(Senior / Principal) Scientist, Medicinal Chemistry

We are a vibrant and intensely mission-driven team in San Francisco, comprising members from MIT, Harvard Medical School, Roche, ETH, and Dana-Farber. We value speed and rigor, coupled with excitement, drive, and a strong work ethic. In an early-stage environment, we value people who can bring clarity to open-ended problems, take ownership of the next steps, and follow through with energy. Capable Labs is a place for ambitious, high-integrity people who want to become dramatically better. You will be surrounded by people who care intensely about the work, get close feedback from the people making scientific and company-defining decisions, and have room to own increasingly important problems. We believe excellent work should be met with meaningful reward, ownership, and trust. Responsibility is earned through contribution, not title alone: anyone who demonstrates the judgment, rigor, and follow-through to move important work forward can earn meaningful scope. About the Role You will lead medicinal-chemistry design and synthesis across Capable’s therapeutic programs, deciding which compounds to make and translating SAR and biological data into the next design cycle. You will remain hands-on from route selection through purification and characterization while owning the chemistry decisions that improve potency, selectivity, stability, exposure, tolerability, and efficacy. Responsibilities Lead compound design and synthesis across small-molecule, peptide, and peptide-adjacent programs, from target-compound selection through biological handoff. Use SAR, in vitro, and in vivo data to prioritize and design next-round compounds. Design and execute practical synthetic routes using solution-phase or solid-phase workflows, functional-group transformations, coupling chemistry, protecting groups, and late-stage diversification as appropriate. Own synthesis, purification, characterization, quality control, documentation, and preparation of compounds for biological testing. Operate and help maintain key chemistry instrumentation, including HPLC, prep HPLC, LC-MS, microwave-assisted synthesis systems, and related analytical or purification platforms. Resolve difficult synthetic and analytical issues involving failed reactions, selectivity, side products, solubility, purification, recovery, or instrument performance. Partner closely with biology and pharmacology teams to connect chemistry decisions to potency, selectivity, stability, exposure, tolerability, and efficacy. Ideal Qualifications Five or more years of hands-on industry experience in medicinal or synthetic organic chemistry; peptide experience is helpful but not required. Strong medicinal-chemistry judgment and the ability to use SAR and biological data to decide what to make next. Experience owning chemistry end to end, including compound design, route selection, synthesis, purification, characterization, quality control, and biological handoff. Deep troubleshooting ability and a high bar for clean experimental execution and documentation. Comfort working close to biological readouts and balancing potency, selectivity, stability, exposure, tolerability, efficacy, and practical synthesis. The ability to provide technical direction and raise the quality of a program while remaining hands-on. Pay & Benefits In addition to the posted salary range, we offer generous equity options. Compensation will depend on the skills, experience, and scope of impact you bring. If your background, experience, or compensation needs fall outside this range, we are still open to a conversation based on the scope and impact you could bring. $500+ monthly wellness budget for training, supplements, coaching, recovery, or other tools that help you perform at your best. Healthcare: We offer a broad range of medical, dental, and vision coverage options, with Capable covering 100% of the base policy. You will also have access to HSA, FSA, and 401K plans. Healthy dinners with the team are provided daily. We support visa sponsorship where appropriate, including O-1, H-1B, J-1, TN, and other employment-based pathways. Our team is already international, with members from Canada, Pakistan, Germany, Austria, Switzerland, China, India, and the United States. Application Process Our process is fast, transparent, and personal. We care about getting to know the person behind the application. Initial application First phone screen Second phone screen In-person work trial in San Francisco: designed to give both sides a realistic sense of working together. Get to know the founding team! Apply Today Curious but not sure? Apply anyway. It takes 5 minutes, and you do not need to be actively job searching to start a conversation. Some of the best people do not map perfectly to a job description. If this sounds like a place where you could do important work, we would like to hear from you. And if someone exceptional comes to mind, send them our way here. We read every referral carefully, and if your referral joins Capable, we’ll send you a thank-you bonus. Equal Opportunity Capable is an Equal Opportunity Employer; employment with Capable is governed on the basis of merit, competence and qualifications and will not be influenced in any manner by race, color, religion, gender, national origin/ethnicity, veteran status, disability status, age, sexual orientation, gender identity, marital status, mental or physical disability or any other legally protected status.