Lowest-locant numbering
What Lowest-locant numbering means in Chemistry A-Level, as defined for OCR.
Definitions of Lowest-locant numbering
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Reference: OCR
Numbering the ring so substituents receive the lowest possible locants, with the principal functional group taking priority for numbering.
Numbering the chain so the principal group, or the first point of difference, gets the lowest possible locant.
Topics that use Lowest-locant numbering
- Aromatic compounds (OCR A-Level)
- Basic concepts of organic chemistry (OCR A-Level)
Related terms
- Activating and 2,4-directing effect of the –OH group
- Alphabetical ordering of substituents
- Aromatic compound
- Bond lengths in benzene
- Carbon–carbon bond formation in synthesis
- carboxyl group
- Characteristic reactions
- Comparison with carboxylic acids and the carbonate test
Using Lowest-locant numbering in the exam
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