New benzotriazole-based reagents for the phosphonylation of various N-, O-, and S-nucleophiles

Panmand, Deepak S.; Tiwari, Anand D.; Panda, Siva S.; Monbaliu, Jean‐Christophe M.; Beagle, Lucas K.; Asiri, Abdullah M.; Stevens, Christian V.; Steel, Peter J.; Hall, C. Dennis; Katritzky, Alan R.

doi:10.1016/j.tetlet.2014.07.057

Cited by 66 publications

(19 citation statements)

References 39 publications

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“…Moreover, the base played a second crucial role in this mechanism; indeed, we were able to isolate and characterize the diethyl methyl phosphate G as a byproduct generated during this reaction (see SI). We thus proposed that sodium methylate generated in the reaction medium can attack the phosphoramidate intermediate F to release the diethyl methyl phosphate G and the phthalazine H . This last intermediate is in a very balanced equilibrium with the final product I.…”

Section: Resultsmentioning

confidence: 99%

Phosphoramidates as Transient Precursors of Nitrogen‐Centered Radical Under Visible‐Light Irradiation: Application to the Synthesis of Phthalazine Derivatives

et al. 2020

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Phosphoramidates are for the first time presented as efficient N-Centered Radical (NCR) precursors under visible-light irradiation. More precisely among this class of phosphorus-derived compounds, we studied the radical reactivity of phosphonohydrazones, under mild reaction conditions, which allowed the synthesis of a wide and diversified library of the scarcely reported phthalazine scaffold. Mechanistic investigations confirmed the formation of a NCR from these brand-new phosphonohydrazones (derivatived from phosphoramidates), which were further engaged in an intramolecular 6-exo-dig cyclization to provide phthalazines. Compared to other pre-activated moieties, the phosphoramidate group is self-immolative, thus enhancing its attractiveness for the CÀ N bond formation.

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Section: Resultsmentioning

confidence: 99%

Phosphoramidates as Transient Precursors of Nitrogen‐Centered Radical Under Visible‐Light Irradiation: Application to the Synthesis of Phthalazine Derivatives

et al. 2020

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“…The conjugated dienes 2 and 3 ( Figure 2 ) were synthesized by reaction of mesityl oxide with phosphorus acid and hypophosphorus acid, respectively [ 55 , 56 ]. It was described in the patent that these compounds can be used as flame retardants, potentially in the plastic industry or in textile coatings.…”

Section: Flame Retardants With P-c Aliphatic Bomentioning

confidence: 99%

Recent Developments in Organophosphorus Flame Retardants Containing P-C Bond and Their Applications

et al. 2017

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Organophosphorus compounds containing P-C bonds are increasingly developed as flame retardant additives due to their excellent thermal and hydrolytic stability and ease of synthesis. The latest development (since 2010) in organophosphorus flame retardants containing P-C bonds summarized in this review. In this review, we have broadly classified such phosphorus compounds based on the carbon unit linked to the phosphorus atom i.e., could be a part of either an aliphatic or an aromatic unit. We have only considered those published literature where a P-C bond was created as a part of synthetic strategy to make either an intermediate or a final organophosphorus compound with an aim to use it as a flame retardant. General synthetic strategies to create P-C bonds are briefly discussed. Most popular synthetic strategies used for developing P-C containing phosphorus based flame retardants include Michael addition, Michaelis–Arbuzov, Friedels–Crafts and Grignard reactions. In general, most flame retardant derivatives discussed in this review have been prepared via a one- to two-step synthetic strategy with relatively high yields greater than 80%. Specific examples of P-C containing flame retardants synthesized via suitable synthetic strategy and their applications on various polymer systems are described in detail. Aliphatic phosphorus compounds being liquids or low melting solids are generally applied in polymers via coatings (cellulose) or are incorporated in the bulk of the polymers (epoxy, polyurethanes) during their polymerization as reactive or non-reactive additives. Substituents on the P atoms and the chemistry of the polymer matrix greatly influence the flame retardant behavior of these compounds (condensed phase vs. the gas phase). Recently, aromatic DOPO based phosphinate flame retardants have been developed with relatively higher thermal stabilities (>250 °C). Such compounds have potential as flame retardants for high temperature processable polymers such as polyesters and polyamides. A vast variety of P-C bond containing efficient flame retardants are being developed; however, further work in terms of their economical synthetic methods, detailed impact on mechanical properties and processability, long term durability and their toxicity and environmental impact is much needed for their potential commercial exploitations.

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“…28 However, regardless of the easy handling of this reaction, it has found no commercial successes as CCl 4 is a carcinogen and depletes the ozone. In these cases, P(O)─H bond has been transformed to P─Cl via the use of several chlorinating agents such as tert-butyl hypochlorite (t-BuOCl), 31 chlorine gas (Cl 2 ), 32-34 copper(II) chloride (CuCl 2 ), 35 sulfuryl chloride (SO 2 Cl 2 ), 36 n-chlorosuccinimide (NCS), 22,37 and trichloroisocyanuric acid (TCCA). In these cases, P(O)─H bond has been transformed to P─Cl via the use of several chlorinating agents such as tert-butyl hypochlorite (t-BuOCl), 31 chlorine gas (Cl 2 ), 32-34 copper(II) chloride (CuCl 2 ), 35 sulfuryl chloride (SO 2 Cl 2 ), 36 n-chlorosuccinimide (NCS), 22,37 and trichloroisocyanuric acid (TCCA).…”

Section: General Synthesis Methodsmentioning

confidence: 99%

Recent developments in P(O/S)–N containing flame retardants

Nazir

Gaan

2019

J of Applied Polymer Sci

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Synthesis of organophosphorus compounds containing nitrogen as heteroatom and its application as a flame retardant (FR) have attracted much attention in the academic and industrial communities over the past decade. Such compounds are relatively easy to synthesize and offer advantages such as high thermal stability, which is useful for high temperature processing, improved char stability, density, and yield during the thermal decomposition of polymer, and release phosphorus species active in the flame inhibition process. Though a variety of phosphorus-nitrogen (P-N) compounds can be found in the literature, this review mostly summarizes the recent (since 2013) development in phosphorus (O)-nitrogen containing flame retardants which have been published in peer-reviewed journals. General strategies of synthesizing P(O)-N compounds as FRs from various phosphorus-based starting materials are highlighted in this review. Some of the most common classes of researched P(O)-N containing compounds as FRs include the phosphinamides, phosphonamides, phosphoramides, phosphoramidates, phosphorodiamidates, phosphonamidates and their thio counterparts which are usually obtained via a one-or two-step synthetic strategy. Incorporation of these compounds as FRs in various polymer systems such as polyurethane, epoxy resins, polyamides, cellulose, polylactide, poly(butylene terephthalate), polycarbonates, and acrylonitrile-butadiene-styrene are discussed in detail in this review. Special emphasis on the various fire and thermal performances of the new materials are also summarized. The mechanical performance of new materials and the influence of these additives on polymer processing are also briefly discussed.

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New benzotriazole-based reagents for the phosphonylation of various N-, O-, and S-nucleophiles

Cited by 66 publications

References 39 publications

Phosphoramidates as Transient Precursors of Nitrogen‐Centered Radical Under Visible‐Light Irradiation: Application to the Synthesis of Phthalazine Derivatives

Phosphoramidates as Transient Precursors of Nitrogen‐Centered Radical Under Visible‐Light Irradiation: Application to the Synthesis of Phthalazine Derivatives

Recent Developments in Organophosphorus Flame Retardants Containing P-C Bond and Their Applications

Recent developments in P(O/S)–N containing flame retardants

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