McMurry (13,7-13,8) - Preperation and reactions of thiols + ethers and sulfides Flashcards
What is the most striking characteristic of thiols?
Their appalling odor, skunk scent, primarily caused by the 3-methylbutane-1-thiol and but-2-ene-1-thiol.
How are thiols prepared?
From alkyl halides by SN2 displacement with a sulfur nucleophile such as hydrosulfide anion (SH).
The Br already existing in the alkyl halide is switched with the sulfur.
(the reaction works poorly unless an excess of the nucleophile (SH) is used - because the product thiol can undergo a second SN2 reaction with alkyl halide to give sulfide as a byproduct. (to prevent this problem (NH2)2C=S is used as the nucleophile in the preperation of thiol from an alkyl halide. (see page 463 for example of the reaction).
Can thiols be oxidized?
Yes, by Br2 and I2 to yield disulfides (RSSR).
The reaction is reversed by treatment with zink and acid.
The thiol - disulfide interconversion is a key part of numerous biological processes.
which for example?
Involved in defining the structure and 3D conformation of proteins
Disulfide formation is also involved in the process by which cells protect themselves from oxadative degeneration. (page 464 more detailed).
How is ether named?
By identifying the two organic functional groups attached to either side of the ether, and named adding the word ether lastly.
(ethyl phenyl ether) - page 464.
Ethers considered an alkoxy substituent If an ether is not the highest-priority functional group in the molecule, it is named as an alkoxy substituent (butoxy (4 c attached to O).
How are sulfides named?
The same rules as for ethers:
-sulfide used instead of ether.
-alkylthio used in more complex substances.
Does ethers have the same geometry as water?
Yes, R-O-R bond that is nearly tehtrahedral (112 grader) in demethyl ether, and the O is sp3 hybridized.
