Rule C-61 61.1 - In an unbranched structure not containing a group that can be named as principal group, the longest chain of carbon and hetero atoms
terminating with carbon is chosen and named as though the entire chain were that of an acyclic hydrocarbon. The hetero atoms present within this chain are then named by means of prefixes
"aza-", "oxa-", "thia-", etc., as listed in Table B-I of Rule B-1, in the order stated in Rule B-1.4, with locants to indicate their
positions in the chain. Methods described in Section A are then used for multiplying prefixes and for denoting unsaturation. The chain is numbered from one end to the other, excluding terminal hetero
atoms, according to precedences described in Rule C-62.
See Recommendations'93 R-1.2.2
Examples to Rule C-61.1
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