70. A Convergent Continuous Multistep Process for the Preparation of C4-Oxime-Substituted Thiazoles

Edouard Godineau, Claudio Battilocchio, Matthias Lehmann, Steven V Ley, Ricardo Labes, Letitia Birnoschi, Srinivas Subramanian, C. S Prasanna, Amol Gorde, Mahesh Kalbagh, Vivek Khade, Anton Scherrer, and Anthony Cornelius Cornelius O’Sullivan, Organic Process Research & Development, (2018) DOI: 10.1021/acs.oprd.8b00095

We report a strategy designed for the rapid and convergent assembly of C4-oxime substituted thiazoles. Our approach relied on 3-bromo-2-oxopropanal O-methyl oxime 7 as a key building block. A three-step sequence to 7 was designed, which for safety concerns, could only be operated in batch mode on limited scales (<< 100g). We describe herein how we addressed such a limitation, by designing a multistep continuous synthesis of this intermediate and further demonstrate the advantages of flow reactor configuration upon scaling up.