10 research outputs found
Listeria monocytogenes in Milk Products
peer-reviewedMilk and milk products are frequently identified as vectors for transmission of Listeria monocytogenes. Milk can be contaminated at farm level either by indirect external contamination from the farm environment or less frequently by direct contamination of the milk from infection in the animal. Pasteurisation of milk will kill L. monocytogenes, but post-pasteurisation contamination, consumption of unpasteurised milk and manufacture of unpasteurised milk products can lead to milk being the cause of outbreaks of listeriosis. Therefore, there is a concern that L. monocytogenes in milk could lead to a public health risk. To protect against this risk, there is a need for awareness surrounding the issues, hygienic practices to reduce the risk and adequate sampling and analysis to verify that the risk is controlled. This review will highlight the issues surrounding L. monocytogenes in milk and milk products, including possible control measures. It will therefore create awareness about L. monocytogenes, contributing to protection of public health
SynthÚse et réactivité de nouveaux organophosphorés : nouvelles voies d'accÚs à des hétérocycles phosphorés.
Phosphorus atom have different chemical, electronic, and steric properties compared to those of carbon atom. Incorporating phosphorus in an organic compounds introduces unique properties into the system, which are not present in the carbon analoges, resulting in a compound electrochemical property which might give biological activities which could be interesting for pharmaceutical and material sciences. Nowadays, access to the phosphorus heterocycles remains a central concern in synthetic chemistry and has been the subject of several developments, probably due to their biological activities. In this context, our project goal was to develop new routes to a new phosphorus compounds particulary phosphorus heterocycles.First, we have developed a new familly of phosphines oxides which have been used to access for new phosphorus compounds. The α-functionalized phosphine oxides were obtained with a simple functionalization of lithium phosphides with various aldehydes. While oxaphosphinines were obtained using intramolecular hydrophosphorylation of alkynes in the presence of copper (I), via 6-exo-dig additions.In a second part of the work, we have described a simple access to new vinylphosphonates starting from a functional bisphosphonate and a new access way to a wide range of phosphoramidates using a phosphorochloridate as intermediate.Finally we described the access to a new family of oxaphosphinines and oxaphospholes or azaphospholes via an intramolecular Heck cross coupling according to 5 and 6-exo-trig additionsLâatome de phosphore possĂšde des propriĂ©tĂ©s chimiques, Ă©lectroniques et stĂ©rique trĂšs diffĂ©rentes de celle de lâatome de carbone. Lâincorporation du phosphore dans un motif organique peuvent apporter plusieurs avantages, ce qui explique leur intĂ©rĂȘt dans le domaine pharmaceutique et en sciences des matĂ©riaux. Câest pourquoi, lâaccĂšs Ă des hĂ©tĂ©rocycles phosphorĂ©s fait lâobjet, ces derniĂšres annĂ©es de nombreux dĂ©veloppement mĂ©thodologique dĂ» surement aux activitĂ©s biologiques quâils possĂšdent. Dans ce contexte lâobjet de cette thĂšse fut de dĂ©velopper de nouvelles voies dâaccĂšs Ă de nouveaux composĂ©s organophosphorĂ©s et en particulier des hĂ©tĂ©rocycles phosphorĂ©s.Dans une premiĂšre partie nous avons dĂ©crit une nouvelle famille dâoxydes de phosphines qui ont Ă©tĂ© valorisĂ© via deux rĂ©actions diffĂ©rentes. La premiĂšre est une fonctionnalisation des phosphures de lithium vis-Ă -vis de divers types dâaldĂ©hydes qui nous a permis dâaccĂ©der Ă une nouvelle famille dâoxydes de phosphines α-fonctionnalisĂ©. Tandis que la deuxiĂšme concerne une rĂ©action dâhydrophosphorylation intramolĂ©culaire dâalcyne catalysĂ© par le cuivre(I) conduit Ă une nouvelle famille dâoxaphosphinines via des additions 6-exo-dig.Dans une deuxiĂšme partie de ces travaux nous avons dĂ©crit Ă la fois une voie dâaccĂšs simple Ă un nouveau vinylphosphonate Ă partir dâun bisphosphonate fonctionnel et une nouvelle voie dâaccĂšs Ă une famille de phosphoramidates moyennant un phosphorochloridate comme intermĂ©diaire.Finalement nous avons dĂ©crit lâaccĂšs Ă une nouvelle famille dâoxaphosphinines et dâoxaphospholes ou dâazaphospholes via un couplage de Heck intramolĂ©culaire selon des addition 5 et 6-exo-trig
Synthesis and reactivity of new organophosphosphorus : new access to phosphorus heterocycles
Lâatome de phosphore possĂšde des propriĂ©tĂ©s chimiques, Ă©lectroniques et stĂ©rique trĂšs diffĂ©rentes de celle de lâatome de carbone. Lâincorporation du phosphore dans un motif organique peuvent apporter plusieurs avantages, ce qui explique leur intĂ©rĂȘt dans le domaine pharmaceutique et en sciences des matĂ©riaux. Câest pourquoi, lâaccĂšs Ă des hĂ©tĂ©rocycles phosphorĂ©s fait lâobjet, ces derniĂšres annĂ©es de nombreux dĂ©veloppement mĂ©thodologique dĂ» surement aux activitĂ©s biologiques quâils possĂšdent. Dans ce contexte lâobjet de cette thĂšse fut de dĂ©velopper de nouvelles voies dâaccĂšs Ă de nouveaux composĂ©s organophosphorĂ©s et en particulier des hĂ©tĂ©rocycles phosphorĂ©s.Dans une premiĂšre partie nous avons dĂ©crit une nouvelle famille dâoxydes de phosphines qui ont Ă©tĂ© valorisĂ© via deux rĂ©actions diffĂ©rentes. La premiĂšre est une fonctionnalisation des phosphures de lithium vis-Ă -vis de divers types dâaldĂ©hydes qui nous a permis dâaccĂ©der Ă une nouvelle famille dâoxydes de phosphines α-fonctionnalisĂ©. Tandis que la deuxiĂšme concerne une rĂ©action dâhydrophosphorylation intramolĂ©culaire dâalcyne catalysĂ© par le cuivre(I) conduit Ă une nouvelle famille dâoxaphosphinines via des additions 6-exo-dig.Dans une deuxiĂšme partie de ces travaux nous avons dĂ©crit Ă la fois une voie dâaccĂšs simple Ă un nouveau vinylphosphonate Ă partir dâun bisphosphonate fonctionnel et une nouvelle voie dâaccĂšs Ă une famille de phosphoramidates moyennant un phosphorochloridate comme intermĂ©diaire.Finalement nous avons dĂ©crit lâaccĂšs Ă une nouvelle famille dâoxaphosphinines et dâoxaphospholes ou dâazaphospholes via un couplage de Heck intramolĂ©culaire selon des addition 5 et 6-exo-trig.Phosphorus atom have different chemical, electronic, and steric properties compared to those of carbon atom. Incorporating phosphorus in an organic compounds introduces unique properties into the system, which are not present in the carbon analoges, resulting in a compound electrochemical property which might give biological activities which could be interesting for pharmaceutical and material sciences. Nowadays, access to the phosphorus heterocycles remains a central concern in synthetic chemistry and has been the subject of several developments, probably due to their biological activities. In this context, our project goal was to develop new routes to a new phosphorus compounds particulary phosphorus heterocycles.First, we have developed a new familly of phosphines oxides which have been used to access for new phosphorus compounds. The α-functionalized phosphine oxides were obtained with a simple functionalization of lithium phosphides with various aldehydes. While oxaphosphinines were obtained using intramolecular hydrophosphorylation of alkynes in the presence of copper (I), via 6-exo-dig additions.In a second part of the work, we have described a simple access to new vinylphosphonates starting from a functional bisphosphonate and a new access way to a wide range of phosphoramidates using a phosphorochloridate as intermediate.Finally we described the access to a new family of oxaphosphinines and oxaphospholes or azaphospholes via an intramolecular Heck cross coupling according to 5 and 6-exo-trig addition
SynthÚse et réactivité de nouveaux organophosphorés : nouvelles voies d'accÚs à des hétérocycles phosphorés.
Phosphorus atom have different chemical, electronic, and steric properties compared to those of carbon atom. Incorporating phosphorus in an organic compounds introduces unique properties into the system, which are not present in the carbon analoges, resulting in a compound electrochemical property which might give biological activities which could be interesting for pharmaceutical and material sciences. Nowadays, access to the phosphorus heterocycles remains a central concern in synthetic chemistry and has been the subject of several developments, probably due to their biological activities. In this context, our project goal was to develop new routes to a new phosphorus compounds particulary phosphorus heterocycles.First, we have developed a new familly of phosphines oxides which have been used to access for new phosphorus compounds. The α-functionalized phosphine oxides were obtained with a simple functionalization of lithium phosphides with various aldehydes. While oxaphosphinines were obtained using intramolecular hydrophosphorylation of alkynes in the presence of copper (I), via 6-exo-dig additions.In a second part of the work, we have described a simple access to new vinylphosphonates starting from a functional bisphosphonate and a new access way to a wide range of phosphoramidates using a phosphorochloridate as intermediate.Finally we described the access to a new family of oxaphosphinines and oxaphospholes or azaphospholes via an intramolecular Heck cross coupling according to 5 and 6-exo-trig additionsLâatome de phosphore possĂšde des propriĂ©tĂ©s chimiques, Ă©lectroniques et stĂ©rique trĂšs diffĂ©rentes de celle de lâatome de carbone. Lâincorporation du phosphore dans un motif organique peuvent apporter plusieurs avantages, ce qui explique leur intĂ©rĂȘt dans le domaine pharmaceutique et en sciences des matĂ©riaux. Câest pourquoi, lâaccĂšs Ă des hĂ©tĂ©rocycles phosphorĂ©s fait lâobjet, ces derniĂšres annĂ©es de nombreux dĂ©veloppement mĂ©thodologique dĂ» surement aux activitĂ©s biologiques quâils possĂšdent. Dans ce contexte lâobjet de cette thĂšse fut de dĂ©velopper de nouvelles voies dâaccĂšs Ă de nouveaux composĂ©s organophosphorĂ©s et en particulier des hĂ©tĂ©rocycles phosphorĂ©s.Dans une premiĂšre partie nous avons dĂ©crit une nouvelle famille dâoxydes de phosphines qui ont Ă©tĂ© valorisĂ© via deux rĂ©actions diffĂ©rentes. La premiĂšre est une fonctionnalisation des phosphures de lithium vis-Ă -vis de divers types dâaldĂ©hydes qui nous a permis dâaccĂ©der Ă une nouvelle famille dâoxydes de phosphines α-fonctionnalisĂ©. Tandis que la deuxiĂšme concerne une rĂ©action dâhydrophosphorylation intramolĂ©culaire dâalcyne catalysĂ© par le cuivre(I) conduit Ă une nouvelle famille dâoxaphosphinines via des additions 6-exo-dig.Dans une deuxiĂšme partie de ces travaux nous avons dĂ©crit Ă la fois une voie dâaccĂšs simple Ă un nouveau vinylphosphonate Ă partir dâun bisphosphonate fonctionnel et une nouvelle voie dâaccĂšs Ă une famille de phosphoramidates moyennant un phosphorochloridate comme intermĂ©diaire.Finalement nous avons dĂ©crit lâaccĂšs Ă une nouvelle famille dâoxaphosphinines et dâoxaphospholes ou dâazaphospholes via un couplage de Heck intramolĂ©culaire selon des addition 5 et 6-exo-trig
Direct Functionalization of Lithium Phosphine Oxides Bearing an Alkyne Chain
International audienc
Intramolecular Phospholithiation of alkynes and its application in synthesis of a novel phosphorus heterocycles
International audienc
Selective Substitution Reactions at the Phosphorus Atom of 1,3-Dienyl Phosphonates
International audienc
CobaltâCatalyzed Annulation of Benzimidates or NHâBenzaldimines with Ynamides: Synthesis of 1âAlkoxyâ and 1âAlkylâ3âAminoisoquinolines
International audienceAbstract Inexpensive cobaltâcatalyzed, pivalic acidâassisted oxidative CâH functionalization of benzimidates or NHâbenzaldimines with ynamides is presented, providing an access to 3âaminoisoquinoline derivatives. The procedure is compatible with various substrates featuring alkyl, alkoxy, acyl or halogen as substituents, heteroaryl structures, and diverse ynamides. The reaction has been scaled up, with subsequent transformation of the yielded products. Control experiments and mechanistic investigations corroborate the regioselectivity of this conversion, positioning the amine group proximal to the nitrogen atom in isoquinolines