Daniel E. Fitzpatrick

Organic Synthesis: March of the Machines

Organic synthesis is changing; in a world where budgets are constrained and the environmental impacts of practice are scrutinized, it is increasingly recognized that the efficient use of human resource is just as important as material use. New technologies and machines have found use as methods for transforming the way we work, addressing these issues encountered in research laboratories by enabling chemists to adopt a more holistic systems approach in their work. Modern developments in this area promote a multi-disciplinary approach and work is more efficient as a result. This Review focuses on the concepts, procedures and methods that have far-reaching implications in the chemistry world. Technologies have been grouped as topics of opportunity and their recent applications in innovative research laboratories are described.

Machine‐Assisted Organic Synthesis

Abstract In this Review we describe how the advent of machines is impacting on organic synthesis programs, with particular emphasis on the practical issues associated with the design of chemical reactors. In the rapidly changing, multivariant environment of the research laboratory, equipment needs to be modular to accommodate high and low temperatures and pressures, enzymes, multiphase systems, slurries, gases, and organometallic compounds. Additional technologies have been developed to facilitate more specialized reaction techniques such as electrochemical and photochemical methods. All of these areas create both opportunities and challenges during adoption as enabling technologies.

A Systems Approach towards an Intelligent and Self‐Controlling Platform for Integrated Continuous Reaction Sequences

Performing reactions in flow can offer major advantages over batch methods. However, laboratory flow chemistry processes are currently often limited to single steps or short sequences due to the complexity involved with operating a multi-step process. Using new modular components for downstream processing, coupled with control technologies, more advanced multi-step flow sequences can be realized. These tools are applied to the synthesis of 2-aminoadamantane-2-carboxylic acid. A system comprising three chemistry steps and three workup steps was developed, having sufficient autonomy and self-regulation to be managed by a single operator.

Flow Chemistry Meets Advanced Functional Materials

Flow chemistry and continuous processing techniques are beginning to have a profound impact on the production of functional materials ranging from quantum dots, nanoparticles and metal organic frameworks to polymers and dyes. These techniques provide robust procedures which not only enable accurate control of the product materials properties but they are also ideally suited to conducting experiments on scale. The modular nature of flow and continuous processing equipment rapidly facilitates reaction optimisation and variation in function of the products.

Enabling Technologies for the Future of Chemical Synthesis

Technology is evolving at breakneck pace, changing the way we communicate, travel, find out information, and live our lives. Yet chemistry as a science has been slower to adapt to this rapidly shifting world. In this Outlook we use highlights from recent literature reports to describe how progresses in enabling technologies are altering this trend, permitting chemists to incorporate new advances into their work at all levels of the chemistry development cycle. We discuss the benefits and challenges that have arisen, impacts on academic–industry relationships, and future trends in the area of chemical synthesis.

Engineering chemistry: integrating batch and flow reactions on a single, automated reactor platform

Synthesis chemistry need not be limited to either only batch or only flow; rather, in the future we expect that it will consist of an amalgamation of the best and most appropriate methods. We have therefore devised a single reactor platform to conduct both batch and flow reactions, either singly or in concert, using open source technologies to automate, control and monitor individual processes. We illustrate this concept with the multistep synthesis of 5-methyl-4-propylthiophene-2-carboxylic acid to showcase the utility of this approach in a telescoped manner. Automated downstream processing techniques, consisting of continuous extraction and solvent switching steps, were also included, further freeing the chemist from routine laboratory tasks.

In-line separation of multicomponent reaction mixtures using a new semi-continuous supercritical fluid chromatography system

A new bespoke semi-continuous parallel column supercritical fluid chromatography unit has been developed that solves the problem of effective separation of continuous, multicomponent reaction mixtures. It enables the rapid in-line separation of crude mixtures produced during batch and continuous flow reactions. It overcomes limitations inherent to other systems, enabling it to collect up to five individual fractions from mixtures with any number of constituent components, and adds new machinery to aid the modern synthetic chemist. The success of the system was exemplified using two Appel-type reactions, enabling the recovery of 81% of 1-bromoethylbenzene (with a first pass purity of 92%) and 89% of an intermediate to the anti-cancer drug candidate AZ82 (>99% purity) from batch mixtures. As a notable example, the system was also used in a telescoped flow process to separate an intermediate during the synthesis of isoniazid. In this case, the three-stage synthesis was operated at steady state for four hours during which time 96% recovery of the intermediate, isonicotinamide, was attained (with a purity of >99%).

Research data supporting “A Parallel Column Supercritical Fluid Chromatography System for Continuous Purification”

The data is twofold. First is the individual chromatograms of each experiment highlighted in the publication. Second is the NMR spectra of the fractions separated during the experiments.