Improvements to version 4.52:
- Some atom map operations 2X faster.
- Transformation operations 10-20% faster.
- Bug fixes:
Copies of reaction patterns and transformations invalid.
Labels for reaction depictions fail.
Part n-tuples fail for molecules with explicit hydrogens. Common
with atom-mapped reactions.
Now link multi-step reactions.
CCR contains 288,500 reactions (268,000 SMILES), 95,500 are reported
as single-steps, 146,800 are part of 46,300 multi-step sequences.
New update: 1996 data.