rhoahndur/retrosynthesis-qwen3-4b
TEXT GENERATIONConcurrency Cost:1Model Size:4BQuant:BF16Ctx Length:32kPublished:Mar 24, 2026License:apache-2.0Architecture:Transformer Open Weights Cold

The rhoahndur/retrosynthesis-qwen3-4b model is a Qwen3-4B fine-tuned for retrosynthetic route prediction. Developed by rhoahndur, this model specializes in predicting reactant molecules from a given target molecule SMILES. It was trained using GRPO with a 6-component RDKit reward rubric on the USPTO-50K dataset, making it highly effective for chemical synthesis planning.

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Overview

The rhoahndur/retrosynthesis-qwen3-4b model is a specialized Qwen3-4B variant developed by rhoahndur, specifically fine-tuned for retrosynthetic route prediction. Its primary function is to take a target molecule's SMILES string and predict the reactant molecules required to synthesize it.

Key Capabilities

  • Retrosynthesis Prediction: Accurately predicts reactant SMILES given a target molecule SMILES.
  • GRPO Training: Utilizes Guided Reinforcement Policy Optimization (GRPO) for training, incorporating a sophisticated 6-component RDKit reward rubric.
  • Robust Reward System: The reward rubric includes validity, synthetic accessibility (SA) score, stock match, and atom conservation, ensuring chemically sound predictions.
  • Specialized Dataset: Trained on the USPTO-50K dataset, specifically using the rhoahndur/retrosyn-targets subset, which focuses on chemical reactions.

Good For

  • Chemical Synthesis Planning: Ideal for researchers and chemists needing to identify potential precursor molecules for a desired target compound.
  • Drug Discovery: Can assist in the early stages of drug development by suggesting synthetic pathways for novel compounds.
  • Educational Tools: Useful for demonstrating and exploring retrosynthetic analysis concepts.

This model differentiates itself by its highly specialized fine-tuning for a critical task in chemistry, offering a focused solution for predicting chemical reactions rather than general language tasks.