Organic Chemistry Compound
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Questions and Answers

What is the common use of Ranitidine and Famotidine?

  • Treatment of diabetes
  • Treatment of cancer
  • Treatment of heartburn and peptic ulcer (correct)
  • Treatment of heart failure

    • What is the difference in potency between Ranitidine and Cimetidine?

  • Ranitidine is 50 times more potent than Cimetidine
  • Ranitidine is 10 times more potent than Cimetidine
  • Ranitidine is 5 times more potent than Cimetidine
  • Ranitidine is 100 times more potent than Cimetidine (correct)

    • What is the structural difference between Ranitidine and Cimetidine?

  • The nitromethylene unit is added to the substituted guanidine analogs
  • The nitromethylene unit replaces the N-cyanoimino group (correct)
  • The nitromethylene unit is removed from the substituted guanidine analogs
  • The nitromethylene unit replaces the sulfanyl group

    • What is the brand name of Famotidine?

    <p>Pepcid</p> Signup and view all the answers

    What is the difference in potency between Famotidine and Ranitidine?

    <p>Famotidine is 15-20 times more potent than Ranitidine</p> Signup and view all the answers

    What is the structural difference between Nizatidine and Ranitidine?

    <p>Nizatidine has a thiazol-4-yl group instead of a furan-2-yl group</p> Signup and view all the answers

    What is the brand name of Ranitidine?

    <p>Zantac</p> Signup and view all the answers

    What is the common functional group in Ranitidine, Nizatidine, and Famotidine?

    <p>Sulfanyl group</p> Signup and view all the answers

    What is the effect of inhibiting the ATPase irreversibly by Omeprazole?

    <p>It causes gastric carcinoma</p> Signup and view all the answers

    What is the characteristic of Cyproheptadine (Periactine)?

    <p>It is an antihistaminic with sedative effect</p> Signup and view all the answers

    What is the structural feature of Omeprazole that allows it to exist as either the (S)- or (R)-enantiomers?

    <p>A tricoordinated sulfonyl sulfur in a pyramidal structure</p> Signup and view all the answers

    What is the name of the drug that is a racemate, an equal mixture of the two enantiomers?

    <p>Omeprazole</p> Signup and view all the answers

    What is the function of Ketotifen (Zaditen)?

    <p>It is a mast cell stabilizer</p> Signup and view all the answers

    What is the characteristic of Olopatadine (Patanol)?

    <p>It is a mast cell stabilizer</p> Signup and view all the answers

    What is the essential feature for the activity of Proton Pump Inhibitors?

    <p>Substituted benzimidazole, substituted pyridine and sulfinyl chain connecting the two rings</p> Signup and view all the answers

    What is the effect of benzimidazole substitution with electron donating group?

    <p>It increases the activity</p> Signup and view all the answers

    What is the characteristic of 2nd Generation H-1 blockers?

    <p>They have low affinity to the central muscarinic and adrenergic receptor</p> Signup and view all the answers

    What is the characteristic of Terfenadine (Triludan)?

    <p>It might cause life threatening arrhythmia</p> Signup and view all the answers

    What is the effect of 4-fluoro alkoxy substitution on pyridine ring?

    <p>It increases the biological activity</p> Signup and view all the answers

    What is Fexofenadine (Telfast)?

    <p>It is the active metabolite of Terfenadine</p> Signup and view all the answers

    What is the primary location of H3 receptors in the body?

    <p>Brain</p> Signup and view all the answers

    What is the effect of H3-antihistaminics?

    <p>Stimulant and cognition-modulating</p> Signup and view all the answers

    What is the characteristic of Azatadine?

    <p>It is an antihistaminic with sedative effect</p> Signup and view all the answers

    What is the characteristic of Phenothiazine?

    <p>The N atom is replaced by SP2 carbon</p> Signup and view all the answers

    What is the essential feature of the imidazole ring in H-2 receptor antagonists?

    <p>Free NH is essential</p> Signup and view all the answers

    What is the significance of the sulfur atom in the intermediate chain of H-2 receptor antagonists?

    <p>It increases the potency of the molecule compared to carbon and oxygen congeners</p> Signup and view all the answers

    What is the characteristic of the terminal polar non-basic group in H-2 receptor antagonists?

    <p>It is a urea-like end group</p> Signup and view all the answers

    What is the mechanism of action of proton pump inhibitors?

    <p>They irreversibly inhibit the H+/K+ ATPase enzyme</p> Signup and view all the answers

    What is the general structure of a proton-pump inhibitor?

    <p>Methyl or unsubstituted</p> Signup and view all the answers

    What is the significance of the acidic conditions of the canaliculi of parietal cells in the mechanism of action of proton pump inhibitors?

    <p>It converts the proton pump inhibitors to achiral products</p> Signup and view all the answers

    What is the treatment indication of omeprazole?

    <p>Dyspepsia, peptic ulcer, and gastroesophageal reflux</p> Signup and view all the answers

    What is the significance of the nitromethylene group in H-2 receptor antagonists?

    <p>It increases the potency of the molecule</p> Signup and view all the answers

    What is the additional effect of Antazoline besides anti-histaminic effect?

    <p>Local anesthetic effect</p> Signup and view all the answers

    What is the common feature of Pheniramine and its analogues?

    <p>They are all propylamine derivatives</p> Signup and view all the answers

    Which of the following is used as a maleate salt?

    <p>Chlorpheniramine</p> Signup and view all the answers

    What is the relative activity of propylamine derivatives compared to ethylene diamine derivatives?

    <p>5 times more active</p> Signup and view all the answers

    What is the chemical structure of Pheniramine?

    <p>N,N-Dimethyl-3-phenyl-3-(2-pyridinyl)propanylamine</p> Signup and view all the answers

    What is the main use of Antazoline?

    <p>In eye preparations</p> Signup and view all the answers

    Which of the following is NOT a propylamine derivative?

    <p>N,N-Dimethyl-N'-(2-thienylmethyl) ethylene diamine</p> Signup and view all the answers

    What is the correct chemical structure of Clemizole?

    <p>1-[(4-Chlorophenyl)methyl]-2-(pyrrolidin-1-yl-methyl)benzimidazole</p> Signup and view all the answers

    Study Notes

    Antihistamines

    • Antazoline: has local anesthetic effect and is used in eye preparations
    • Clemizole: has anti-histaminic effect
    • Propylamine derivatives:
      • Pheniramine: N,N-dimethyl-3-phenyl-3-(2-pyridinyl)propanylamine
      • Chlorpheniramine: mainly used as maleate salt
      • Bromo-pheniramine: 3 times more active than ethylene diamine class
    • Phenothiazine: replacing N atom with SP2 carbon
    • Cyproheptadine (Periactine): has antihistaminic and sedative effects
    • Azatadine: has antihistaminic effect
    • Ketotifen (Zaditen): mast cell stabilizer, used as anti-histaminic with long duration of action
    • Olopatadine (Patanol): mast cell stabilizer, used to treat itching associated with allergic conjunctivitis

    2nd Generation H-1 blockers

    • Characteristics:
      • Improved peripheral H-1 selectivity
      • Little affinity to central muscarinic and adrenergic receptor
      • Long acting mainly due to formation of active metabolites
      • Chemically unrelated
      • More hydrophilic, so have decreased CNS side effects
    • Terfenadine (Triludan): used for treatment of allergic conditions, but not used anymore due to life-threatening arrhythmia
    • Fexofenadine (Telfast): active metabolite of Terfenadine

    H-2 receptor antagonists

    • Ranitidine (Zantac): 100 times more potent than Cimetidine
    • Nizatidine (Axid): commonly used for treatment of heartburn and peptic ulcer
    • Famotidine (Famotac / Pepcid): 15-20 times more potent than Ranitidine
    • Lafutidine: chemical name and synthesis
    • Roxatidine (Roxit): chemical name and synthesis

    SAR of H-2 receptor antagonists

    • Basic heteroaromatic ring (if imidazole, free NH is essential)
    • Replacement for the imidazole ring with other heteroaromatic rings resulted in other useful analogs
    • Flexible intermediate chain in which the NH side chain must be separated by 4 carbons or equivalent atoms from the heterocyclic ring
    • Terminal polar non-basic group (Urea like end group)
    • N-cyanoguanidine substituent
    • Nitromethylene group replaces N-cyanoimino group in the substituted guanidine analogs, increasing potency

    Proton Pump Inhibitors (Anti-Ulcer agents)

    • More effective than H-2 blockers in suppressing gastric acid secretion
    • Irreversibly inhibit the H+/K+ ATPase enzyme
    • General structure of a proton-pump inhibitor: methyl or unsubstituted
    • Mechanism of action: conversion to achiral products which react with a cysteine group in H+/K+ ATPase, thereby inhibiting the ability of parietal cells to produce gastric acid

    Proton Pump Inhibitors

    • Omeprazole (Losec): prototype of this group, used for treatment of dyspepsia, peptic ulcer, gastroesophageal reflux, and Zollinger-Ellison syndrome
    • Esomeprazole (Nexium): enantiomer of Omeprazole
    • Rabeprazole (AcipHex):
    • Lansoprazole (Prevacid):
    • Pantoprazole (Pantoloc):

    SAR of Proton Pump Inhibitors

    • Substituted Benzimidazole, substituted pyridine, and sulfinyl chain connecting the two rings are essential for activity
    • Benzimidazole substitution with electron-donating group increases activity
    • Benzimidazole substitution with electron-withdrawing group decreases activity
    • 4-Methoxy group on pyridine ring increases biological activity
    • 4-Fluoro alkoxy substitution on pyridine ring results in strong inhibitory activity

    H-3 receptor antagonists

    • Drugs used to inhibit action of histamine at the H3 receptor
    • H3 receptors are primarily found in the brain and are inhibitory autoreceptors
    • H3-antihistamines have stimulant and cognition-modulating effects

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    Description

    Identify the chemical structure and properties of a complex organic compound, N,N-Dimethyl-N'-pyridin-2-yl-N'-(2-thienylmethyl) ethylene diamine.

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