A Reaction SLN allows specifying reactants, products, and conditions of a reaction, including information about atom map, reaction centers, inversion, and retention. In a valid Reaction SLN, any part (reactant, product, condition) can be omitted.
Each Reaction SLN may include several reactants and products, which are separate conventional SLN structures. These SLN structures may have their own attributes/specifications. The reaction, in general may have its own specifications/conditions. This hierarchical structure is similar to well-known "parent-child" SLN/CT structures, which are used to represent a Reaction SLN.
An arrow sign (->) is used to distinguish reactants and products in the SLN.
Reactants
Products
<ReactionConditions>
SLN1<>SLN2<>->
SLN3<>SLN4<>
The arrow sign is the only indicator of the Reaction SLN. The leading attribute holder (<>) is mandatory for parent-child structures, but can be omitted for reactions without conditions. Reactants or products may be omitted, and then the following are valid Reaction SLNs:
SLN1<>SLN2<>->
->SLN3<>SLN4<>
A "+" is used to distinguish reactants and/or products from each other in the SLN. In such cases, a standard parent-child separator (i.e., an attribute holder (<>)) is not mandatory and may be omitted when reactants/products have no attributes. For example: CCOH+CC(=O)OH->CC(=O)OCC
Any conditions of the reaction may be specified using user-defined string attributes and placed in the "parent CT" attribute holder. For example: <AGENTS="HCl, EtOH";TEMPERATURE="150F"> CCOH+CC(=O)OH->CC(=O)OCC
The following can be used in the SLN to specify various Reaction SLN attributes:
RXNID: A CT attribute that specifies the reaction ID.
#number: An atom mapping number attribute for use in specifying the number of reactants.
M: The mapped atom attribute for indicating whether or not an atom is to be mapped.
CC: Indicates what to do with the chirality type of an atom.
RC: A bond attribute used to specify if a bond is a reaction center and what to do at that position.
