scholarly journals Metal-porphyrin catalyzed aziridination of α-methylstyrene: Batch vs. flow process

2017 ◽  
Vol 21 (04-06) ◽  
pp. 381-390 ◽  
Author(s):  
Daniela Intrieri ◽  
Sergio Rossi ◽  
Alessandra Puglisi ◽  
Emma Gallo
Keyword(s):  
Dft Calculations ◽  
Continuous Flow ◽  
Flow System ◽  
Reaction Times ◽  
Batch Process ◽  
Porphyrin Ring ◽  
Flow Conditions ◽  
Metal Porphyrin ◽  
Flow Process ◽  
Influence Of Substituents

This work describes the aziridination process of [Formula: see text]-methylstyrene by using electron poor aromatic azides in the presence of metal-based porphyrins as catalysts. Different ruthenium and cobalt-based porphyrins were successfully employed for the synthesis of [Formula: see text]-aryl aziridines performed under a traditional batch methodology and under continuous flow conditions. In general, yields obtained using ruthenium-based catalysts in a traditional batch process were higher than those observed when the reaction was performed under flow conditions. However, cobalt-based porphyrins showed better activities and short reaction times when employed in a flow system process. DFT calculations were also performed in order to understand the influence of substituents on the porphyrin ring in the aziridination process.

scholarly journals Achieving selectivity in porphyrin bromination through a DoE-driven optimization under continuous flow conditions

2020 ◽  
Author(s):  
Paolo Zardi ◽  
Michele Maggini ◽  
Tommaso Carofiglio
Keyword(s):  
Reaction Time ◽  
Design Of Experiment ◽  
Continuous Flow ◽  
Optimization Process ◽  
Porphyrin Ring ◽  
Flow Conditions ◽  
Reaction Parameters ◽  
Synthetic Procedure ◽  
Relevant Factors ◽  
Post Functionalization

AbstractThe post-functionalization of porphyrins through the bromination in β position of the pyrrolic rings is a relevant transformation because the resulting bromoderivatives are useful synthons to covalently link a variety of chemical architectures to a porphyrin ring. However, single bromination of porphyrins is a challenging reaction for the abundancy of reactive β-pyrrolic positions in the aromatic macrocycle. We herein report a synthetic procedure for the efficient preparation of 2-bromo-5,10,15,20-tetraphenylporphyrin (1) under continuous flow conditions. The use of flow technology allows to reach an accurate control over critical reaction parameters such as temperature and reaction time. Furthermore, by performing the optimization process through a statistical DoE (Design of Experiment) approach, these parameters could be properly adjusted with a limited number of experiments. This process led us to a better understanding of the relevant factors that govern porphyrins monobromination and to obtain compound 1 with an unprecedent 80% yield.

scholarly journals The Eschenmoser coupling reaction under continuous-flow conditions

2011 ◽  
Vol 7 ◽  
pp. 1164-1172 ◽  
Author(s):  
Sukhdeep Singh ◽  
J Michael Köhler ◽  
Andreas Schober ◽  
G Alexander Groß
Keyword(s):  
Continuous Flow ◽  
Elevated Temperatures ◽  
Reaction Times ◽  
Coupling Reaction ◽  
Flow Chemistry ◽  
Flow Conditions ◽  
Reaction Conditions ◽  
Bond Forming ◽  
Carbon Carbon Bond ◽  
Reaction Proceeds

The Eschenmoser coupling is a useful carbon–carbon bond forming reaction which has been used in various different synthesis strategies. The reaction proceeds smoothly if S-alkylated ternary thioamides or thiolactames are used. In the case of S-alkylated secondary thioamides or thiolactames, the Eschenmoser coupling needs prolonged reaction times and elevated temperatures to deliver valuable yields. We have used a flow chemistry system to promote the Eschenmoser coupling under enhanced reaction conditions in order to convert the demanding precursors such as S-alkylated secondary thioamides and thiolactames in an efficient way. Under pressurized reaction conditions at about 220 °C, the desired Eschenmoser coupling products were obtained within 70 s residence time. The reaction kinetics was investigated and 15 examples of different building block combinations are given.

scholarly journals Dimeric cyclobutane formation under continuous flow conditions using organophotoredox catalysed [2+2]-cycloaddition

2021 ◽  
Author(s):  
Helena Grantham ◽  
Marc Kimber
Keyword(s):  
Natural Products ◽  
Continuous Flow ◽  
Reaction Times ◽  
Functional Materials ◽  
Synthetic Route ◽  
Flow Conditions ◽  
Reaction Conditions ◽  
New Class ◽  
Cyclobutane Dimers ◽  
Flow Study

Radical cation-initiated dimerization of electron rich alkenes is an expedient method for the synthesis of cyclobutanes. By merging organophotoredox catalysis and continuous flow technology a batch versus continuous flow study has been performed providing a convenient synthetic route to an important carbazole cyclobutane material dimer t-DCzCB using less only 0.1 mol% of an organophotoredox catalyst. The scope of this methodology was explored giving a new class of functional materials, as well as an improved synthetic route to styrene based lignan dimeric natural products. The cyclobutane dimers could be isolated in higher chemical yields under continuous flow conditions and reaction times were reduced significantly compared to traditional batch reaction conditions.

scholarly journals Continuous flow synthesis of α-aryl-α-aminophosphonates

2019 ◽  
Vol 91 (1) ◽  
pp. 67-76 ◽  
Author(s):  
Erika Bálint ◽  
Ádám Tajti ◽  
Katalin Ladányi-Pára ◽  
Nóra Tóth ◽  
Béla Mátravölgyi ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Reaction Times ◽  
Primary Amines ◽  
Flow Process ◽  
Flow Synthesis ◽  
Microwave Reactor ◽  
Dialkyl Phosphites ◽  
Benzaldehyde Derivatives

AbstractThe synthesis of α-aryl-α-aminophosphonates was performed by the three-component Kabachnik-Fields reaction of primary amines, benzaldehyde derivatives and dialkyl phosphites in a continuous flow microwave reactor. The target compounds could be obtained in high (~90%) yields without any catalyst in simple alcohols as the solvent. The flow process elaborated required shorter reaction times and lower excess of the reagent, as compared to the “traditional” batch reactions, and allowed the synthesis of the α-aminophosphonates on a somewhat larger scale.

scholarly journals Bismuth Subnitrate-Catalyzed Markovnikov-Type Alkyne Hydrations under Batch and Continuous Flow Conditions

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2864
Author(s):  
Zsanett Szécsényi ◽  
Ferenc Fülöp ◽  
Sándor B. Ötvös
Keyword(s):  
Continuous Flow ◽  
Reaction Medium ◽  
Batch Process ◽  
Packed Bed ◽  
Methyl Ketones ◽  
Flow Conditions ◽  
Efficient Catalyst ◽  
Ready Availability ◽  
Bismuth Subnitrate ◽  
Terminal Acetylenes

Bismuth subnitrate is reported herein as a simple and efficient catalyst for the atom-economical synthesis of methyl ketones via Markovnikov-type alkyne hydration. Besides an effective batch process under reasonably mild conditions, a chemically intensified continuous flow protocol was also developed in a packed-bed system. The applicability of the methodologies was demonstrated through hydration of a diverse set of terminal acetylenes. By simply switching the reaction medium from methanol to methanol-d4, valuable trideuteromethyl ketones were also prepared. Due to the ready availability and nontoxicity of the heterogeneous catalyst, which eliminated the need for any special additives and/or harmful reagents, the presented processes display significant advances in terms of practicality and sustainability.

Highly Enantioselective Immobilized Prolinamide-Catalyzed Aldol Reactions in Continuous-Flow Systems: Effect of Water on Catalyst Lifetime and Application to the Synthesis of a Chiral Fenpentadiol Analogue

2021 ◽  
Author(s):  
Caizhen Yue ◽  
Yasuhiro Yamashita ◽  
Shu Kobayashi
Keyword(s):  
Continuous Flow ◽  
Flow System ◽  
Aldol Reactions ◽  
Flow Conditions ◽  
Effect Of Water ◽  
Flow Systems ◽  
First Time ◽  
Catalyst Lifetime

Catalytic enantioselective aldol reactions of trifluoroacetophenones with ketones under continuous-flow conditions have been developed for the first time by using polystyrene-supported prolinamides. The robustness of the flow system was demonstrated...

scholarly journals Cultivation of a cellulolytic microbial community under continuous flow conditions

2021 ◽  
Author(s):  
David Jenkins
Keyword(s):  
Flow Rate ◽  
Continuous Flow ◽  
Microbial Consortium ◽  
Flow System ◽  
Cellulose Degradation ◽  
Cellulose Hydrolysis ◽  
Flow Conditions ◽  
Continuous Flow System ◽  
Enrichment Process ◽  
High Ethanol

A stable microbial consortium capable of cellulose hydrolysis under initial aerobic conditions has been enriched in a continuous flow system. Anaerobic conditions were created and maintained within the flow system using only microbial metabolism. A DGGE community profile of samples taken throughout the enrichment process indicates that the community stabilized upon entry into the continuous flow system, and maintained function and members throughout. The effect of flow rate on cellulose degradation and end product production was assessed. The cellulose degradation rate was found to be notably faster at a flow rate of 0.1 ml/min (D 0.75/hr) than a flow rate of 0.2 ml/min (D1.50/hr). Furthermore, an ethanol to acetate ratio nearly 8 times higher than previously reported values in the literature was also observed at 0.1 ml/min (D0.75/hr). With reduced flow rate and high ethanol to acetate ratios, the enriched community may be well suited for consolidate bioprocessing.

Photodecarboxylative Benzylations of N-Methoxyphthalimide under Batch and Continuous-Flow Conditions

2015 ◽  
Vol 68 (11) ◽  
pp. 1662 ◽  
Author(s):  
Hossein Mohammadkhani Pordanjani ◽  
Christian Faderl ◽  
Jun Wang ◽  
Cherie A. Motti ◽  
Peter C. Junk ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Methoxy Group ◽  
Irradiation Time ◽  
Batch Process ◽  
Flow Conditions ◽  
Reaction Conditions

A series of photodecarboxylative benzylations of N-methoxyphthalimide were successfully realised using easily accessible starting materials. The reactions proceeded smoothly and the corresponding benzylated hydroxyphthalimidines were obtained in moderate to good yields of 52–73 %. No competing photoinduced dealkoxylation of the N-methoxy group was observed. The reaction with potassium phenylacetate was subsequently investigated in an advanced continuous-flow photoreactor. The reactor allowed rapid optimization of the reaction conditions and gave the desired benzylated product in higher yield and shorter irradiation time compared with the batch process.

Versatile and scalable synthesis of cyclic organic carbonates under organocatalytic continuous flow conditions

2019 ◽  
Vol 9 (24) ◽  
pp. 6841-6851 ◽  
Author(s):  
Romaric Gérardy ◽  
Julien Estager ◽  
Patricia Luis ◽  
Damien P. Debecker ◽  
Jean-Christophe M. Monbaliu
Keyword(s):  
Continuous Flow ◽  
Flow Conditions ◽  
Flow Process ◽  
Organic Carbonates ◽  
Scalable Synthesis

A scalable intensified flow process for the preparation of cyclic organic carbonates relying on a cheap ammonium organocatalyst.

Reversal of the enantioselectivity in aldol addition over immobilized di- and tripeptides: studies under continuous flow conditions

RSC Advances ◽  
2014 ◽  
Vol 4 (106) ◽  
pp. 61611-61618 ◽  
Author(s):  
András Gurka ◽  
Imre Bucsi ◽  
Lenke Kovács ◽  
György Szőllősi ◽  
Mihály Bartók
Keyword(s):  
Continuous Flow ◽  
Flow System ◽  
Aldol Reactions ◽  
Flow Conditions ◽  
Continuous Flow System ◽  
System P ◽  
Aldol Addition

The reversal of the enantioselectivity in the heterogeneous asymmetric direct aldol reactions obtained over resin supported di- versus tripeptides was studied in a continuous-flow system.

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