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Questions and Answers
What type of addition occurs during the hydroboration of alkenes?
What type of addition occurs during the hydroboration of alkenes?
- Radical addition
- Electrophilic addition
- Anti addition
- Syn addition (correct)
In the reduction of alkynes using hydroboration, what is the end product when NaOH and H2O2 are used?
In the reduction of alkynes using hydroboration, what is the end product when NaOH and H2O2 are used?
- Aldehyde (correct)
- Alkene
- Ketone
- Alcohol
What type of compound is produced when borane is transformed in the presence of NaOH?
What type of compound is produced when borane is transformed in the presence of NaOH?
- Alkyl bromide
- Phenol
- Carboxylic acid
- Alcohol (correct)
What is the key application of bioisosteres mentioned in the context?
What is the key application of bioisosteres mentioned in the context?
Which combination is referred to as a prodrug in the content provided?
Which combination is referred to as a prodrug in the content provided?
What method is used to transform borane into alcohol?
What method is used to transform borane into alcohol?
Which compound is a bioisostere listed in the content?
Which compound is a bioisostere listed in the content?
In the reduction of alkynes, which of the following reactants is key for the hydroboration step?
In the reduction of alkynes, which of the following reactants is key for the hydroboration step?
What is the role of NaOH in the transformation of borane to alcohol?
What is the role of NaOH in the transformation of borane to alcohol?
What indicates a significant increase in tubulin inhibition for the compounds mentioned?
What indicates a significant increase in tubulin inhibition for the compounds mentioned?
What is the pKa value that corresponds to the thiol group RSH?
What is the pKa value that corresponds to the thiol group RSH?
Which compound is classified as an example of a sulfonamide?
Which compound is classified as an example of a sulfonamide?
Which of the following statements about the bond lengths is correct?
Which of the following statements about the bond lengths is correct?
In terms of nucleophilicity, which compound is more nucleophilic than the others?
In terms of nucleophilicity, which compound is more nucleophilic than the others?
Which of the following is a correct representation of a sulfoxide?
Which of the following is a correct representation of a sulfoxide?
What type of reaction occurs to prepare thiol from a halogenoalkane?
What type of reaction occurs to prepare thiol from a halogenoalkane?
Which functional group has a higher pKa value than RSH?
Which functional group has a higher pKa value than RSH?
Which compound contains a sulfonium ion?
Which compound contains a sulfonium ion?
What type of electrophilic species does sulfoxide represent?
What type of electrophilic species does sulfoxide represent?
Which process yields R1SH from R1X using Na2S?
Which process yields R1SH from R1X using Na2S?
What type of addition is most associated with sulfoxonium compounds?
What type of addition is most associated with sulfoxonium compounds?
Which of the following represents a stronger nucleophile?
Which of the following represents a stronger nucleophile?
Which reaction is characterized by syn-elimination?
Which reaction is characterized by syn-elimination?
Which compound is characterized as a soft nucleophile?
Which compound is characterized as a soft nucleophile?
What is the outcome of base treatment of sulfoxonium compounds?
What is the outcome of base treatment of sulfoxonium compounds?
Which heterocycle is indicated to have a structure containing sulfur and nitrogen?
Which heterocycle is indicated to have a structure containing sulfur and nitrogen?
What type of compound is selenocysteine classified as?
What type of compound is selenocysteine classified as?
Which oxidation method is properly matched with its product?
Which oxidation method is properly matched with its product?
The stronger nucleophilicity in chalcogenides is generally characterized by which compound comparison?
The stronger nucleophilicity in chalcogenides is generally characterized by which compound comparison?
Which of the following transformations is characterized by instability of selenoxides?
Which of the following transformations is characterized by instability of selenoxides?
What is a common application of diselenides in nucleophilic reactions?
What is a common application of diselenides in nucleophilic reactions?
Which of the following reactions involves selenol as a nucleophile?
Which of the following reactions involves selenol as a nucleophile?
Which selenide species is an electrophilic reactant?
Which selenide species is an electrophilic reactant?
What product is formed after the oxidative treatment of PhSeH with SeO2?
What product is formed after the oxidative treatment of PhSeH with SeO2?
What is the primary biological function of glutathione peroxidase?
What is the primary biological function of glutathione peroxidase?
What type of chemical reaction does palladium-catalyzed cross coupling involve?
What type of chemical reaction does palladium-catalyzed cross coupling involve?
Which functional group is present in glutathion?
Which functional group is present in glutathion?
What type of compounds are boranes classified as?
What type of compounds are boranes classified as?
What does the process of hydride transfer typically involve?
What does the process of hydride transfer typically involve?
Bortezomib is primarily known for its activity in which area?
Bortezomib is primarily known for its activity in which area?
What is the role of selenium in biological systems as mentioned in the context?
What is the role of selenium in biological systems as mentioned in the context?
What is the typical role of a nucleophile in a nucleophilic addition reaction?
What is the typical role of a nucleophile in a nucleophilic addition reaction?
Which of the following represents a common reactant in the Suzuki-Miyaura coupling?
Which of the following represents a common reactant in the Suzuki-Miyaura coupling?
Which sulfur compound is mentioned in the context as part of the chemical reactions shown?
Which sulfur compound is mentioned in the context as part of the chemical reactions shown?
Which of the following drugs is known as an antiviral agent?
Which of the following drugs is known as an antiviral agent?
What is the primary role of DAST in fluorination processes?
What is the primary role of DAST in fluorination processes?
Which factor helps manage the fluorine ion's stabilization in water?
Which factor helps manage the fluorine ion's stabilization in water?
Which method is employed for nucleophilic fluorination according to the content?
Which method is employed for nucleophilic fluorination according to the content?
What type of drug is Celecoxib known for?
What type of drug is Celecoxib known for?
Which characteristic is noted for sulfonyl fluorides in fluorination reactions?
Which characteristic is noted for sulfonyl fluorides in fluorination reactions?
Selectfluor is primarily used for which fluorination type?
Selectfluor is primarily used for which fluorination type?
What is the role of thermodynamic stability in fluorinated compounds?
What is the role of thermodynamic stability in fluorinated compounds?
Which of the following describes a characteristic of fluorouracil?
Which of the following describes a characteristic of fluorouracil?
What type of reaction is described by SuFEx?
What type of reaction is described by SuFEx?
Study Notes
Sulfur Chemistry
- Sulfur is a chalcogenide, meaning it is part of group 16 on the periodic table.
- Key sulfur containing molecules include cysteine, taurine, sulfanilamide, penicillin, and omeprazole.
- Sulfur atoms are more electronegative than carbon atoms, meaning they attract electrons more strongly.
- The C-S bond is 1.81 å.
- The S-S bond is 2.05 å.
- Thiol (R-SH) is more acidic than an alcohol (pKa of 10 vs. 16) and has a stronger acidity than phenol (pKa of 8 for PhSH versus 9.9 for PhOH).
- Thiolate (RS-) is a stronger nucleophile than phenolate (PhONa) and alkoxides (RONa).
- Sulfoxide (R=S=O) and sulfone (R=SO2=R) are more stable than selinoxide (R=Se=O) and selinone (R=SeO2=R).
S-Heterocycle
- Thiophene is a five-membered, sulfur-containing heterocycle.
- Thiazole, benzothiazole, and imidazothiazole are other examples of sulfur containing heterocycles.
Selenium Chemistry
- Selenium is a chalcogenide.
- Selenium is less electronegative than oxygen and sulfur.
- Selenium bonds are longer than sulfur bonds.
- Selenoxides (R=Se=O) are more reactive than sulfoxides (R=S=O) and are easily generated from selenol (R-SeH).
- Selenium can undergo rapid oxidation.
- Organoselenium compounds are often biologically active, serving as antioxidants and anti-inflammatory agents.
- Key selenium containing molecules include ebselen and selenocysteine.
Bore Chemistry
- Boron has a valence of 3 electrons and its NMR signal is at 11 ppm.
- Key boranes are BH3 and BR3.
- Key boron containing molecules include boric acids (B(OH)3 ), boronic acids (R-B(OH)2), boronic esters (R-B (OR')2), and bortezomab (anticancer agent).
- Boric acid is a weak acid.
- Boron can be incorporated using palladium catalyzed Suzuki-Miyaura coupling.
Reactivity and Synthesis
- Boron undergoes nucleophilic addition, hydride transfer, and alkyl transfer reactions.
- Organoboron undergo reduction of alkenes and alkynes via hydroboration reactions.
- Boranes can be oxidized to form alcohols, aldehydes, and ketones.
- Boranes are useful for carbon-carbon bond formation via Suzuki-Miyaura coupling.
- Boranes can be used to synthesize prodrugs.
- Boranes are biologically active due to their ability to modulate enzyme activity.
Fluorination
- In drug development, fluorination is used to modulate certain properties
- Permeability is improved through hydrophoby
- pKa is influenced by its electronegativity which affects potency
- Fluorine is a hydroxyle/hydrogen isostere
- Fluorine is used for positron emission tomography (PET) with 18F
Known Fluorinated Drugs
- Fluorouracil is an anticancer drug
- Celecoxib is an anti-inflammatory drug
- Trifluridine is an antiviral drug
Nucleophilic Fluorination
- Diethylaminosulfur trifluoride (DAST) is used for deoxyfluorination
- DAST reacts with an alcohol to form a fluoride
Electrophilic Fluorination
- Selectfluor is an electrophilic fluorinating reagent
- Selectfluor reacts with a nucleophile to form a fluoride
SuFEx: Sulfonyl Fluorides (RSO2F)
- Sulfonyl fluorides are used in a new Click reaction
- Advantages:
- Ease of preparation
- High stability in water, even under acidic or basic conditions
- High reactivity with various C, N and O-nucleophiles
- Thermodynamic stability
- Fluoride-proton interaction: Stabilizes the fluoride ion in water, allowing for chemistry in aqueous environments.
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Description
Explore the fascinating chemistry of sulfur and selenium, including their properties, key molecules, and unique bonding characteristics. This quiz covers essential concepts such as acidities of thiols, stability of sulfoxides, and various sulfur-containing heterocycles. Test your knowledge of these important chalcogenides and their applications in biochemistry.
