T Butyl bromoacetate

Section 10.20.5.4), in order to furnish the reduction product 47. In an additional reaction, it was found that treatment of the preformed sodium salt of fervenulone 16 with /< /t-butyl bromoacetate in DMF gave N-2-substituted analogue 48 together with a small amount of the O-alkylated adduct 49. 

Methyl l-thio-/3-D-galactopyranoside Acetal THF Amb. t-Butyl bromoacetate 0 65 0 198... 

Treatment of /3-thiolactone 327 with sodium hydride followed by methyl iodide, allyl iodide, or t-butyl bromoacetate gives the alkylated products, for example, 328... 

P-Amino acids. A method involving asymmetric alkylation of chiral N-acyloxazolidin-2-ones with t-butyl bromoacetate and saponification furnishes substituted succinic monoesters. On submission to degradation by (PhO)2PONj, properly protected P-amino acids are obtained. 

Diol 22 was also converted into diamine 54 which - after alleviation with te/t-butyl bromoacetate (to 55) and subsequent reduction of the... 

The amino group of 12 was monoalkylated with t-butyl bromoacetate in dimethylformamide in the presence of diisopropylethylamine (DIEA) to afford 13 (Figure 4). The latter was coiqiled to 6 using (1 -hydroxy-1 //-benzotriazolato-0)tris(A-mediylmedianaminato)pliosphorous hexafluorophosphate (BOP) in dimethylformamide in the presence of diisopropylethylamine. Subsequently, the reaction path followed that of complexes Ib-d. 

A dry 5(X)-mI flask equipped with a thermometer, pressure-equalizing dropping funnel, and magnetic stirrer is flushed with nitrogen and then maintained under a static pressure of the gas. The flask is charged with 50 ml of tetrahydrofuran and 13.3 ml (0.15 mole) of cyclopentene, and then is cooled in an ice bath. Conversion to tricyclo-pentylborane is achieved by dropwise addition of 25 ml of a 1 M solution of diborane (0.15 mole of hydride see Chapter 4, Section 1 for preparation) in tetrahydrofuran. The solution is stirred for 1 hour at 25° and again cooled in an ice bath, and 25 ml of dry t-butyl alcohol is added, followed by 5.5 ml (0.05 mole) of ethyl bromoacetate. Potassium t-butoxide in /-butyl alcohol (50 ml of a 1 M solution) is added over a period of 10 minutes. There is an immediate precipitation of potassium bromide. The reaction mixture is filtered from the potassium bromide and distilled. Ethyl cyclopentylacetate, bp 101730 mm, 1.4398, is obtained in about 75% yield. Similarly, the reaction can be applied to a variety of olefins including 2-butene, cyclohexene, and norbornene. 

The analogue, t-butyl methyl iminodicarboxylate 25, is obtained by the reaction of methanol with t-butyl oxamate (24) in the presence of lead tetraacetate. Its stable non-hygroscopic potassium salt is converted into alkyl derivatives 26 by the action of alkyl halides such as butyl bromide, allyl bromide, propargyl bromide and ethyl bromoacetate. The products are hydrolysed by trifluoroacetic acid to salts of primary amines, whereas... 

Methoxypolyethylene glycol and potassium t-butoxide were dissolved in t-butyl alcohol, stirred at 60°C, and then next treated with ethyl bromoacetate. The mixture was next stirred an additional 15 hours at between 80°C and 85°C, filtered, and... 

Moriwake, T. Reformatskii reaction. I. Condensation of ketones and tert-butyl bromoacetate by magnesium. J. Org. Chem. 1966, 31, 983-985. 

The best results are obtained with the use of alkali metal hydrides (NaH, KH) in THF, DME, or DMF. The reaction works well in THF or DME with activated halides such as ethyl bromoac-etate, ten-butyl bromoacetate, - ethyl 2-bromobutyratc, ethyl T-broniobulyrale.- (iodom-ethyl)trimethylstannane, " (iodomethyl)trimethylsilane, benzoyl bromide,- benzyl bro-mide, - farnesyl bromide,- " alkyl 4-bromocrotonates, l-(bromomethyl)naphtalene,- andN-bromomethylphthalimide but gives poor results with primary alkyl halides.- Primary and secondary alkyl halides, bromides and iodides (Scheme 8.16), react satisfactorily in dMF or DMSO, although bulky electrophiles give poor results. In DMSO the expected product is frequently contaminated by the dialkylation product. ... 

Metabolite C was first recognised by metabolic studies using [2- C]abscisic acid synthesised in the normal way from [2- C]bromoacetic ester. t-Butyl chromate oxidation of a-ionone provides an efficient synthesis of abscisic acid (Scheme 3). A large number of compounds related to abscisic acid have been synthesised to check their biological activity. In general, conventional synthetic methods were used. The Reformatsky reaction may be used as an alternative to the Wittig reaction for the synthesis of a-ionylidene acetic ester. 

McMahon, G., Wall, R., Nolan, K. and Diamond, D. (2002) Characterisation of the ester-substituted products of the reaction of p-t-butyl calix[4]arene and ethyl bromoacetate using LC-UV-MS and LC-DAD. Talanta, 57, 1119-1132. 

Following past precedent, preparation of the ring D component 152 originated from 2-methylcyclopentenone 1 via 150 prepared by 1 4 addition of vinyl magnesium bromide followed by addition of t-butylbromoacetate. Use of the t-butyl ester may have contributed to greater stereospecificity in the trans addition of the acetic ester side chain at C-2 relative to the C-3 vinyl group, since these substituents were >96% trans in 150. Lower stereospecificity was reported for addition of methylbromoacetate ( 88%) and ethyl bromoacetate ( 78%). Conversion of 150 to the methyl ester, ketalization with 2,2-dimethylpropane-... 

Rh6ne-Poulenc followed a corresponding strategy for Vitamin A acetate as weU. [76] ( )-4-Chloro-3-methyl-2-butenyl acetate is obtainable from isoprene in acetic acid and t-butyl hypochlorite. The corresponding bromoacetate is obtained using NBS. A disadvantage is the unsatisfactory yield, which stays usually below 50 %. [77] The elimination of benzenesulfinic acid in a homogeneous phase, with potassium alkoxides in methanol or pyridine, leads to a mixture of (aU E)- and (9Z)-isomers. This is remarkable, since besides the (aU )-actually... 

This reaction is sensitive to steric hindrance22-24. Moderately hindered alkyl groups, e.g., 1-methyl-1-propyl, 3-methyl-2-butyl, 3-hexyl, 2-c.vo-norbornyl and tm .s-2-methylcyclopentyl. are transferred, whereas the /rimv-2-mcthylcyclohcxyl group is not. As the substrate, chloroace-tonitrile is more reactive than ethyl bromoacetate. Reaction yields are in the range 45-66% (see Table 3). T he procedure also works with a mixture of 9-alkyl-9-borabicyclo[3.3.1]nonane and 9-alkyl-9-borabicyclo[4.2.1]nonane since these initial hydroboration products can be thermally isomerized solely to 9-alkyl-9-borabicyclo[3.3.1]nonane. 

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