lightningspeed
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Why should 2-methylbutan-3-ol be 3-methylbutan-2-ol?
same thing for: 3-methyl-2-bromobutane should be 2-bromo-3-methylbutane?
Last edited by lightningspeed; 8 months ago
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lightningspeed
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help
(Original post by lightningspeed)
Why should 2-methylbutan-3-ol be 3-methylbutan-2-ol?
They are the same molecule?
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sotor
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don't bump your threads after one minute OP, give us a chance to answer

for 3-methylbutan-2-ol, the alcohol group takes priority therefore the carbon is it on should be the lowest number i.e. the closest to the first carbon in the chain.

(i don't know for the second one sorry)
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lightningspeed
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the second one is because IUPAC naming is in order of alphabets so b before m.
Is it always the case that the heavier group should be closer to first carbon because I have never heard of that rule?
(Original post by sotor)
don't bump your threads after one minute OP, give us a chance to answer

for 3-methylbutan-2-ol, the alcohol group takes priority therefore the carbon is it on should be the lowest number i.e. the closest to the first carbon in the chain.

(i don't know for the second one sorry)
Last edited by lightningspeed; 8 months ago
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David Tan
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(Original post by lightningspeed)
Why should 2-methylbutan-3-ol be 3-methylbutan-2-ol?
same thing for: 3-methyl-2-bromobutane should be 2-bromo-3-methylbutane?
When it comes to applying the IUPAC rules to the naming of organic species, certain functional groups are given greater priorities over others. For example, if an organic molecule contains a carboxyl group and an alkene group, the carboxyl group is given a greater priority and the C atom in the carboxyl group must be given a smaller number.

Why should 2-methylbutan-3-ol be 3-methylbutan-2-ol?
Answer: The hydroxyl group has a greater priority over the alkyl group. Hence, the C atom that is directly connected to the -OH group must be given a smaller number.

same thing for: 3-methyl-2-bromobutane should be 2-bromo-3-methylbutane?
Answer: Bromo starts with letter 'B'. Methyl starts with letter 'M'. In the alphabetical series, 'B' comes before 'M'. This species contains an alkyl halide group and an alkyl group. Priority is given to the alkyl halide group and hence, the C atom that is directly connected to the halogen must be given a smaller number.
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lightningspeed
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Cool
Is the heavier group always given the priority?
(Original post by David Tan)
When it comes to applying the IUPAC rules to the naming of organic species, certain functional groups are given greater priorities over others. For example, if an organic molecule contains a carboxyl group and an alkene group, the carboxyl group is given a greater priority and the C atom in the carboxyl group must be given a smaller number.

Why should 2-methylbutan-3-ol be 3-methylbutan-2-ol?
Answer: The hydroxyl group has a greater priority over the alkyl group. Hence, the C atom that is directly connected to the -OH group must be given a smaller number.

same thing for: 3-methyl-2-bromobutane should be 2-bromo-3-methylbutane?
Answer: Bromo starts with letter 'B'. Methyl starts with letter 'M'. In the alphabetical series, 'B' comes before 'M'. This species contains an alkyl halide group and an alkyl group. Priority is given to the alkyl halide group and hence, the C atom that is directly connected to the halogen must be given a smaller number.
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David Tan
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(Original post by lightningspeed)
Cool
Is the heavier group always given the priority?
Nope, it doesn't work that way. There is a set of rules in the book of IUPAC.
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lightningspeed
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lol ok
(Original post by David Tan)
Nope, it doesn't work that way. There is a set of rules in the book of IUPAC.
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