Butyric 2-bromo-3-methyl

Automated parallel experiments were carried out to rapidly screen and optimize the reaction conditions for ATRP of methyl methacrylate (MMA) [34]. A set of 108 different reactions was designed for this purpose. Different initiators and different metal salts have been used, namely ethyl-2-bromo-tTo-butyrate (EBIB), methyl bromo propionate (MBP), (1-bromo ethyl) benzene (BEB), and p-toluene sulfonyl chloride (TsCl), and CuBr, CuCl, CuSCN, FeBr2, and FeCl2, respectively. 2,2 -Bipyridine and its derivatives were used as ligands. The overall reaction scheme and the structure of the used reagents are shown in Scheme 2. 

CsHsBrOj (R)-2-bromo-butyric acid methyl ester 114438-75-4 ... 

C5 H9 Br 02 4-bromo-butyric acid methyl ester 4897-84-1 RI Temp/C Lambda/nm Ref. 

Tetrahydrobenzo[6]thiophen-4-one (103) may be prepared from y-(2-thienyl)butyric acid by cyclization with phosphoric acid854 or by Friedel-Crafts cyclization of the corresponding acid chloride.194, 355.358 j s 5-methyl,357 2-ethyl,194 2-isopropyl,358 2- and 3-tert-butyl,359 2,3-dimethyl,360 2-ethyl-3-methyl,360 and 2-bromo 354 derivatives and diethyl 4,5,6,7-tetrahydrobenzo[6]thiophene-4,5-di-carboxylate861 may be prepared similarly. 4,5,6,7-Tetrahydrobenzo-[6]thiophen-7-one (104)357 362,863 and its 5- and 6-methyl 357 and 2-chloro 362 derivatives are obtained from the appropriately substituted y-(3-thienyl)butyric acid, A recent patent 364 describes the vapor phase cyclization of y-(2-thienyl)butyric acid to 103. Ketones (103 and 104) are useful intermediates for the synthesis of 4- and 7-substituted benzo[6]thiophenes, respectively their reactions are discussed in Section VI, B, 4. 

A solution of 34 ml of n-butyl lithium in 30 ml of anhydrous ether was cooled to -65°C under nitrogen and 5.3 ml of 3-methyl-2-bromothiophene in 10 ml anhydrous ether was added dropwise over a period of 10 min. The reaction mixture was stirred at -65°C for 1 h and 2.7 ml of ethyl 4-bromo-butyrate in 10 ml of anhydrous ether was added slowly. The reaction was stirred for 4 h while the temperature raised to -20°C, 20 ml water was added, and the mixture was stirred for 5 min after which the aqueous layer was removed. The ether layer was washed with 20 ml of water, and the combined aqueous phases were extracted with 50 ml of ether. The combined organic phases were dried over anhydrous sodium sulfate, which after evaporation yielded 9 g of 1-bromo-4,4-bis(3-methylthien-2-yl)but-3-ene as an oil. 

Secondary and tertiary alkyl bromides react with active zinc at ambient temperature. However, the reaction time for the oxidative addition can be shortened by heating the reaction mixture at reflux in THF. Methyl 3-bromo-butyrate gives the organozinc bromide intermediate upon reaction with active zinc and reacts with 2-cyclohexen-l-one to afford the 1,4-addition product (Protocol 6, Scheme 2.3).14... 

Using indolyl-based substrate analogs such as 5-bromo-4-chloro-3-indolyl-ace-tate, butyrate, or propionate (X-acetate, X-butyrate, and X-propionate) for esterases and using the p-rosaniline assay coupled with ethanol, butanol, or propanol for alcohol dehydrogenases we were able to isolate several hundred candidates in the first level of a hierarchical screen. An intermediate screen was then used to characterize and compare the esterase candidates. We used nitrophenyl and methyl-umbelliferyl derivatives to analyze esterase candidates and their preference for chain length. 

Methyl 2-bromobutyrate Butyric acid (70.4 g) is added to technical SOCl2 (112 g) during 75 min, with stirring, at room temperature, then the mixture is heated on a boiling water-bath for 30 min, after which the SOCl2 excess is distilled off. Bromine (135 g) is added to the residue at 80-90°, with stirring, and the whole is heated for 5 h on a boiling water-bath, then cooled. Methanol (46 ml) is added, and the solution is heated under reflux for 2 h. A small upper layer is formed and is separated in a separatory funnel and discarded. The remainder is distilled in a vacuum after a small forerun has been removed at 100° under atmospheric, pressure. The bromo ester (75-86%) has b.p. 70-75°/15 mm. 

Methyl butyrate Propyl acetate l-Bromo-3 -methylbutane... 

In addition, it has been shown that nucleophilic substitution reactions of mPEG-alk-oxides with ethyl 5-bromovalerate and ethyl 4-bromo-4-methyl butyrate, yield mPEG-ethyl valerate and mPEG-ethyl 2-methyl butyrate respectively, which upon hydrolysis should afford the corresponding free acids [81,82]. Presumably these reactions also give elimination products, as indicated for ethyl 3-bromopropionate. 

C7Hi3Br02 2-bromo-3-methyl-butyric acid ethyl ester 609-12-1... 

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