biosynthetic pathway of nicotine involves a coupling reaction between the two cyclic structures that compose nicotine. Metabolic studies show that the pyridine ring of nicotine is derived from nicotinic acid while the pyrrolidone is derived from N-methyl-Δ1-pyrrollidium cation. Biosynthesis of the two component structures proceeds via two independent syntheses, the NAD pathway for nicotinic acid and the tropane pathway for N-methyl-Δ1-pyrrollidium cation.

The NAD pathway in the genus nicotiana begins with the oxidation of aspartic acid into α-imino succinate by aspartate oxidase (AO). This is followed by a condensation with glyceraldehyde-3-phosphate and a cyclization catalyzed by quinolinate synthase (QS) to give quinolinic acid. Quinolinic acid then reacts with phosphoriboxyl pyrophosphate catalyzed by quinolinic acid phosphoribosyl transferase (QPT) to form nicotinic acid mononucleotide (NaMN). The reaction now proceeds via the NAD salvage cycle to produce nicotinic acid via the conversion of nicotinamide by the enzyme nicotinamidase.

The N-methyl-Δ1-pyrrollidium cation used in the synthesis of nicotine is an intermediate in the synthesis of tropane-derived alkaloids. Biosynthesis begins with decarboxylation of ornithine by ornithine decarboxylase (ODC) to produce putrescine. Putrescine is then converted into N-methyl putrescine via methylation by SAM catalyzed by putrescine N-methyltransferase (PMT). N-methylputrescine then undergoes deamination into 4-methylaminobutanal by the N-methylputrescine oxidase (MPO) enzyme, 4-methylaminobutanal then spontaneously cyclize into N-methyl-Δ1-pyrrollidium cation.

The final step in the synthesis of nicotine is the coupling between N-methyl-Δ1-pyrrollidium cation and nicotinic acid. Although studies conclude some form of coupling between the two component structures, the definite process and mechanism remains undetermined. The current agreed theory involves the conversion of nicotinic acid into 2,5-dihydropyridine through 3,6-dihydronicotinic acid. The 2,5-dihydropyridine intermediate would then react with N-methyl-Δ1-pyrrollidium cation to form enantiomerically pure (–)-nicotine.


Isolation of Nicotine
Nicotine, (S)­-3­-(1­-methyl­-2­-pyrrolidinyl) pyridine, is the most abundant of the volatile alkaloids in the tobacco leaf. The primary commercial source of nicotine is by extraction from the plant Nicotinia tabacum and Nicotinia rustica. Nicotine acts on nicotinic cholinergic receptors, affects most organ systems in the body and is a highly addictive drug. Nicotine normally makes up about 5 percent of a tobacco plant, by weight. Cigarettes contain 8 to 20 milligrams (mg) of nicotine (depending on the brand), but only approximately 1 mg is actually absorbed in the human body.

Procedure:
  1. Weigh 10 g of cigarettes leaves in beaker.
  2. Add 100ml NaOH solution and stir very well for 15 min. 
  3. Filter in Buchner using glass wool and press the cigarettes very well by using other beaker. 
  4. Transfer the cigarettes again to beaker. 
  5. Add 30ml DW and stir and filter again. 
  6. Collect the filtrate together. (If there is any impurities re-filter). 
  7. Transfer the filtrate to the SF and extract by 25ml ether. 
  8. Repeat the extraction 3times. 
  9. Gather the 4 filtrates in conical flask. 
  10. Dry by using 1teaspoon anhydrous potassium carbonate. 
  11. Filter. 
  12. Evaporate ether on water bath.(Avoid extra heat because nicotine is hydrolyzed by extreme heating).
  13. After evaporation of ether add 4ml methanol to dissolve the resulted oil. 
  14. Add 10ml saturated picric acid solution. 
  15. Cool in an ice bath to precipitate the  nicotine di picrate crystals. 
  16. Filter; allow drying and weighing the product.

 

Sabtu, 24 November 2012

Natural Products Chemistry


Mid Semester Exam
Subject                 : Natural Products Chemistry
Credit                    : 2 credits
Lecturer                : Dr. Syamsurizal, M.Si
Day / Date           : Saturday, 24 november 2012
Time                       : 15:30 till 09:00 am  (26 november 2012)

  1. 1.      Put forward your ideas how to convert a compound of natural ingredients that do not have the potential (inactive) can be made into superior compounds that have a high potential for biological activity. Give the example.
    Answer:
                One way to change a compound of natural ingredients that do not have the potential (inactive) can be made into a superior compound that has the potential of high biological activity is the preservation and drying, for example on the plant crown god. God petals contains a variety of chemicals, one of which is a flavonoid. Flavonoids are compounds containing C15 consists of two phenolic nuclei linked to three carbon units. Flavanoid function in the crown of the gods for blood circulation throughout the body and prevent blockages in blood vessels, reduce cholesterol content and reduce penumbunan fat on blood vessel walls, reducing the levels of risk of coronary heart disease, contains anti-inflammatory (anti-inflammatory), serves as an anti-oxidant, helps relieve pain in case of bleeding or swelling.
    Biologically flavonoids play an important role in relation to the pollination of plants by insects. A number of flavonoids have a bitter taste to be able to resist a certain kind of worm. Trees Mahkota Dewa (Phaleria macrocarpa) is known as one of the medicinal plants in Indonesia. Originally from Papua / Irian Jaya. Plant or tree crown of God is often planted as a shade plant. The size is not too big to reach 3 feet tall, has bright red fruit that grows from the main trunk to the branches.
    To extend the shelf life Phaleria, preservation can be done in several ways such as refrigeration, canning, and drying. Drying is done on Phaleria aimed at reducing the moisture content in the material, so that the remaining water can not be used as a medium for microbial life destroyer is in the material, in other words, to extend the shelf life of these Phaleria. Proper drying conditions will menentukn drying high quality results.

  2.  Explain how the idea of a compound of natural ingredients that have a high biological potency and prospective for the benefit of sentient beings can be synthesized in the laboratory.
    Answer:
                A compound of natural ingredients that have a high biological potency and prospectively for the living beings kemaslatan Phaleria used as a cure various kinds of diseases.
    An example is used for the disease:

    Dysentery
    Boil Phaleria skin is dried (15 g) with two cups of water to boil for 15 minutes. Once cool, strain clan drinking water as well. Do it 2-3 times a day.
    Psoriasis
    Cut the fresh Phaleria (three pieces), seeds removed, then sliced ​​thin and dry in the sun to dry. Boil these bulbs with one liter of water over high heat. Once boiling, reduce heat and simmer until the remaining quarter. Once cool, strain and drink the water twice a day, each half. If symptoms of poisoning, lower the dose or discontinue use.
    Eczema, hives
    Wash fresh petals god taste, and grind until smooth. Stick it on the sick, and dressing. Replace 2-3 times a day.
    How to extract flavonoids contained in the crown of God laboratory are:
    • Created solution BAW BAW 4:1:5 and 9:2:6 in the funnel
    • To be taken the next day the solution is at the bottom
    • Prepared 4 chambers each containing BAW 4:1:5, 9:2:6 BAW, n-hexane, and methanol
    • filter paper inserted into each chamber and allowed to stand until saturated
    • Weighed 10 grams of powder Phaleria
    • input into the tool percolator
    • Extracted using solvents n-hexane 250 mL
    • The residue was extracted again using a percolator with a methanol 80% to clear
    • Accommodated n-hexane and non-polar compounds
    • The powder was taken and dried, soaking again by adding methanol as 200ml
    • It was found that the methanol extract of flavonoids contained therein
    • methanol extract was concentrated using a rotary evaporator
    • Obtained extract concentrated and stored in sealed containers
    • concentrated extract spotted on TLC plates 4
    • Each plate is inserted into the chamber containing the BAW 4:1:5, 9:2:6 BAW, n-hexane
    • Detected spots under visible light and UV light 254 nm and 366 nm
    • Noted the color spots and Rf of each developer used
    • Determined the best and eluent used for separation by preparative TLC

  3.  Explain the basic rules in choosing a solvent for the isolation and purification of a compound of natural ingredients. Give the example for 4 classes of compounds of natural products: terpenoids, alkaloids, flavonoids, and steroids.
    Answer:
                In choosing a solvent for the isolation and purification of a compound ingredient is a natural solvent that meets the following requirements:
    a. Dissolves perfect component of a compound of natural ingredients contained in the plant.
    b. Mempunuyai low boiling point.
    c. Does not mix with water.
    d. Inert, does not react with the components of a compound of natural ingredients.
    e. Has a boiling point, when evaporated leaving no residue.
    f. Price is cheap.
    g. Whenever possible, non-flammable.
    h. More volatile

    Isolation of flavonoids from green tea leaves using solvent diethyl ether.
    In the solvent extraction process should choose the appropriate type of flavonoid required so should consider the polarity of the solvent. Types of non-polar flavonoids (eg, isoflavones, flavanones, flavones and flavonols alcohol) was extracted using chloroform, dichloromethane, diethyl ether, or ethyl acetate, while the flavonoid glycoside and aglycone would be more appropriate extracted with alcohol or alcohol-water mixture. To glycosides increased solubility if the water or alcohol-water mixture. Generally most of the extraction process materials containing flavonoids is done simply with the addition of direct solvent extraction.

    Isolation of alkaloid compound that is caffeine from the black waste using chloroform solvent because it can produce high caffeine marinade.

    Isolation of compounds from the leaves of tread liman steroid use ethanol because it can dissolve almost all secondary metabolic compounds. Besides ethanol is also volatile so easily evaporated from the extract.

    Isolation of antibacterial compounds active terpenoids in herb meniran using solvent methanol and n-hexane. Why use methanol, because methanol is a semi-polar solvent that can dissolve many compounds and methanol are also more volatile and easier to come by than other solvents.

     
  4.  Explain the basic starting point for the determination of the structure of an organic compound. When the compounds of natural ingredients such as caffeine tersebuat is. Put forward your ideas matter - whatever the subject matter is required in determining the overall structure.
    Answer:
                for preliminary identification of any isolate flavonoid compounds were performed by observing the color of fluorescence under ultraviolet light before and after the addition of ammonia vapor, followed by ultraviolet spectrophotometer to see the slide batokromik after reacted with specific reagents, the obtained results as shown in Table 1 and Figure 4, 5, 6, 7, 8, and 9. From the results of this analysis can be discussed as follows:
    Chromatogram of ethanol extract fractionation results
    Description:
    1 = fraction of chloroform, ethyl acetate fraction 2 =, 3 = n-butanol Fraction III, 4 = n-Butanol Fraction I, 5 = n-butanol Fraction II, 6 = fraction of water.
    Developer: n-butanol-water-as.asetat (60:22:1,2)
    Apparition spotting: Lar. Aluminum chloride 5%, UV rays and ammonia vapor
    Data shift the wavelength of maximum absorption isolate compounds
    The results of this preliminary investigation on compound leads flavonol glycosides substituted with OH-3 and OH-4 have ', or flavonoids with OH-5, or flavanones with OH-5 or kalkon without OH on ring B. It is based on the dark purple spots under ultraviolet UV, and the color changed to yellow after reacted with ammonia vapor. In methanol solution of this compound gives two maximum absorption bands are bands I and II 258.0 358.0 indicating that the compound was flavones or flavanones. The existence of the shoulder on the maximum absorption bands II showed the presence of 2 or more O atoms in the ring B. With the addition of sodium hydroxide maximum absorption bands I to 413.0, a shift batokromik 55 nm and without a decrease in intensity, suggesting the existence of OH-4 'free. The formation of new bands with maximum absorption 333 indicate the presence of OH-7 free. So the compound leading to flavonol not kalkon.
    UV spectrum of flavonoids SA-DE-1




    UV spectrum of flavonoids SA-DE-2

    With the addition of sodium acetate maximum absorption bands II shifted 15 nm with no decrease in intensity, this further strengthens the presence of free OH-7, with the addition of boric acid to sodium acetate solution I shifted maximum absorption bands at 22 nm, it showed no ring B ortodihidroksi . The addition of aluminum chloride resulted in a shift of maximum absorption bands batokromik I was 53 nm, indicating the existence of OH-5 free without oxygenation at positions 6 and shift decreases on the addition of hydrochloric acid to the tape I showed ortodihidroksi group. From the above data, the structure of the lead compound flavonol OH-3 substituted with OH at position C atom number 5, 7, 4 ', 5', and by looking at the results of the derivatization and infrared spectra of compounds SA-DE-1 leads to the structure of the compound routine. Results derivatization and infrared spectrum can be seen in Figure 10, 11, 12, 13, 14, 15, 16, and 17.
    The results of the preliminary investigation isolates SA-DE-2 with a look at the dark purple spots under UV light and turns yellow with ammonia vapor, and the maximum absorption bands I 348.0 nm and 267.0 nm bands II in methanol, then this compound leads the structure of the flavonol 3-OH substituted or kalkon. With the addition of sodium hydroxide, the maximum absorption bands I batokromik shifted by 53 nm to 401.0 nm with no reduction in intensity,


    UV spectrum of flavonoids SA-DE-3