mCLM: A Modular Chemical Language Model that Generates Functional and Makeable Molecules

Fuente: arXiv
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Main Authors: Edwards, Carl, Han, Chi, Lee, Gawon, Nguyen, Thao, Szymkuć, Sara, Prasad, Chetan Kumar, Jin, Bowen, Han, Jiawei, Diao, Ying, Liu, Ge, Peng, Hao, Grzybowski, Bartosz A., Burke, Martin D., Ji, Heng
Format: Preprint
Published: 2025
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author Edwards, Carl
Han, Chi
Lee, Gawon
Nguyen, Thao
Szymkuć, Sara
Prasad, Chetan Kumar
Jin, Bowen
Han, Jiawei
Diao, Ying
Liu, Ge
Peng, Hao
Grzybowski, Bartosz A.
Burke, Martin D.
Ji, Heng
author_facet Edwards, Carl
Han, Chi
Lee, Gawon
Nguyen, Thao
Szymkuć, Sara
Prasad, Chetan Kumar
Jin, Bowen
Han, Jiawei
Diao, Ying
Liu, Ge
Peng, Hao
Grzybowski, Bartosz A.
Burke, Martin D.
Ji, Heng
contents Despite their ability to understand chemical knowledge, large language models (LLMs) remain limited in their capacity to propose novel molecules with desired functions (e.g., drug-like properties). In addition, the molecules that LLMs propose can often be challenging to make, and are almost never compatible with automated synthesis approaches. To better enable the discovery of functional small molecules, LLMs need to learn a new molecular language that is more effective in predicting properties and inherently synced with automated synthesis technology. Current molecule LLMs are limited by representing molecules based on atoms. In this paper, we argue that just like tokenizing texts into meaning-bearing (sub-)word tokens instead of characters, molecules should be tokenized at the level of functional building blocks, i.e., parts of molecules that bring unique functions and serve as effective building blocks for real-world automated laboratory synthesis. This motivates us to propose mCLM, a modular Chemical-Language Model that comprises a bilingual language model that understands both natural language descriptions of functions and molecular blocks. mCLM front-loads synthesizability considerations while improving the predicted functions of molecules in a principled manner. Experiments on FDA-approved drugs showed that mCLM is capable of significantly improving chemical functions. mCLM, with only 3B parameters, also achieves improvements in synthetic accessibility relative to 7 other leading generative AI methods including GPT-5. When tested on 122 out-of-distribution medicines using only building blocks/tokens that are compatible with automated modular synthesis, mCLM outperforms all baselines in property scores and synthetic accessibility. mCLM can also reason on multiple functions and iteratively self-improve to rescue drug candidates that failed late in clinical trials ("fallen angels").
format Preprint
id arxiv_https___arxiv_org_abs_2505_12565
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle mCLM: A Modular Chemical Language Model that Generates Functional and Makeable Molecules
Edwards, Carl
Han, Chi
Lee, Gawon
Nguyen, Thao
Szymkuć, Sara
Prasad, Chetan Kumar
Jin, Bowen
Han, Jiawei
Diao, Ying
Liu, Ge
Peng, Hao
Grzybowski, Bartosz A.
Burke, Martin D.
Ji, Heng
Artificial Intelligence
Computation and Language
Machine Learning
Quantitative Methods
Despite their ability to understand chemical knowledge, large language models (LLMs) remain limited in their capacity to propose novel molecules with desired functions (e.g., drug-like properties). In addition, the molecules that LLMs propose can often be challenging to make, and are almost never compatible with automated synthesis approaches. To better enable the discovery of functional small molecules, LLMs need to learn a new molecular language that is more effective in predicting properties and inherently synced with automated synthesis technology. Current molecule LLMs are limited by representing molecules based on atoms. In this paper, we argue that just like tokenizing texts into meaning-bearing (sub-)word tokens instead of characters, molecules should be tokenized at the level of functional building blocks, i.e., parts of molecules that bring unique functions and serve as effective building blocks for real-world automated laboratory synthesis. This motivates us to propose mCLM, a modular Chemical-Language Model that comprises a bilingual language model that understands both natural language descriptions of functions and molecular blocks. mCLM front-loads synthesizability considerations while improving the predicted functions of molecules in a principled manner. Experiments on FDA-approved drugs showed that mCLM is capable of significantly improving chemical functions. mCLM, with only 3B parameters, also achieves improvements in synthetic accessibility relative to 7 other leading generative AI methods including GPT-5. When tested on 122 out-of-distribution medicines using only building blocks/tokens that are compatible with automated modular synthesis, mCLM outperforms all baselines in property scores and synthetic accessibility. mCLM can also reason on multiple functions and iteratively self-improve to rescue drug candidates that failed late in clinical trials ("fallen angels").
title mCLM: A Modular Chemical Language Model that Generates Functional and Makeable Molecules
topic Artificial Intelligence
Computation and Language
Machine Learning
Quantitative Methods
url https://arxiv.org/abs/2505.12565