Bicyclic molecule

Bicyclic molecule

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bicyclic molecule contains two fused aliphatic rings. Fusion can occur in three ways:
#At two mutually bonded atoms or
#Across a sequence of atoms (bridgehead) - an example is norbornane, bicyclo [2.2.1] heptane - or
#At a single atom (spirocyclic, forming a spiro compound)All these systems occur in naturally-occurring organic compounds, in about the order of commonness of the list above.

Bicyclic molecules have a strict nomenclature. [ [http://www.acdlabs.com/iupac/nomenclature/79/r79_163.htm IUPAC nomenclature for bicyclics] ] On its simplest level the parent hydrocarbon is the equivalent open carbon alkane. For bridged compounds, the prefix "bicyclo" is added, followed by, between brackets and in descending order, the number of carbon atoms in each of the rings not counting the bridgeheads. For example in bicyclo [2,2,1] heptane the carbon frame contains a total of 7 atoms hence the parent name heptane. This molecule has three bridges having 2, 2 and 1 carbon atoms hence the prefix bicyclo [2,2,1] . For spiro compounds, terms like spiro [2,4] are used, indicating that there are 3- and 5-membered rings (because the spiro atom itself is not counted) meeting at the spiro atom.

A bridge is an unbranched chain of atoms or an atom or a covalent bond connecting two bridgeheads in a polycyclic compound.

The "main bridge" is a bridge which connects the two main bridgeheads.

A "secondary bridge" is any bridge not included in the main ring or the main bridge.

An "independent secondary bridge" links bridgeheads which are part of the main ring or main bridge.

A "dependent secondary bridge" links at least one bridgehead which is part of a secondary bridge.

References


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  • bicyclic — [bī sīk′lik] adj. 1. of or forming two cycles 2. Chem. containing only two fused rings in the molecule: Also bicyclical …   English World dictionary

  • bicyclic — 1. adjective a) Having two cycles. b) Having two rings of atoms in the molecule; the rings may be fused, as in naphthalene, or separate, as in …   Wiktionary

  • bicyclic — adjective Etymology: International Scientific Vocabulary Date: circa 1909 1. consisting of or arranged in two cycles 2. containing two usually fused rings in the structure of the molecule …   New Collegiate Dictionary

  • bicyclic — bi·cy·clic ( )bī sī klik, sik lik adj containing two usu. fused rings in the structure of the molecule …   Medical dictionary

  • bicyclic — adj. with two circles or rings; (Chemistry) having two rings of atoms (describing a molecule); (Botany) comprised of or in two different spiral or circular arrangements of leaves or flowers …   English contemporary dictionary

  • bicyclic — [bʌɪ sʌɪklɪk, sɪk ] adjective Chemistry having two fused rings of atoms in its molecule …   English new terms dictionary

  • bicyclic — bi•cy•clic [[t]baɪˈsaɪ klɪk, ˈsɪk lɪk[/t]] adj. 1) Also, bi•cy′cli•cal. consisting of or having two cycles or circles. 2) chem. containing two rings of atoms in a molecule • Etymology: 1875–80 …   From formal English to slang

  • Bicyclique — Composé bicyclique norbornane ou [2.2.1]heptane …   Wikipédia en Français

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