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Russo TVC, Sá MM. One‐Pot Synthesis of α‐Diazo‐γ,δ‐unsaturated Esters as Versatile Building Blocks for Functionalized Dienes, Cyclopentenes, and 5,7‐Fused Bicycles. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Theo V. C. Russo
- Departamento de Química Universidade Federal de Santa Catarina Florianópolis SC 88040-900 Brazil
| | - Marcus M. Sá
- Departamento de Química Universidade Federal de Santa Catarina Florianópolis SC 88040-900 Brazil
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Green SP, Wheelhouse KM, Payne AD, Hallett JP, Miller PW, Bull JA. On the Use of Differential Scanning Calorimetry for Thermal Hazard Assessment of New Chemistry: Avoiding Explosive Mistakes. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202007028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Sebastian P. Green
- Department of Chemistry Imperial College London Molecular Sciences Research Hub White City Campus, Wood Lane London W12 0BZ UK
- Department of Chemical Engineering Imperial College London South Kensington Campus, Exhibition Road London SW7 2AZ UK
| | - Katherine M. Wheelhouse
- Chemical Development Product Development & Supply GlaxoSmithKline GSK Medicines Research Centre Gunnels Wood Road Stevenage Hertfordshire SG1 2NY UK
| | - Andrew D. Payne
- Process Safety Clinical Supply Chain GlaxoSmithKline GSK Medicines Research Centre Gunnels Wood Road Stevenage Hertfordshire SG1 2NY UK
| | - Jason P. Hallett
- Department of Chemical Engineering Imperial College London South Kensington Campus, Exhibition Road London SW7 2AZ UK
| | - Philip W. Miller
- Department of Chemistry Imperial College London Molecular Sciences Research Hub White City Campus, Wood Lane London W12 0BZ UK
| | - James A. Bull
- Department of Chemistry Imperial College London Molecular Sciences Research Hub White City Campus, Wood Lane London W12 0BZ UK
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Green SP, Wheelhouse KM, Payne AD, Hallett JP, Miller PW, Bull JA. On the Use of Differential Scanning Calorimetry for Thermal Hazard Assessment of New Chemistry: Avoiding Explosive Mistakes. Angew Chem Int Ed Engl 2020; 59:15798-15802. [PMID: 32893978 DOI: 10.1002/anie.202007028] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Indexed: 01/05/2023]
Abstract
Differential scanning calorimetry (DSC) is increasingly used as evidence to support a favourable safety profile of novel chemistry, or to highlight the need for caution. DSC enables preliminary assessment of the thermal hazards of a potentially energetic compound. However, unlike other standard characterisation methods, which have well defined formats for reporting data, the current reporting of DSC results for thermal hazard assessment has shown concerning trends. Around half of all results in 2019 did not include experimental details required to replicate the procedure. Furthermore, analysis for thermal hazard assessment is often only conducted in unsealed crucibles, which could lead to misleading results and dangerously incorrect conclusions. We highlight the specific issues with DSC analysis of hazardous compounds currently in the organic chemistry literature and provide simple "best practice" guidelines which will give chemists confidence in reported DSC results and the conclusions drawn from them.
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Affiliation(s)
- Sebastian P Green
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London, W12 0BZ, UK.,Department of Chemical Engineering, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, UK
| | - Katherine M Wheelhouse
- Chemical Development, Product Development & Supply, GlaxoSmithKline, GSK Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2NY, UK
| | - Andrew D Payne
- Process Safety, Clinical Supply Chain, GlaxoSmithKline, GSK Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire, SG1 2NY, UK
| | - Jason P Hallett
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, Exhibition Road, London, SW7 2AZ, UK
| | - Philip W Miller
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London, W12 0BZ, UK
| | - James A Bull
- Department of Chemistry, Imperial College London, Molecular Sciences Research Hub, White City Campus, Wood Lane, London, W12 0BZ, UK
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Green S, Wheelhouse KM, Payne AD, Hallett JP, Miller PW, Bull JA. Thermal Stability and Explosive Hazard Assessment of Diazo Compounds and Diazo Transfer Reagents. Org Process Res Dev 2020; 24:67-84. [PMID: 31983869 PMCID: PMC6972035 DOI: 10.1021/acs.oprd.9b00422] [Citation(s) in RCA: 122] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Indexed: 11/29/2022]
Abstract
Despite their wide use in academia as metal-carbene precursors, diazo compounds are often avoided in industry owing to concerns over their instability, exothermic decomposition, and potential explosive behavior. The stability of sulfonyl azides and other diazo transfer reagents is relatively well understood, but there is little reliable data available for diazo compounds. This work first collates available sensitivity and thermal analysis data for diazo transfer reagents and diazo compounds to act as an accessible reference resource. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and accelerating rate calorimetry (ARC) data for the model donor/acceptor diazo compound ethyl (phenyl)diazoacetate are presented. We also present a rigorous DSC dataset with 43 other diazo compounds, enabling direct comparison to other energetic materials to provide a clear reference work to the academic and industrial chemistry communities. Interestingly, there is a wide range of onset temperatures (T onset) for this series of compounds, which varied between 75 and 160 °C. The thermal stability variation depends on the electronic effect of substituents and the amount of charge delocalization. A statistical model is demonstrated to predict the thermal stability of differently substituted phenyl diazoacetates. A maximum recommended process temperature (T D24) to avoid decomposition is estimated for selected diazo compounds. The average enthalpy of decomposition (ΔH D) for diazo compounds without other energetic functional groups is -102 kJ mol-1. Several diazo transfer reagents are analyzed using the same DSC protocol and found to have higher thermal stability, which is in general agreement with the reported values. For sulfonyl azide reagents, an average ΔH D of -201 kJ mol-1 is observed. High-quality thermal data from ARC experiments shows the initiation of decomposition for ethyl (phenyl)diazoacetate to be 60 °C, compared to that of 100 °C for the common diazo transfer reagent p-acetamidobenzenesulfonyl azide (p-ABSA). The Yoshida correlation is applied to DSC data for each diazo compound to provide an indication of both their impact sensitivity (IS) and explosivity. As a neat substance, none of the diazo compounds tested are predicted to be explosive, but many (particularly donor/acceptor diazo compounds) are predicted to be impact-sensitive. It is therefore recommended that manipulation, agitation, and other processing of neat diazo compounds are conducted with due care to avoid impacts, particularly in large quantities. The full dataset is presented to inform chemists of the nature and magnitude of hazards when using diazo compounds and diazo transfer reagents. Given the demonstrated potential for rapid heat generation and gas evolution, adequate temperature control and cautious addition of reagents that begin a reaction are strongly recommended when conducting reactions with diazo compounds.
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Affiliation(s)
- Sebastian
P. Green
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, 80 Wood Lane, London W12 0BZ, U.K.
- Department
of Chemical Engineering, Imperial College
London, South Kensington Campus, Exhibition Road, London SW7 2AZ, U.K.
| | - Katherine M. Wheelhouse
- API Chemistry, Product Development & Supply and Process Safety,
Pilot Plant Operations, GlaxoSmithKline,
GSK Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K.
| | - Andrew D. Payne
- API Chemistry, Product Development & Supply and Process Safety,
Pilot Plant Operations, GlaxoSmithKline,
GSK Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K.
| | - Jason P. Hallett
- Department
of Chemical Engineering, Imperial College
London, South Kensington Campus, Exhibition Road, London SW7 2AZ, U.K.
| | - Philip W. Miller
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, 80 Wood Lane, London W12 0BZ, U.K.
| | - James A. Bull
- Department
of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, 80 Wood Lane, London W12 0BZ, U.K.
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Dar'in D, Kantin G, Krasavin M. A 'sulfonyl-azide-free' (SAFE) aqueous-phase diazo transfer reaction for parallel and diversity-oriented synthesis. Chem Commun (Camb) 2019; 55:5239-5242. [PMID: 30985842 DOI: 10.1039/c9cc02042j] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Diazo transfer reactions are notoriously associated with the use of potentially explosive sulfonyl azides. The first 'sulfonyl-azide-free' (SAFE) protocol for producing diazo compounds from their active-methylene precursors via the Regitz diazo transfer reaction was developed and has displayed a remarkable substrate scope. It can be applied to generating arrays of diazo compounds for further evolution via combinatorial chemistry and a range of scaffold-generating transformations.
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Affiliation(s)
- Dmitry Dar'in
- Institute of Chemistry, Saint Petersburg State University, Saint Petersburg 199034, Russian Federation.
| | - Grigory Kantin
- Institute of Chemistry, Saint Petersburg State University, Saint Petersburg 199034, Russian Federation.
| | - Mikhail Krasavin
- Institute of Chemistry, Saint Petersburg State University, Saint Petersburg 199034, Russian Federation.
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