Volume 2 Chapter 2 2D-Constrain Sub-menu MIN-CONNECTIONS

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NO-CYCLIC-ROUTES

Function

NO-CYCLIC-ROUTES is used to constrain the fragment such that:

either one or more specified atoms can not be connected by cyclic bonds to any atoms outside the fragment

or none of the atoms of the fragment can be connected by cyclic bonds to any atoms outside the fragment.

Examples

Ex. 1 Suppose we have built the fragment (i) - see below - and suppose we wish to constrain the fragment to have no cyclic route at atom a.

A search conducted with fragment (ii) would register hits for (iii) - (vi) but not for (vii).

Ex. 2 Suppose we have built the fragment (i) and suppose we wish to constrain the fragment to have no cyclic routes at any of the atoms of the fragment.

A search conducted with this fragment would register hits for (iii) - (v)

but not for (vi) , (vii).

Ex. 3 This simply illustrates how to change a NO-CYCLIC-ROUTES specification.

Suppose we have constructed the fragment:

(a) If we now wish to remove the constraint on the N atom, with the NO-CYCLIC-ROUTES command active:

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Volume 2 Chapter 2 2D-Constrain Sub-menu NO-LINKS.