Selective and Stepwise Functionalization of the Pyridazine Scaffold by Using Thio‐Substituted Pyridazine Building Blocks

We described a regioselective tri- and tetra-functionalization of the pyridazine scaffold using two readily available building blocks: 3-alkylthio-6-chloropyridazine and 3,4-bis(methylthio)-6-chloropyridazine by performing selective metalations with TMPMgCl ⋅ LiCl and catalyst-tuned cross-coupling reactions with arylzinc halides. Several of the resulting pyridazines were converted into more elaborated N-heterocycles such as thieno[2,3-c]pyridazines and 1H-pyrazolo[3,4-c]pyridazines

Exploiting Coordination Effects for the Regioselective Zincation of Diazines Using TMPZnX⋅LiX (X=Cl, Br)

A new method for regioselective zincations of challenging N-heterocyclic substrates such as pyrimidines and pyridazine was reported using bimetallic bases TMPZnX⋅LiX (TMP=2,2,6,6-tetramethylpiperidyl; X=Cl, Br). Reactions occurred under mild conditions (25-70 °C, using 1.75 equivalents of base without additives), furnishing 2-zincated pyrimidines and 3-zincated pyridazine, which were then trapped with a variety of electrophiles. Contrasting with other s-block metalating systems, which lack selectivity in their reactions even when operating at low temperatures, these mixed Li/Zn bases enabled unprecedented regioselectivities that cannot be replicated by either LiTMP nor Zn(TMP)2 on their own. Spectroscopic and structural interrogations of organometallic intermediates involved in these reactions have shed light on the complex constitution of reaction mixtures and the origins of their special reactivities

How Can Academia Help Industry Reduce the Footprint of Chemicals Manufacture?

Industrial representatives from the Swiss chemistry ecosystem met to formulate unmet needs in the field of sustainability and share the content of the exchange. The aim is to spark inspiration and trigger ambitious and pre-competitive projects collectively at the interface of the academic and industrial worlds, with the hope to profoundly change the current practices and provide an answer to some of the most urgent environmental challenges.  

Use of Renewable Resources Towards the Sustainable Production of Crop Protection Agents

Today, the production of food accounts for roughly one quarter of the anthropogenic greenhouse gas emissions. Since the 1970s, thanks to substantial research and development, the overall yield output in farm fields has increased by ca. 60%, while the net use of crop protection agents per square meter of farm field has been reduced by more than 90%. The development of modern crop protection agents remains an important need as new pests, diseases and weeds continue to affect crops. The vast majority of these effective solutions are manufactured using raw materials that ultimately come from fossil resources. In this article, we are touring within the agrochemical landscape to provide the reader with an overview of concrete examples on how in this industrial field, renewable and sustainable raw materials have been used to produce active ingredients. We are also discussing the opportunities for future development as well as some of the challenges and needs that are emerging

Building up a Continuous Flow Platform as an Enabler to the Preparation of Intermediates on Kilogram Scale

The following outlook describes the strategy we followed at Syngenta R&D to build and develop an effective flow chemistry platform which could fit a precise business purpose. In this account, we give insight into specific chemistry challenges encountered and addressed using continuous flow chemistry. The conclusions of the outlook outline the future of our strategy with a perspective on the technology within our business