URSA Building Blocks (URSA-BBs)

A catalog of commercially available building blocks used as the starting-material stock (stock-termination reference) in the URSA retrosynthesis benchmark. A predicted route is considered stock-terminated when all of its terminal leaves are present in this set. This is a plain list of structures and identifiers — no prices, vendors, or availability metadata are redistributed.

Dataset structure

A single CSV file with two columns:

column	description
bb_id	URSA internal identifier, e.g. URSA-BB-000000
smiles	SMILES of the building block

• Rows: 255,958
• Format: UTF-8 CSV, comma-separated, header row.
• Identifiers are URSA-internal and carry no external meaning.

Usage

from datasets import load_dataset
ds = load_dataset(
    "insilicomedicine/URSA-BBs",
    data_files="URSA_BBs_v1_0_0.csv",
)

Source and provenance

The structure selection is derived from the ASKCOS "buyables" catalog, with commercial availability independently verified against eMolecules. The original ASKCOS identifiers were not retained; every entry was reassigned a fresh URSA-internal bb_id. No eMolecules catalog data is redistributed — eMolecules was used only to confirm purchasability.

License

This dataset is released under CC BY-NC-SA 4.0.

Citation

If you use this dataset, please cite the URSA paper:

@misc{zagribelnyy2026ursachemistryawarebenchmarkutilitarian,
  title={URSA: Chemistry-Aware Benchmark for Utilitarian Retrosynthesis Assessment}, 
  author={Bogdan Zagribelnyy and Ivan Ilin and Nikita Bondarev and Anton Morgunov
          and Arkadii Lin and Maksim Kuznetsov and Rim Shayakhmetov
          and Vladimir Aladinskiy and Alex Aliper and Alex Zhavoronkov},
  year={2026},
  eprint={2607.04688},
  archivePrefix={arXiv},
  primaryClass={cs.LG},
  url={https://arxiv.org/abs/2607.04688}, 
}