SMIRKS Reactions

SMIRKS Reactions

ADMET Predictor supports the SMIRKS reaction language developed by Daylight CIS, Inc. That company’s website (www.daylight.com) provides an excellent tutorial for the SMIRKS language, so details of the syntax will not be provided here. Note that ADMET Predictor’s enhancements to the SMARTS query language are also incorporated into the SMIRKS engine; see the Query Formats section for complete details.

Note also that any limitations in ADMET Predictor’s support of SMARTS queries also affect SMIRKS support. The most significant example is the SMARTS “wildcard” atom query, denoted by an asterisk (*). The Daylight interpretation of this symbol is “any atom, including Hydrogen.” By contrast, ADMET Predictor interprets the * symbol as “any atom, excluding Hydrogen.” This distinction can have a dramatic effect on how SMIRKS strings are processed during reactions.

Examples of SMIRKS reactions include:

Replacement of oxygen by sulfur:

[O:1]>>[S:1]

Amide formation:

[C:1](=[O:2])[OH].[NH2:3][C:4]>>[C:1](=[O:2])[NH:3][C:4]