Lecture №1

1. Lecture №1 Alkaloids as medicines. Sources of obtaining, methods of the structure determination. Their chemical classification, general methods of qualitative and quantitative determination. Alkaloids, imidazole’s, pyrolysidine’s, quinolysi(di)ne’s, quinoline’s derivatives, with exocyclic nitrogen atom. ass.Medvid I.I.

2. Definition of alkaloids:: Alkaloids – nitrogen containing organic bases, usually of plant origin, which have an active biological action. Alkaloidsare similar to alkali. Alkaloids - complex derivatives of ammonia, which have replaced hydrogen atom on radicals: tertiary or secondary amines, or derivatives of four substituted ammonium bases. Alkaloids are weak bases. Codeine has the strongest basic properties (К= 9·10-7),caffeine – the weakest (К = 4,1·10-14).

3. Distribution in nature: • Alkaloids, related by structure, often can be found in plants that are close in botanical terms. Mainly in one plant is a mixture of alkaloids (exception – castor plant containing ricynine). Some plants (cinchona, poppy seeds, barberry) containing up to 10-15% of alkaloids. • Localization - most aerial parts of medicinal plants (flowers, fruits, leaves, cortex). Some alkaloids can be moved from one part of plant to another part. Their content in plants depends on the: climate, temperature, altitude above the sea level and others. So the content of ephedrine in Ephedra may change during the year from 0.3% to 2.5%.

4. Historic moments of alkaloid chemistry research: • In 1804 the French pharmacist Sehen allocated morphine from opium as a technical product. • In 1816 professor of the Kharkiv University F.I. Giza allocated quinine. In 1818 year were discovered strychnine and brucine, and a year later - caffeine. • In 1842 y. А.А. Voskresenskiy opened theobromine, and in 1847 J.F. – Fritzsche - hormyn. • A.M. Butlerov and A.N. Vishegradskiy on the basis of their experimental work concluded that all alkaloids are derivatives of pyridine and quinoline.

5. In1881 y. inRussia first synthesis of coniine was conducted. • 1915 y. – Chychybabin with Rodionov began industrial production of opium and other alkaloids. In 1917 y. first alkaloid plant began work in Russia. • Important role in the development of chemistry played A.P. Orekhov and his school.They investigated 1500 species of plants, found more than 250alkaloid containing plants, issuedmonograph "Chemistry of alkaloids”. • N.А. Preobrazenskiyin in 1933 at first made the original synthesis of pilocarpine.

6. Classification of alkaloids Alkaloids are naturally occurring chemical compounds containing basic nitrogen atoms. The name derives from the word alkaline and was used to describe any nitrogen-containing base. Alkaloids are produced by a large variety of organisms, including bacteria, fungi, plants, and animals and are part of the group of natural products (also called secondary metabolites). Many alkaloids can be purified from crude extracts by acid-base extraction. Many alkaloids are toxic to other organisms. They often have pharmacological effects and use as medications and recreational drugs. Examples are the local anesthetic and stimulant cocaine, the stimulant caffeine, nicotine, the analgesic morphine, or the antimalarial drug quinine. Some alkaloids have a bitter taste. Alkaloids are usually classified by their common molecular precursors, based on the metabolic pathway used to construct the molecule. When not much was known about the biosynthesis of alkaloids, they were grouped under the names of known compounds, even some non-nitrogenous ones (since those molecules' structures appear in the finished product; the opium alkaloids are sometimes called "phenanthrenes", for example), or by the plants or animals they were isolated from. When more is learned about a certain alkaloid, the grouping is changed to reflect the new knowledge, usually taking the name of a biologically-important amine that stands out in the synthesis process.

7. Types of the alkaloid classifications • By the chemical structure: • derivatives of pyrrolidine (sthrahidrine, turicine) • derivatives oftropane (atropine, cocaine) • derivatives ofpyperidine (lobeline, coniine) • derivatives ofpyridine (nicotine, anabasine) • derivatives ofpyrrolysidine(platyphylline) • derivatives ofquinolysidine (pahicarpine, lupinine) • derivatives ofquinoline (quinine) • derivatives ofisoquinoline (papaverine, morphine) • derivatives ofindol (reserpine, strychnine) • derivatives ofpurine (caffeine, theobromine, theophylline)

8. derivatives ofthe differentheterocycles (imidazol (pilocarpine), thiazol (agroheline), quinazoline (luotoline А), acridine (rutacridone), azenine (galantamine)); • polypeptide alkaloids (13-, 14-, і 15-member) (buckthorn alkaloids); • alkaloids with exocyclic nitrogen atom(ephedrine, muscarine, spherophysine); • terpenoid alkaloids (acronicyne, actinidine); • steroid alkaloids (solasodine, cholophyllamine);

9. By the ways for their biosynthesis(according to the substances from which they are obtained): • true alkaloids (1-12 group) – which is synthezed from aminoacids and heterocycles are the base of their structure; • proptoalkaloids (13 group) – do not include heterocycles, also are the plant amines and formed from aminoacids; • pseudoalkaloids (14, 15 group) – obtained by others ways different from aminoacids. • By plant sources

10. Classification of alkaloids by Orekhov • Acyclic and alcaloids with exocyclic nitrogen atom (ephedrine hydrochloride, sphaerophysine benzoate, colchamine, colchicine) • Derivatives of pyrrolidine and pyrrolysidine (platyphyllinehydrotartrate):

11. Derivatives of pyridine (nicotine) and piperidine (lobeline, coniine): • Condensed pyrrolidine with piperidine (tropane):

12. Derivatives of quinolysine (cytisine) and quinolysidine (pachycarpine hydroiodide): • Derivatives of quinoline (salts of quinine) and isoquinoline (papaverine hydrochloride, opium alkaloids):

13. Derivatives of indol (physostigmine salicilat, strychnine nitrate, reserpine): • Derivatives of quinazoline:

14. Derivatives of imidazol (pilocarpine hydrochloride): • Derivatives of purine (caffeine, theophylline, theobromine):

15. Diterpene alkaloids (aconite, isoprenoide). • Steroid alkaloids and glicoalkaloids: Nowadays, it is known more than 5000 different alkaloids, while for 3000 of them installed molecular structure

16. Methods of extraction from plant materials • extraction in the form of salts (water, alcohol, tartaric acid); • extraction in the form of basis (NH4OH, NaHCO3); • Distillation of alkaloids bases with aqueous steam (boiling point for which is less than 100 º C).

17. Extraction as salts: to raw material add water or ethanol with few drops of tartaric acid. All alkaloids forms salts with tartaric acid. For purification to this extract add base and all alkaloids form bases, which obtained by organic solutions. Operation of purification repeat few times. Then solvent separated from alkaloids. Sum of alkaloids is separated on individual compounds. Extraction as bases: to raw material add alkali solution (ammonium, sodium hydrocarbonate or carbonate). Alkaloids bases are extracted by organic solutions. Purification realize by transferring alkaloids to salts and then to bases. Operation of purification repeat few times.

18. The methods of separation of the selected amount of alkaloids: • Fractional distillation in vacuum; • By the different solubility of alkaloids – salts and bases; • By the different power of basic properties of alkaloids; • based on the featuresof chemical properties; • By the different ability to adsorption (chromatography); • Method of anticurrent separation.

19. For identification of alkaloids use general, group and specific reaction. • The general reactions conduct with common alkaloid precipitation and special reagents. • Common precipitate reactions based on the ability of alkaloids as bases to give simple or complex salt with different, more often complex acids, salts of heavy metals and others.These products are usually not soluble in water, so calledprecipitate.

20. General alkaloid precipitate reagents: • Dragendorph reagent – BiI3+KI↔K[BiI4] - SPU • Lyugol, Vagner, Bushard reagents– sol. І2in КІ in different concentraions • Maier reagent – HgI2 + 2KI↔K2[HgI4] • Marme reagent (solutionCdI2в KI) • Zonnenshten reagent - Н3Р04 • 12Мо03 • 2Н20 • Sheibler reagent - Н3Р04 • 12WоО3 • 2Н20 • Berthran reagent - SiO2 • 12Wо03 • 4Н20 • 5% Tannin solution (freshly prepared). • Saturated solution of picric acid.

21. Special (painted) reagents on alkaloids: • Conc. H2SO4. • Conc. HNO3. • Erdman reagent (H2SO4 conc.+HNO3 conc.). • Phrede reagent ((NH4)2MoO4+H2SO4 conc.). • Marki reagent (HCOH+H2SO4 conc.). • Mandelin reagent (NH4VO3+H2SO4 conc.). • Sodium nitroprusside (Na2[Fe(CN5)No]·2H2O). • Vazitsky reagent (solution of p-dimethylaminobenzaldehyde in conc. H2SO4).

22. Methods of the quantitative determination of alkaloids: • Acid-base titration in nonaqueous environment– for the quantitative determination of both salts and bases. • Acid-base titration: а) acid-base titration, direct titration of acids and bases; b) acid-base back-titration for determination of basesby reverse titration; c) alkalimetry – titration of alkaloids salts by alkali in water-alcohol medium in the presence of phenolphthalein (with or without the usage of organic solvent that does not move with water for extraction of alkaloid bases) d) Alkalimetry by the substituent • Gravimetric method • Methods based on individual chemical properties of alkaloids. • Physico-chemical methods.

23. Alkaloids with exocyclic nitrogen atom Ephedrinehydrochloride(Ephedrini hydrochloridum) (-) 1-Phenyl-2-methylaminopropanol-1 hydrochloride Sphaerophysinebenzoate (Sphaerophysinibenzoas) 1-guanidino-4-(isoamylene-11)-aminobutanedibenzoate

24. L-ephedrine (cys-isomer, left-rotation) D-pseudoephedrine (trans-isomer, right-rotation) Ephedrine contains in different types of Ephedra, together with its stereoisomers

25. Ephedra monosperma

26. Obtaining of ephedrine by synthetic method Benzene with chloroanhydride of chloropropanoic acid is condensed at the presence of AlCl3(Fridel-Crafts reaction). Obtained chloroethylphenylketone condensed with methylamine, aminoketone is formed which reduced to ephedrine:

27. Sphaerophysa salsula

28. Ephedrine hydrochloride Colorless needle crystals or white crystalline powder, odorless, with bitter taste. Easily soluble in water (so under the action of alkali precipitate is not falls - the difference from other alkaloids), soluble in alcohol, practically insoluble in ether. Sphaerophysine benzoate White crystalline powder with bitter taste. Soluble in water, alcohol, alkalis, insoluble in ether and chloroform. Physical properties

29. Ephedrine hydrochloride Reactions of chlorides WithCuSO4at the presence ofNaOH – blue complex compound (At the shaking of this solution with ether, ether layerpaints in red-violet color, water layerkeeps blue color). At the heating with potassium ferrocyanide crystal smell of benzaldehyde appears (bitter almond). Specific rotation: from -33° to -36° (5 % water solution). Sphaerophysine benzoate With HCl – white precipitate of benzoic acid falls. At the boiling with alkalis urea separated and thenNH3 With sodium nitroprusside alkali solution, laterHCl – cherry-red color which quickly disappears. Identification

31. Ephedrine hydrochloride Acidimetric titration in nonaqueous medium in the presence of mercury (II) acetate (indicatorcrystal violet, Е=М.m). Alkalimetric titration alcohol-chloroform medium (Е=М.m). Argentometry by the linked HCl (Phayans’ methodwith the usage of bromothymol blue indicator) (Е=М.m). Sphaerophysine benzoate Acidimetric titration in nonaqueous medium in the presence of ice acetic acid (indicatorcrystal violet, Е=М.m/2). Bromatometry, direct titration (Е=М.m/2). Quantitative determination

32. Ephedrine hydrochloride Drastic compound. In tightly closed container (TCC) whichkeeps from the action of light. Sympathomimetic (vasoconstrictive, bronchodilating) mean. By the action it is close to adrenaline, has specific stimulatory action on CNS. Internallyby 0,025-0,05g 2-3 timesperday, i/m або i/v (intravenous)by 1 ml of 5% solution. Included to the content of Theophedrine tablets, Ephatineaerosol, Solutan and Broncholitine syrups. Sphaerophysine benzoate Drastic compound. In tightly closed container with orange glass, in the place protected from lightв. Ganglioblockator mean, uterine muscle stimulant. Used for the treatment of hypertension and strengthening of maternity activity by 0,03g 2-3 times per day ori/mby 1ml of 1% solution. Storage, application

33. Colchamine Colchicum autumnale Colchamineandcolchicine – alkaloids from different types of Colchicum, toxic compounds, use as ointments in the treatment of skin cancer

34. Alkaloids – derivatives of imidazol Pilocarpine hydrochloride (Pilocarpini hydrochloridum) α-Ethyl-β-(1-methylimidazollyl-5-methyl)- γ-butyrolactonehydrochloride (3S,4R)-3-Ethyl-4-[1-methyl-1Н-imidazol-5-yl)methyl]dihydro-3Н-furan-2-onehydrochloride 5(3-ethyl-4,5-dihydrofuranone-2)-methylene-1-methylimidazolhydrochloride

35. Pilocarpus Jaborandi Was obtained in 1875 y. Diminished in size dry leaves extracted by acidified alcohol. Distilled alcohol from the extract and separated free alkaloids which transfer to nitrates and then to hydrochlorides. Alkaloids are separated by the factional crystallization or chromatographic method. Obtaining of pilocarpine

36. Pilocarpine was synthezed in 1933 y. by А.M. Preobrazenskiy from homopilopic acid, which obtained from diethyl ether of ethylamber acid С2Н5СН(СООС2Н5)СН2СООС2Н5 by the following scheme:

37. Physical properties of pilocarpine hydrochloride Optical active, has two asymmetric carbon atoms. Colorless crystals or white crystalline powder, odorless.Hygroscopic. It is easy soluble in water, easily soluble in alcohol, practically insoluble in ether and chloroform. Identification of pilocarpine hydrochloride • Substance gives reaction to chlorides. • Chelch sample. Reaction of the formation of abovechromic acids (mixture Н2О2, Н2SО4 conc., К2Сr2О7) and chromoperoxide (CrO5), which with pilocarpine base forms blue-violet complex compound soluble in chloroform. At the absence of pilocarpine colored product is not extracted by chloroform. • Legal reaction on lactone ring. With sodium nitroprusside in alkali medium – cherry-red color, which does not disappear when you add excess of chloride acid.This reaction can be used for the photocoloeimetric determination of pilocarpine in 1 % water solutions.

38. 4. Specific rotation from +88,5° to +91,0° (2 % water solution). 5. Hydroxame reaction (presence of the lactone ring – butyrolactone): 6.Preparation at the grinding with calomel becomes black as a result of formation of metallic mercury at the pilocarpine oxidation: Pilocarpine Pilopic acid+ Methylurea

39. Quantitative determination of pilocarpine hydrochloride • Acid-base titration in nonaqueous medium in the presence of mercury (II) acetate (Е=М.m). • Alkalimetry in alcohol medium (Е=М.m). • Iodometry, reverse titration (after the separation of polyiodide precipitate). Storage Poison compound.In tightly closed container, which keeps from the light and moisture. Application Cholinolytic (miotic) mean. Prescribed as eye drops (1-2% solution) or ointment for the treatment of glaucoma.

40. Alkaloids – derivatives of pyrrolysidine Platyphyllinehydrotartrate (Platyphyllini hydrotartras)

41. To establish the structural formula of platyphylline you should study the products of its hydrolysis. At the heating with alcoholic solution of alkali platyphylline decomposes on aminoalcoholplatynecyne and synecionilic acid: So platyphylline – cyclical diester, in which two hydroxyl groups of platynecyne are etherificated by synecionilic acid.

42. Senecio plathyphylus Platyphyllineand his companionseneciphylline are derivatives of 1-methylpyrolysidine, was extracted in 1935 y. by О. P. Orekhov і R. А. Conovalovafrom the roots and herbof Senecio plathyphylus.

43. Properties of platyphyllinehydrotartrate A white odorless crystalline powder with weak or specific smell and bitter taste.  Easily soluble in water, very little soluble in alcohol, practically insoluble in chloroform and ether. Identification of platyphyllinehydrotartrate • Speciofic rotation from -38° to -40° (5 % water solution). • With Dragendorph reagentforms orange precipitate. • With Mayer reagent forms white precipitate. • Formation of iron (III) hydroxamate red color (ester group).

44. Substance gives reaction on tartrates: a) with potassium salts – white crystal precipitate; b) with 0,1 М AgNO3solution – white precipitate. To the one part of solution add dil. НNO3 – precipitated dissolves; at the heating of second part of precipitate with NH4OH on the walls of the tube forms silver mirror”, cases by the properties of tartaric acid; c) with β-naphthalenein the presence of Н2SО4 conc. Green color appears at heating; if instead β-naphthaleneused resorcinol – red-violet color of aurine dye-stuff :

45. Aurine dye-stuff

46. Quantitative determination of platyphyllinehydrotartrate • Acid-base titration in nonaqueous medium, a direct titration, the indicator - crystal violet (Е=М.m). • Alkalimetry in alcohol-chloroform medium (Е=М.m). • Iodometry, back-titration (by the reaction of formation of polyiodide in saturated solution of NaCl). • Photocolorimetry – on the basis of the reactions with common alkaloid color reagents. • Extraction-photometric – determination of platyphylline hydrotartrate in the injection solution and tablets by the reaction with tropeoline 000-ІІ. • UV- spectrophotometry, GLCH.

47. Purity test Seneciphylline - unacceptable impurity: there should be no distraction while adding of 5% ammonia solution. Storage Poison compound.In tightly closed container. In dry place. Application m-Cholinolytic (spasmolytic, midriatic) mean. At the spasms of smooth muscles of the abdominal cavity, spasms of bloodvessels, bronchial asthma and others. Highest one-time dose. - 0,01 g, highest daily dose - 0,03 g. Subcutaneous (s/c) 0,2% 1,0 ml, eye drops -1%.

48. Alkaloids – derivatives ofquinolysine Cytisine (Cytisinum) Derivative of 1,2,3,4 tetrahydroquinolysine-6, condensed with piperidine White or slightly yellowish crystalline powder. Easily soluble in water, alcohol and chloroform.

49. Cytisus laburnum Thermopsis(Thermopsis lanceolata) Cytisine is extracted from seeds by 60% alcohol acidified by acetate acid. Extract is evaporated to the dry state, added to the alkali residue and extract alkaloids by chloroform. Chloroform extract evaporated to the dry state and separated alkaloids by factional crystallization or usage of the ion-exchange resins. Substance is purified by the distillation in vacuum.

50. Identification of cytisine • By the physico-chemical constants: melting point, specific rotation. • Nitration reaction of the aromatic ring with subsequent reduction of the nitro-group to the amino-group and azodye formation. • With solution of cobalt (II) nitrate - blue-green sediment. • With solution of iron (III) chloride - red color, which disappears when you add water. • The reaction of alkaloids with Dragendorph reagent.