Synthetic Chemist

The Opportunity

We are seeking a talented and motivated Synthetic Chemist to join our team in Cambridge, UK. You will design and synthesise chemically modified nucleosides and nucleotides, with a particular focus on nucleoside di- and triphosphates, to support the development of next-generation RNA therapeutics. These building blocks underpin our efforts to improve RNA stability, enhance cellular delivery and expand the chemical space of RNA medicines. You will work in a collaborative, interdisciplinary environment alongside chemists, molecular biologists and AI specialists. The ideal candidate is an agile, hands-on scientist with a strong foundation in nucleoside and nucleotide chemistry and excellent chromatographic purification skills. We welcome applications from recent PhD graduates as well as experienced MSc-level chemists.

About ScionxBio

ScionxBio is engineering the next generation of RNA medicines, combining synthetic chemistry and artificial intelligence to create xRNA - a platform for long-acting therapeutics. By expanding RNA beyond nature's four-letter alphabet, we engineer molecules that sustain protein expression for weeks to months rather than days, with the durability that chronic disease demands. With an initial focus on cardiometabolic disease, we are working to turn transient treatments into durable therapies. A spinout from Eleven Therapeutics, we are an international team operating across Cambridge (UK), Tel Aviv, and Cambridge (MA), with our Cambridge (UK) site serving as our largest research and development hub, and we are proud to foster a culture of collaboration, diversity, and scientific excellence.

Key Responsibilities

- Nucleoside and nucleotide synthesis: Design and synthesise a diverse range of chemically modified nucleosides and nucleotides (base, sugar and backbone modifications), with emphasis on nucleoside diphosphates and triphosphates

- Phosphorylation chemistry: Develop and optimise robust, reproducible routes to mono-, di- and triphosphates and related analogues, including cap analogues where relevant

- Purification: Purify polar, charged nucleotide species to high purity using ion-exchange, reversed-phase and ion-pair HPLC, and other chromatographic techniques

- Characterisation: Confirm the identity, purity and stability of products using HPLC, LC-MS, NMR, and UV spectroscopy

- Process improvement: Optimise and scale synthesis and purification workflows to improve yield, efficiency and reproducibility

- Troubleshooting: Diagnose and resolve challenges across synthesis, work-up, purification and analysis

- Oligonucleotide support (as skills allow): Contribute to solid-phase oligonucleotide synthesis, purification and analysis, and to the incorporation of modified nucleotides into RNA by chemical or enzymatic methods

- Collaboration: Work closely with other chemistry, RNA biology, formulation and process development colleagues to integrate modified building blocks into RNA and drug development pipelines

- Documentation: Maintain clear, accurate records of experiments, methods and results

Essential Qualifications & Experience

- PhD in Organic Chemistry or Medicinal Chemistry (recent graduates welcome), or a Master’s degree with substantial relevant industrial experience

- Strong, demonstrable background in nucleoside and nucleotide synthesis, including chemical modifications

- Hands-on experience synthesising and handling nucleoside diphosphates and/or triphosphates

- Solid expertise in chromatographic purification of polar, charged molecules, including HPLC

- Proficiency in analytical characterisation of nucleotides and oligonucleotide

- Strong problem-solving skills and attention to detail

- Excellent communication and teamwork skills, with the ability to thrive in a fast-paced, interdisciplinary setting

Good to have

- Experience with solid-phase oligonucleotide synthesis, including purification and analysis

- Experience with enzymatic RNA synthesis (e.g. IVT) and mRNA capping strategies

- Experience handling RNA and downstream processing

- Process development or scale-up experience

ScionxBio is an equal opportunities employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. We particularly welcome applications from people who are underrepresented in the sciences