retrosynthesis
(2)
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.
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.