retrosynthesis
(4)
Zlatko Jončev
Zlatko Jončev is the co-founder and CEO of b-12 (b12 Labs), a Y Combinator S25 startup building AI agents that plan and run chemical synthesis for pharma and biotech. A former national chemistry olympiad champion turned organic chemist, he earned a PhD in Basel, trained as a medicinal chemist at Roche, and did his postdoc in EPFL's Lab of Artificial Chemical Intelligence, where he met co-founder Andres Bran. b-12 aims to shrink early-stage drug discovery from years to months by making molecules that are otherwise hard to make.
b12 Labs
b12 Labs is a San Francisco startup (Y Combinator S25) building AI agents for pharmaceutical and biotech chemistry. Its platform designs synthesis routes, plans and optimizes reactions, and turns those plans into robot-ready code for automated labs, aiming to compress early-stage drug discovery from years to months. The company was founded in 2025 by chemists Zlatko Joncev and Andres Bran, who met at EPFL's Lab of Artificial Chemical Intelligence.
Shreyans Chopra
Shreyans Chopra is the founder and CEO of Mstack, an AI-native specialty chemicals company based in Houston that helps North American and global buyers source custom chemicals from a diversified manufacturing network. A chartered accountant turned BCG consultant turned Lightspeed India investor, he started Mstack in July 2022 and scaled it to more than 100 enterprise customers and operational profitability, raising a $40 million Series A led by Lightspeed and Alpha Wave in 2024. In 2025 the company launched Chemstack AI, an R&D platform that compresses molecule synthesis timelines from roughly 18 months to days.
Mstack
Mstack is an AI-native chemical R&D and manufacturing company that helps enterprises source and produce custom specialty chemicals. It pairs a cross-border network of vetted suppliers across India, the Middle East and Asia with Chemstack AI, a closed-loop platform that designs and ranks synthetic routes to compress molecule development from roughly 18 months to days. Founded in 2022 by former Lightspeed investor Shreyans Chopra, the company serves 100+ enterprise customers and is backed by Lightspeed and Alpha Wave Global.