Expanded functional-group catalogue

Version 15.2 expands the runtime catalogue from 20 to 63 SMARTS-based rules.

Each rule can now carry:

local chemical role;
orbital interpretation;
reaction families;
electronic substituent effects;
local geometry;
hydrogen-bond behavior;
acid/base behavior;
resonance/delocalization;
biochemical context;
motif-specific notes.

The catalogue intentionally permits overlapping matches. A peptide-like amide, for example, can also match the generic amide rule. The match should therefore be interpreted as layered chemical annotation rather than a mutually exclusive classification.

SMARTS detection is structural pattern recognition, not a reaction predictor. Acid/base state, solvent, conformation, kinetics, accessibility, catalysts and neighboring groups can all alter actual chemistry.