A-Bromopropionyl bromide

Block copolymers were synthesized by a combination of fipase-catalyzed polymerization and atom transfer radical polymerization (ATRE). " " At first, the polymerization of 10-hydroxydecanoic acid was carried out by using lipase CA as catalyst. The terminal hydroxy group was modified by the reaction with a-bromopropionyl bromide, followed by ATRP of styrene using CuCE2,2 -bipyridine as catalyst system to give the polyester-polystyrene block copolymer. Trichloromethyl-terminated poly(e-CL), which was synthesized by lipase CA-catalyzed polymerization with 2,2,2-trichloroethanol initiator, was used as initiator for ATRP of styrene. 

Although the formation of symmetric piperazine-2,5-diones is a well documented transformation (93AHC187), the unsymmetric -ones have been prepared from AAs or their amides with acyl halides, such as pyruvoyl chloride (81RTC73) and a-bromopropionyl bromide (91H923). 

Acetamido - 3 - hydroxy - 2 - methyl -1 4- benzisoxazine - 6-arsinic acid is isolated from 3-amino-5-acetamido-4-hydroxyphenyl-arsinic acid and a-bromopropionyl bromide it crystallises from boiling water in white prisms, decomposing at 265° C. It forms an amorphous magnesium salt. The S-acetamido-Z-hydroxy-i-ethyl-derivative crystallises from boiling water in colourless needles. 

Polystyrene-Woc -polysulfone-/ /oc -polystyrene and poly(butyl acrylate)-Woc -polysulfone-/ /oc -poly(butyl acrylate) triblock copolymers were prepared using a macroinitiator.214 The hydroxyl-terminated polysulfone was allowed to react with 2-bromopropionyl bromide, an atomic transfer radical polymerization (ATRP) initiator, in the presence of pyridine. The modified macroinitiator could initiate die styrene polymerization under controlled conditions. 

Bipyridine-centered triblock copolymers of the type BA-bpy-AB were prepared by a combination of ATRP and ROMP [159]. 4,4 -Bis(hydroxymelhyl)-2,2/-bipyridine was employed for the polymerization of lactic acid, LA or CL in the presence of Sn(Oct)2 in bulk at 130 and 110°C, respectively. The hydroxyl end groups were converted to tertiary or secondary bromo esters by reaction with 2-bromoisobutyryl bromide or 2-bromopropionyl bromide. The reaction yields were very high (> 80%) but not quantitative. These products were used as macroinitiators for the ATRP of MMA or tBuA in the presence of CuBr/HMTETA. 4,4/-bis(Chloromethyl)-2,2 -bipyridine was employed to promote the ATRP of MMA or styrene followed by the addition... 

After the development of catalyst-transfer condensation polymerization of polythiophene, the block copolymer of polythiophene and PMA could be prepared more easily. As mentioned above, the vinyl-terminated polythiophene was first prepared. The vinyl group was converted to the 2-hydroxyethyl group by hydroboration, followed by esterification with 2-bromopropionyl bromide to give a macroinitiator for ATRP (Scheme 101)... 

B-90 and B-91, respectively.390 Another route coupled with cationic ring-opening polymerizations is accomplished for polymer B-92 with the use of a hydroxyl-functionalized initiator with a C—Br terminal, where the OH group initiates the cationic polymerizations of 1,3-dioxepane in the presence of triflic acid.329 Polyethylene oxide)-based block copolymers B-93 are obtained by living anionic polymerization of ethylene oxide and the subsequent transformation of the hydroxyl terminal into a reactive C—Br terminal with 2-bromopropionyl bromide, followed by the copper-catalyzed radical polymerization of styrene.391... 

Non-living polymerization techniques can be combined with CRP methods to produce block copolymers. The first example of transforming a hydroxy functionality into an ATRP initiator was demonstrated by Gaynor and Matyjaszewski [223], who converted a polysulfone,prepared through the condensation polymerization of 4,4-difluorosulfone with an excess of bisphenol A, to an ATRP initiator by reaction with 2-bromopropionyl bromide for subsequent controlled polymerization reactions (cf. Scheme 26). The transformation proved to be quantitative and the macroinitiator (Mn=4030,Mw/Mn=1.5) was used for formation of triblock copolymers with St (Mn=10,700,Mw/Mn=l.l) or nBA (Mn=15,300,Mw/Mn=1.2) as shown in Fig. 31 [223]. DSC analysis provided evidence of the presence of two distinct blocks with Tg=153-159 °C (polysulfone) and 104 °C (pSt) or -41 °C (pBA). 

Hydrophilic pEG or pentaerythritol ethoxylate cores with hyperbranched polystyrene arms were prepared by reacting PEG or pentaerythritol ethoxylate with 2-bromopropionyl bromide followed by the ATRP of the macroinitiator and chloromethylstyrene to produce the amphiphilic hyperbranched polymer. Depending on the functionality of the macroinitiator, the products have either a dumbbell or 4-arm starburst structure. The dumbbell polymers tend to have... 

Cationically prepared pTHF can also contain a functional group capable of initiating an ATRP reaction, as shown by Kajiwara and Matyjaszewski [274]. Silver triflate in conjunction with 2-bromopropionyl bromide was used to initiate the ring-opening polymerization (ROP) of THF which, after quenching the re-... 

The field of densely grafted copolymers has received considerable attention in recent years. The materials (also called bottle-brush copolymers) contain a grafted chain at each repeat unit of the polymer backbone. As a result, the macromolecules adopt a more elongated conformation. Examples of brush copolymers have been provided within the context of ATRP [307-309]. Synthesis of the macroinitiator was achieved through one of two approaches. One method used conventional radical polymerization of 2-(2-bromopropionyloxy)ethyl acrylate in the presence of CBr4 to produce a macroinitiator with Mn=27,300, and a high polydispersity of Mw/Mn=2.3 (Scheme 46A) The alternative involved the ATRP of 2-trimethylsilyloxyethyl methacrylate followed by esterification of the protected alcohol with 2-bromopropionyl bromide. While synthetically more challenging, the latter method provided a macroinitiator of well-defined structure... 

Required amounts of anhydrous dichloromethane solutions of hydroxy functional reagents and triethylamine were placed into a flask and cooled to 0 °C in an ice/water bath, and then a dichloromethane solution of 2-bromopropionyl bromide was added dropwise with stirring over a period of 1 hour. After required time, a white precipitate of triethylammonium bromide salt was removed by filtration and the mixture was extracted consecutively with distilled water, NaHCOs (aq), and distilled water. The organic phase was dried over Na2S04 (anhydrous) and filtered. After the solvent evaporation, initiators were isolated by purification. 

Monoalkylketenes. Methylketene and ethylketene can be obtained in 60-65% yield by reaction of 2-bromopropionyl bromide and 2-bromobutyryl bromide in THF with zinc activated by treatment with hydrochloric acid (1, 1276) under reduced pressure (100 mm). The ketenes codistill with THF and are free from starting materials and zinc salts. The present method is a modification of Standinger s ketene synthesis, which gave only low yields of these ketenes. ... 

Bromo-o-propiono toluidine may be prepared by the condensation of a mole each of o-toluidine and 2-bromopropionyl bromide with the elimination of a mole of hydrogen bromide. This on further condensation with one mole of propyl amine yields the prilocaine base which on reaction with an equimolar amount of hydrochloric acid gives the official compound. 

Bifunctional polysulfones can be prepared by step-growth polymraization and end-capped using 2-bromopropionyl bromide (2). Triblocks arc thrai formed using ATRP with a CuBr/(dNbpy)2 catalyst and either styrene or i-butyl acrylate monom. ... 

An improved variant uses a bromopropionamide for the construction of the side-chain carboxylic acid this amide is simply accessible in two stages from cyclohexanone, salicylamide and bromopropionyl bromide. Then follows a Reformatzky reaction with remarkable diastereoselectivity under formal retention of the absolute configuration. [61] Chromatographic purification is not necessary. 

Yuan et al. [165] reported the synthesis of well-defined dendrimer-star, block-comb polymers by the combination of living ring-opening polymerization and atom transfer radical polymerization on the basis of a dendrimer polyester. Star-shaped dendrimer PCLs were synthesized by the bulk polymerization of e-caprolactone with a dendrimer initiator. The dendrimer PCLs tiien were converted into macroinitiators via esterification with 2-bromopropionyl bromide. And the star-block copolymer dendrimer poly(s-caprolactone)-block-poly(2-hydroxyethyl... 

After the development of catalyst-transfer condensation polymerization of polythiophene, the block copolymer of polythiophene and poly(alkyl acrylate) was prepared more easily. Vinyl-terminated polythiophene was first prepared. The vinyl group was converted to the 2-hydroxyethyl group by hydroboration, followed by esterification with 2-bromopropionyl bromide to give a macroinitiator for ATRP (Scheme 50) [142]. The allyl-terminated polythiophene was also converted to a macroinitiator for ATRP, which led to block copolymers of polythiophene and poly (aUcyl methacrylate) [143] or poly(acrylic acid) [144]. This allyl-terminated polythiophene has a bromine atom at the other end, which has an adverse effect on the purity of block copolymers prepared by ATRP. Hawker, Kim, and coworkers reported that replacement of the bromine with a phenyl group, followed by functionalization of the allyl group for the ATRP initiator unit, allowed access to narrower molecular weight distribution diblock copolymers of polythiophene and ATRP-derived vinyl block [145]. 

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