Principal Scientist I, Medicinal Chemistry

Mariana Oncology•Watertown, MA

11h

About The Position

Mariana Oncology is seeking a Principal Scientist I, Medicinal Chemistry to join our Discovery Chemistry team. The successful candidate will play a key role in advancing innovative radiopharmaceutical and precision medicine programs, with a focus on peptide-based therapeutics. This individual will contribute both as a technical and strategic leader to medicinal chemistry efforts from hit identification through candidate nomination.

Requirements

PhD in Organic Chemistry, Medicinal Chemistry, or a related discipline with 0-3 years of relevant industry experience; or BS/MS in Chemistry or a related discipline with 6+ years of relevant industry experience.
Demonstrated expertise in peptide medicinal chemistry and peptide synthesis is required.
Strong understanding of drug discovery principles, medicinal chemistry, structure-based drug design, and synthetic organic chemistry.
Proven ability to independently solve complex scientific challenges and develop creative, practical solutions.
Experience managing external CROs and scientific collaborations.
Demonstrated ability to influence project direction, build productive cross-functional relationships, and thrive in a collaborative, matrixed environment.
Excellent communication, organizational, and scientific writing skills with strong attention to detail.

Nice To Haves

Experience in small-molecule medicinal chemistry is a plus.

Responsibilities

Lead medicinal chemistry design and synthesis activities from hit identification through lead optimization and candidate selection.
Serve as a hands-on contributor, executing multi-step peptide syntheses to support radiopharmaceutical discovery programs.
Provide scientific leadership and operational oversight for peptide synthesis laboratory activities.
Serve as an internal subject matter expert in peptide chemistry, driving problem-solving efforts, improving workflows, and advising project teams on synthetic strategy.
Mentor and provide technical guidance to junior scientists, co-ops, and interns.
Manage external CRO relationships to ensure timely execution of chemistry objectives.
Collaborate with cross-functional teams, including biology, radiochemistry, DMPK, and pharmacology, to advance discovery programs.
Derive insights from chemistry, affinity, pharmacology, and DMPK datasets to inform molecular design, project strategy, and candidate selection.
Present project updates and scientific findings to project teams, departmental audiences, and leadership through clear oral and written communications.
Maintain accurate electronic laboratory notebook records and ensure compliance with laboratory safety and HSE requirements.
Partner with Development colleagues to transfer synthetic methods and analytical procedures supporting regulatory-enabling studies.
Deliver high-quality results while effectively managing priorities and timelines in a fast-paced environment.