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Synthesis of pyrazoles by 1,3‐dipolar cycloaddition under aqueous micellar catalysis. European J Org Chem 2022. [DOI: 10.1002/ejoc.202200632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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2
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Pascual G, Donnellan P, Glennon B, Wood B, Jones RC. Design and Optimization of the Single-Stage Continuous Mixed Suspension-Mixed Product Removal Crystallization of 2-Chloro- N-(4-methylphenyl)propenamide. ACS OMEGA 2022; 7:13676-13686. [PMID: 35559147 PMCID: PMC9088942 DOI: 10.1021/acsomega.1c07228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 03/08/2022] [Indexed: 06/15/2023]
Abstract
A continuously operated single-stage mixed suspension-mixed product removal (MSMPR) crystallizer was developed for the continuous cooling crystallization of 2-chloro-N-(4-methylphenyl)propanamide (CNMP) in toluene from 25 to 0 °C. The conversion of the previous batch to a continuous process was key to developing a methodology linking the synthesis and purification unit operations of CNMP and gave further insight in the development of continuous process trains for active pharmaceutical ingredient materials. By monitoring how parameters such as cooling and agitation rates influence particle size and the yield, two batch start-up strategies were compared. The second part of the study focused on developing and optimizing the continuous cooling crystallization of CNMP in the MSMPR crystallizer in relation to the yield by determining the effects of varying the residence time and the agitation rates. During the MSMPR operation, the plot of the focused beam reflectance measurement total counts versus time oscillates and reaches an unusual state of control. Despite the oscillations, the dissolved concentration was constant. The yield and production rate from the system were constant after two residence times, as supported by FTIR data. The overall productivity was higher at shorter residence times (τ), and a productivity of 69.51 g/h for τ = 20 min was achieved for the isolation of CNMP.
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Affiliation(s)
- Gladys
Kate Pascual
- Synthesis
and Solid State Pharmaceutical Centre (SSPC), School of Chemical and
Bioprocess Engineering, University College
Dublin, Belfield, Dublin 4, Ireland
| | - Philip Donnellan
- Synthesis
and Solid State Pharmaceutical Centre (SSPC), School of Chemical and
Bioprocess Engineering, University College
Dublin, Belfield, Dublin 4, Ireland
| | - Brian Glennon
- Synthesis
and Solid State Pharmaceutical Centre (SSPC), School of Chemical and
Bioprocess Engineering, University College
Dublin, Belfield, Dublin 4, Ireland
- APC
Ltd, Cherrywood Business
Park, Loughlinstown, Dublin D18 DH50, Ireland
| | - Barbara Wood
- Synthesis
and Solid State Pharmaceutical Centre (SSPC), School of Chemical and
Bioprocess Engineering, University College
Dublin, Belfield, Dublin 4, Ireland
- APC
Ltd, Cherrywood Business
Park, Loughlinstown, Dublin D18 DH50, Ireland
| | - Roderick C. Jones
- Synthesis
and Solid State Pharmaceutical Centre (SSPC), School of Chemical and
Bioprocess Engineering, University College
Dublin, Belfield, Dublin 4, Ireland
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Allaka BS, Basavoju S, Gamidi RK. Transition Metal‐ and Oxidant‐Free Regioselective Synthesis of 3,4,5‐Trisubstituted Pyrazoles by Means of [3+2] Cycloaddition Reactions. ChemistrySelect 2022. [DOI: 10.1002/slct.202200605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Bhargava Sai Allaka
- Department of Chemistry National Institute of Technology Warangal Hanamkonda 506 004 Telangana India
| | - Srinivas Basavoju
- Department of Chemistry National Institute of Technology Warangal Hanamkonda 506 004 Telangana India
| | - Rama Krishna Gamidi
- Organic Chemistry Division CSIR-National Chemical Laboratory Dr. Homi Bhabha Road Pune Maharashtra 411 008 India
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Chandrasekharan SP, Dhami A, Kumar S, Mohanan K. Recent advances in pyrazole synthesis employing diazo compounds and synthetic analogues. Org Biomol Chem 2022; 20:8787-8817. [DOI: 10.1039/d2ob01918c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This review summarizes the recent developments in the construction of pyrazoles using diazo compounds, nitrile imines and their synthetic equivalents.
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Affiliation(s)
- Sanoop P. Chandrasekharan
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Anamika Dhami
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Sandeep Kumar
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Kishor Mohanan
- Medicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
- Academy of Scientific and Innovative Research, Ghaziabad-201002, India
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Alam RM, Keating JJ. Regioselective N-alkylation of the 1 H-indazole scaffold; ring substituent and N-alkylating reagent effects on regioisomeric distribution. Beilstein J Org Chem 2021; 17:1939-1951. [PMID: 34386104 PMCID: PMC8353588 DOI: 10.3762/bjoc.17.127] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 07/23/2021] [Indexed: 11/23/2022] Open
Abstract
The indazole scaffold represents a promising pharmacophore, commonly incorporated in a variety of therapeutic drugs. Although indazole-containing drugs are frequently marketed as the corresponding N-alkyl 1H- or 2H-indazole derivative, the efficient synthesis and isolation of the desired N-1 or N-2 alkylindazole regioisomer can often be challenging and adversely affect product yield. Thus, as part of a broader study focusing on the synthesis of bioactive indazole derivatives, we aimed to develop a regioselective protocol for the synthesis of N-1 alkylindazoles. Initial screening of various conditions revealed that the combination of sodium hydride (NaH) in tetrahydrofuran (THF) (in the presence of an alkyl bromide), represented a promising system for N-1 selective indazole alkylation. For example, among fourteen C-3 substituted indazoles examined, we observed > 99% N-1 regioselectivity for 3-carboxymethyl, 3-tert-butyl, 3-COMe, and 3-carboxamide indazoles. Further extension of this optimized (NaH in THF) protocol to various C-3, -4, -5, -6, and -7 substituted indazoles has highlighted the impact of steric and electronic effects on N-1/N-2 regioisomeric distribution. For example, employing C-7 NO2 or CO2Me substituted indazoles conferred excellent N-2 regioselectivity (≥ 96%). Importantly, we show that this optimized N-alkylation procedure tolerates a wide structural variety of alkylating reagents, including primary alkyl halide and secondary alkyl tosylate electrophiles, while maintaining a high degree of N-1 regioselectivity.
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Affiliation(s)
- Ryan M Alam
- Analytical and Biological Chemistry Research Facility (ABCRF), University College Cork, College Road, Cork, T12 YN60, Ireland
- School of Chemistry, Kane Building, University College Cork, T12 YN60, Ireland
| | - John J Keating
- Analytical and Biological Chemistry Research Facility (ABCRF), University College Cork, College Road, Cork, T12 YN60, Ireland
- School of Chemistry, Kane Building, University College Cork, T12 YN60, Ireland
- School of Pharmacy, Pharmacy Building, University College Cork, T12 YN60, Ireland
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Devi L, Sharma G, Kant R, Shukla SK, Rastogi N. Regioselective synthesis of functionalized pyrazole-chalcones via a base mediated reaction of diazo compounds with pyrylium salts. Org Biomol Chem 2021; 19:4132-4136. [PMID: 33870359 DOI: 10.1039/d1ob00274k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A base-mediated reaction of triaryl/alkyl pyrylium tetrafluoroborate salts with α-diazo-phosphonates, sulfones and trifluoromethyl compounds affords the corresponding functionalized pyrazole-chalcones as 5-P-5 and 3-P-3 tautomeric mixture. The reaction proceeds through an initial nucleophilic addition of diazo substrates to pyrylium salts followed by a base-mediated pyrylium ring-opening and intramolecular 1,5-cyclization to afford formal 1,3-dipolar cycloaddition products. The products underwent a Nazarov-type cyclization upon hydride reduction followed by acidic-workup, furnishing the corresponding indenyl-pyrazoles in high yields.
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Affiliation(s)
- Lalita Devi
- Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow-226031, India. and Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Gaurav Sharma
- Sophisticated Analytical Instrument Facility, CSIR-Central Drug Research Institute, Lucknow-226031, India. and Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Ruchir Kant
- Molecular & Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow-226031, India
| | - Sanjeev K Shukla
- Sophisticated Analytical Instrument Facility, CSIR-Central Drug Research Institute, Lucknow-226031, India. and Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Namrata Rastogi
- Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow-226031, India. and Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
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Kearney AM, Murphy L, Murphy CC, Eccles KS, Lawrence SE, Collins SG, Maguire AR. Synthesis and reactivity of α-sulfenyl-β-chloroenones, including oxidation and Stille cross-coupling to form chalcone derivatives. Tetrahedron 2021. [DOI: 10.1016/j.tet.2021.132091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Flynn AJ, Ford A, Maguire AR. Synthetic and mechanistic aspects of sulfonyl migrations. Org Biomol Chem 2020; 18:2549-2610. [DOI: 10.1039/c9ob02587a] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Sulfonyl migrations, frequently described as ‘unusual’ or ‘unexpected’, from the last 20 years, including 1,2-, 1,3-, 1,4-, 1,5-, 1,6- and 1,7-sulfonyl shifts, through either radical or polar processes, either inter- or intramolecularly are reviewed.
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Affiliation(s)
- Aaran J. Flynn
- School of Chemistry
- Analytical and Biological Research Facility
- Synthesis and Solid State Pharmaceutical Centre
- University College Cork
- Cork
| | - Alan Ford
- School of Chemistry
- Analytical and Biological Research Facility
- University College Cork
- Cork
- Ireland
| | - Anita R. Maguire
- School of Chemistry and School of Pharmacy
- Analytical and Biological Research Facility
- Synthesis and Solid State Pharmaceutical Centre
- University College Cork
- Cork
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