Fractional Head of Chemistry (Bioinorganics)

Fractional Head of Chemistry (Bioinorganic Therapeutics)
Location: San Francisco Bay Area (Hybrid / Remote-Flexible)
Role Type: Scientific Advisory (Phase 1) → Fractional Head of Chemistry (Phase 2)
Domain: Targeted Therapeutics | Heterobifunctional Conjugates | Bioinorganic Chemistry
About the Venture
We are a biotechnology startup based in the San Francisco Bay Area developing bioinorganic conjugates engineered to selectively inactivate our targets for treating aging-related diseases.
Our founding team brings deep expertise in molecular biology, translational medicine, and early-stage company building. We are seeking a Fractional Head of Chemistry to serve as our founding team member. This individual will bridge novel conjugate design, bioinorganic coordination chemistry, and hands-on synthetic execution across global contract research organizations (CROs).
Progression Structure
Our lean pre-seed strategy relies heavily on CROs for our operations. Because we expect a part time appointment will be sufficient for managing these external programs, we are structuring this partnership in two phases:
Phase 1 (Pre-Funding - Strategic Advisor): Upon a successful mutual fit, we will onboard you immediately under an Advisor Agreement. In this phase, your commitment will be minimal (3-5 hours/month), focused on strategy reviews and high-level workflow alignment as we prepare for investor pitches. You will receive competitive equity for this role.
Phase 2 (Post-Funding - Fractional Head of Chemistry): Immediately upon the closing of our pre-seed round, the Advisor Agreement will terminate, and you will transition to the Fractional Head of Chemistry role (averaging 20 hours/week) for approximately one year. This phase will focus on active CRO management, IP generation, and establishing a strong working relationship, with the long-term goal of exploring a full-time transition as we scale.
Key Responsibilities
1. Conjugate Architecture and Medicinal Chemistry Strategy
Direct the Design-Make-Test-Analyze (DMTA) cycle for novel heterobifunctional conjugates integrating homing moieties, linkers, and specialized coordination ligands.
Establish Structure-Activity Relationships (SAR) and Structure-Property Relationships (SPR) balancing target binding affinity, linker integrity, and complex stability.
Drive multi-parameter optimization (MPO) for parenteral (IV/SC) administration, mitigating liabilities such as non-specific systemic reactivity, transchelation/metal stripping by serum proteins, metabolic cleavage, and self-aggregation.
2. CRO Operations
Architect and oversee an outsourced synthetic chemistry footprint across premier global CROs.
Direct multi-step organic synthesis of complex ligands, bioconjugation steps, metallation protocols, and the handling/purification of polar, charged, or zwitterionic molecular entities.
Review raw analytical data (NMR, HRMS, LC-MS, ICP-MS) and troubleshoot synthetic bottlenecks, protecting-group compatibilities, and challenging purification profiles (preparative RP-HPLC, ion exchange).
Establish rigorous quality control standards for conjugate purity, identity, counter-ion control, and speciation stability.
3. IP and Commercial Leadership
Partner with the CEO and premier patent counsel to evaluate and expand our Invention Disclosure Forms (IDFs), ensuring robust synthetic enablement, defensible Markush structures, and long-term Freedom to Operate (FTO).
Act as the chemical design authority in investor meetings, partnering discussions, and Scientific Advisory Board (SAB) presentations.
Required Qualifications (Must-Have)
Education: Ph.D. in Synthetic Organic Chemistry, Bioinorganic Chemistry, Medicinal Chemistry, or a closely related discipline.
Domain Track Record: 4+ years of biotech or pharmaceutical industry experience working with metal-chelating small molecules or conjugates (e.g., heterobifunctional molecules, radiopharmaceuticals/theranostics, bifunctional chelators [BFCs], or metallodrugs).
Bioinorganic Fluency: Strong practical understanding of metal chelation and coordination chemistry, including ligand field dynamics, metal complexation kinetics, thermodynamic stability vs. kinetic inertness, and serum stability challenges.
CRO Management: Proven track record of architecting, contracting, and driving synthetic chemistry CROs through challenging multi-step organic syntheses, route scouting, and compound delivery.
IP Cleanliness: Fully unencumbered by restrictive IP assignments, non-competes, or institutional conflicts of interest at the start of Phase 2 (paid executive role).
Preferred Qualifications
Hands-on familiarity with biophysical and analytical methods used to study metal-ligand speciation and coordination stability in biological matrices (e.g., ICP-MS, LC-MS, spectroscopic assays).
Practical experience formulating and optimizing conjugate solubility and stability for parenteral (IV/SC) delivery.
Startup agility: Prior experience as a founder, consultant, or early scientific employee in a seed- or Series A–stage virtual biotech.
IP cleanliness unencumbered starting in Phase 1 (Advisory).
What We Offer
Founding Equity: Substantial early-stage equity grant reflecting founding-tier contribution, transitioning to competitive cash + equity upon closing financing.
Scientific Ownership: Complete technical leadership over a brand-new therapeutic modality targeting critical unmet medical needs.
Leadership Opportunity: The potential to help shape our long-term chemistry strategy and explore a permanent executive role as company operations and pipeline programs expand.
How to Apply
Please submit your CV along with a brief cover letter (under 300 words) summarizing the items below. If there is no field available on the application for the cover letter, please merge your cover letter with your CV.
Your experience managing multi-step organic synthesis and conjugate assembly at external CROs.
Your background with metal-coordinating ligands, heterobifunctional conjugates, radiopharmaceuticals, or bioinorganic chemistry.
Confirmation of your IP cleanliness / freedom to advise.

Work arrangement
Yes