Only in simple synthesis problems one can expect that a search for suitable
starting materials already succeeds with the target compound. In most cases,
the synthesis problem has to be simplified by first generating synthesis precursors.
Therefore, methods for the search and evaluation of strategic bonds have
been implemented in WODCA whereby the application of a classical synthon-
or transform-oriented knowledge base has been avoided.
For each bond, the two possible heterolytic bond breakings are explored
and evaluated by physicochemical effects such as bond polarity
[1], and the stabilization of charges by inductive [2]
, resonance [3], and polarizability effects
[4]. These methods are calculated by rapid procedures collected in the
PETRA system [5]. Furthermore, structural effects such
as points of bond branching of bonds, positions at ring systems, and stereochemical
centers are taken into account. Four different groups of disconnection strategies
have been implemented working on the basis of these parameters
- carbon-heteroatom
bonds
- aliphatic bonds
- aromatic substitution
- polycyclic
compounds
References:
[1]
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J. Gasteiger, M. Marsili, Tetrahedron 1980, 36, 3219-3228
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[2]
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M. G. Hutchings, J. Gasteiger, Tetrahedron Lett. 1983,
24, 2541-2544.
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[3]
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J. Gasteiger, H. Saller, Angew. Chem. 1985, 97, 699-701;
Angew. Chem. Int. Ed. Engl. 1985, 24
, 687-689.
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[4]
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J. Gasteiger, M. G. Hutchings, J. Chem. Soc. Perkin 2 1984,
559-564.
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[5]
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J. Gasteiger, Empirical Methods for the Calculating of Physicochemical Data
of Organic Compounds, Physical Property Prediction in Organic Chemistry,
C. Jochum, J. Hicks, J. Sunkel (Eds.), Springer Verlag, Heidelberg, 1988,
119-138.
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