Director, Antiviral Medicinal Chemistry

Assembly Biosciences, Inc.; South San Francisco (CA); Hybrid; USD 220,000 - 234,000; Full time

Job summary

Assembly Biosciences, Inc. in South San Francisco is seeking a Director of Medicinal Chemistry to co-lead a full-phase antiviral discovery program, guiding design, synthesis, and testing from lead optimization to candidate nomination.

The role involves cross-functional collaboration across virology, DMPK, and informatics to optimize exposures and safety margins. Ideal candidates hold a PhD in chemistry with 8+ years in drug discovery, demonstrated leadership in discovery programs, and strong

Qualifications

• PhD in synthetic organic or medicinal chemistry is required.
• Minimum 8 years in drug discovery in pharma/biotech.
• Experience leading or co-leading a discovery program from hit-to-lead to nomination.
• Creative drug design and problem solving skills.
• Knowledge of PK/PD concepts and applying them to design.

Responsibilities

• Co-lead a full-phase small molecule discovery program; drive design–synthesis–test–analysis cycles.
• Design target molecules and chemical series; apply SAR in collaboration with computational chemistry teams.
• Direct CRO partners; set priorities, review routes, ensure data quality and timelines.
• Integrate virology, biochemistry, DMPK, and safety data into design; address liabilities.
• Mentor colleagues and CRO scientists; contribute to a collaborative scientific culture.
• Present updates to project teams, R&D leadership, and external partners.
• Review patent literature and assist in invention disclosures and filings.

Skills

Excellent written and oral comms

Strong interpersonal skills

Team collaboration

Data-driven decision making

Mentoring and coaching

Education

PhD in synthetic organic or medicinal chemistry

Tools

Computational chemistry tools

Job description

Assembly Biosciences, Inc. in South San Francisco is seeking a Director of Medicinal Chemistry to co-lead a full-phase antiviral discovery program, guiding design, synthesis, and testing from lead optimization to candidate nomination.

The role involves cross-functional collaboration across virology, DMPK, and informatics to optimize exposures and safety margins. Ideal candidates hold a PhD in chemistry with 8+ years in drug discovery, demonstrated leadership in discovery programs, and strong