Isomerism of the general form:
where the isomers (called tautomers) are readily interconvertible; the atoms connecting
the groups X, Y, Z are typically any of
C,
H,
O or
S, and G is a group which becomes an
electrofuge or
nucleofuge during
isomerization. The commonest case, when the
electrofuge is
H+, is also known as '
prototropy'. Examples, written so as to illustrate the general pattern given above, include:
Keto-enol tautomerism, such as:
The grouping Y may itself be a three-atom (or five-atom) chain extending the
conjugation, as in:
The double bond between Y and Z may be replaced by a ring, when the phenomenon is
called ring-chain tautomerism, as in:
Source:
PAC, 1994, 66, 1077
(Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994))
on page 1171
InChI=1/C5H5NO/c7-5-1-3-6-4-2-5/h1-4H,(H,6,7)/f/h7H
InChI=1/C5H5NO/c7-5-1-3-6-4-2-5/h1-4H,(H,6,7)/f/h6H
InChI=1/C8H12O5/c1-4-5(9)13-8(12,6(10)11)7(4,2)3/h4,12H,1-3H3,(H,10,11)/f/h10H
InChI=1/C8H12O5/c1-4(6(10)11)8(2,3)5(9)7(12)13/h4H,1-3H3,(H,10,11)(H,12,13)/f/h10,12H
InChI=1/C9H14O4/c1-5-6(10)13-9(4,7(11)12)8(5,2)3/h5H,1-4H3,(H,11,12)/f/h11H
InChI=1/C6H10O3/c1-3-9-6(8)4-5(2)7/h4,7H,3H2,1-2H3/b5-4+
InChI=1/C6H10O3/c1-3-9-6(8)4-5(2)7/h3-4H2,1-2H3
GCNTZFIIOFTKIY-QDQILVOLCT
GCNTZFIIOFTKIY-BRMMOCHJCN
XCVUQMYEBSBXPN-KZFATGLACO
QOGCXTXBWCCNTB-QIQUEDJNCN
AUFHUNBTRGWGCF-WXRBYKJCCI
ROBJRQHNPKJRFH-SNAWJCMRBC
XYIBRDXRRQCHLP-UHFFFAOYAP
