³¹P{¹H} NMR Studies of the Preparation of Dichlorotris(2,4,6-tribromophenoxy)phosphorane, Trichlorobis(2,4,6-tribromophenoxy)phosphorane, and Tetrachloro(2,4,6-tribromophenoxy)phosphorane, and their Nonoxidative Chlorination Reactions with Dimethyl Phosphonate

作者: Byrd, Houston ; Branham, Keith E. ; Gray, Gary M. ; Bharara, Prakash C.

Dichlorotris(2,4,6-tribromophenoxy)phosphorane can serve as a nonoxidative chlorinating agent for the conversion of secondary phosphites into chlorophosphites.However, the route reported for the synthesis of this material only gives a 22% yield, and the product contains significant impurities.To better understand the reasons for this poor yield, detailed ³¹P{¹H} NMR studies of the reactions of P pentachloride with one, two and three equivalent of 2,4,6-tribromophenol were carried out.These studies demonstrate that mixtures of the phosphoranes in which one, two and three of the chlorides are substituted by 2,4,6-tribromophenoxy groups were obtained even when a 3:1 ratio of the phenol to PCl₅ was used.Studies of the reactions of these mixtures with di-Me phosphonate indicate that all three phosphoranes are equally capable of transforming di-Me phosphonate into di-Me chlorophosphonite in quant. yield.The more highly substituted phosphoranes are very sensitive to H₂O and difficult to handle suggesting that the monosubstituted phosphorane is the reagent of choice.To demonstrate the synthetic utility of this nonoxidative chlorination reaction, W(CO)₅{P(OMe)₂Cl} was prepared in a one pot reaction involving the nonoxidative chlorination of di-Me phosphonate with the monosubstituted phosphorane followed by the reaction of the di-Me chlorophosphonite with W(CO)₅(MeCN).

2000-04-01·Polymer

Polycondensations of dimethyl phosphonate with diols: SEC and 1 P and 13 C NMR spectroscopic studies

作者: Bharara, P. C. ; Byrd, H. ; Branham, K. E. ; Mays, J. W. ; Bittinger, R. ; Gray, G. M. ; Farmer, B.

Polymeric phosphonate esters have a variety of potential applications.These polymers can be prepared by the polycondensations of di-Me phosphonate with certain diols.However, this method does not consistently yield high mol. weight polymers.NMR spectroscopy and size exclusion chromatog. studies demonstrate that low mol. weights result from Me group transfer from a Me phosphonate end group to an alc.The inactive phosphonic acid end groups formed by this reaction can be converted into reactive Me phosphonate end groups by treatment with diazomethane.This allows the preparation of polymers with number average mol. weights greater than 10⁴ Da.

项与 Absorbable Polymer Technologies, Inc. 相关的新闻（医药）

2020-12-06

·SYNAPSE

Evonik to acquire Birmingham-based LACTEL® Absorbable Polymers from DURECT Corporation

Essen, Germany. Evonik has signed an agreement to acquire the LACTEL® business of biodegradable polymers from DURECT Corporation (Nasdaq: DRRX) for USD 15m. The transaction is expected to close by Q1 2021 pending the satisfaction of certain customary closing conditions. An offer will be extended to each of the 15 employees of DURECT located in Birmingham, Alabama, which are associated with the LACTEL® business to transition to Evonik. “The acquisition of the Lactel® business will strengthen both our innovation growth field Healthcare Solutions and Evonik’s position as a globally leading CDMO for drug delivery solutions”, says Johann-Caspar Gammelin, Head of the Nutrition & Care Division of Evonik. The acquisition of the LACTEL® business marks a consequential step in the growth agenda of the life-science division Nutrition & Care. The LACTEL® business will benefit from fast-growing markets such as advanced drug delivery, biomaterials for tissue engineering, and the 3D printing of implantable medical devices. “It has been a pleasure working with the highly motivated and talented LACTEL® team. We have confidence that Evonik will apply its resources and commitment to excellence to enable the LACTEL® product line and supporting team members to thrive,” says James E. Brown, President and Chief Executive Officer of DURECT Corporation. With Evonik’s global reach, existing and new customers will benefit from tapping into Health Care’s twelve global laboratories staffed with formulation, application and regulatory experts to assist in bringing their products faster to the market. “The integration of the LACTEL® business into Evonik’s market-leading portfolio of functional excipients, biomaterials and integrated CDMO services will strengthen our position as a preferred development partner and solutions provider for pharmaceutical and medical device customers,” says Thomas Riermeier, Head of the Health Care business line. “By welcoming LACTEL® and members of their team into the Evonik family, we look forward to providing customers with even greater platform versatility as well as other value-adding services.” Poly(lactide-co-glycolide) (PLG or PLGA) polymers are widely used as a functional excipient to control the release of parenteral drug products. They are also utilized to control the biodegradation of implantable medical devices across various orthopedic, cardiovascular, wound healing and other applications. RESOMER® and LACTEL® are two of the most preferred brands of standard and custom PLGA polymers.

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2020-12-05

·SYNAPSE

Evonik Industries AG signed an agreement to acquire LACTEL Absorbable Polymer Product Line of DURECT Corporation for $15 million.

Evonik Industries AG (XTRA:EVK) signed an agreement to acquire LACTEL Absorbable Polymer Product Line of DURECT Corporation (NasdaqCM:DRRX) for $15 million on December 4, 2020. Under the terms of the agreement, Evonik agreed to pay DURECT the sum of $15 million in exchange for certain assets and liabilities associated with LACTEL product line based in Birmingham, Alabama, plus an additional potential payment based on full year EBITDAS results. The consideration is subject to adjustments based on the year-end net working capital. An offer will be extended to each of the 15 employees of DURECT located in Birmingham, Alabama, which are associated with the LACTEL® business to transition to Evonik. The transaction is subject to certain customary closing conditions and is expected to occur by the first quarter of 2021.

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