O -Bromoacetate

Hydroxy-5-arylthiazoles, synthesis of from oxiranes and thioamides, 295 2-Hydroxy-4-arylthiazoles, synthesis of, from a-thiocyanatoacetophenones, 273 4-Hydroxy-2-(ot-cyano-ot-acetylmethylthia-zole, from of-cyano- -acetyl-thioace-tamide and ethyl-o-bromoacetate, 294 2-HydToxy-4,5-diroethyl-thiazole, synthesis of, 271... 

Beecham P-lactamase iiihibitoi BRL 42715 [102209-75-6] (89, R = Na), C IlgN O SNa (105). Lithium diphenylamide, a weaker base, was used to generate the anion of (88) which on sequential treatment with l-methyl-l,2,3-ttia2ole-4-carbaldehyde and acetic anhydride gives a mixture of diastereomers of the bromoacetate (90). Reductive elimination then provided the (Z)-penem (89, R = d5 Q [ OC15 -p) as major product which on Lewis acid mediated deprotection gave BRL 42715 (89, R = Na). 

In such combining forms as bromo-, cyano-, chloro-, nitro-, the connective 0 is to be used invariably (with the exception of a few well-established words such as acetamide, cyanamide) as, Chlorbenzol, chlorobenzene Chlor-essigsdure, chloroacetic acid. This usage is by no means universal, but those who can not reconcile themselves to such spellings as bromoacetic should at least avoid the German forms bromphenol, acetphenetidine, etc., and use the connecting o before consonants,... 

Correlation analyses of this type have also been carried out in connection with the kinetics of the reaction of arfha-substituted benzoate ions with para-substituted phenacyl bromides and of ortho-substituted benzoate ions with ethyl bromoacetate. In all cases it is possible to include o-S02Me among the basic set of well-behaved substituents. 

The Reformatsky reaction is related to both organometallic and aldol addition reactions and probably involves a cyclic TS. The Reformatsky reagent from /-butyl bromoacetate crystallizes as a dimer having both O—Zn (enolate-like) and C—Zn (organometallic-like) bonds (see Figure 7.5).165... 

Alkylation of 72 with ethyl bromoacetate using K2C03 as the base resulted in the O-, N-dialkylated derivative 105, whereas regioselective mono N-alkylation took place with ethyl iodide in the presence of NaH to give 106. Moreover, 72 smoothly added to methyl acrylate to give 107 (Scheme 7) <2003JHC789>. 

Compounds 161 and 162 were found to be unstable in basic, protic media, presumably due to the presence of the acidic hydrogen atom of the malonic ester. As a result, their synthetic utility is somewhat limited. It was, however, found possible to alkylate 162 with ethyl bromoacetate in the presence of sodium hydride,125 to give triethyl 1 - (2,3,5-tri-O-benzoyl- /3-d-ribofuranosyl) -1,1,2-ethanetricarboxylate (166). This product was obtained in 20% yield by treatment of 81... 

Carbohydrate lactones have been used as the carbonyl reagent in the Reformatsky reaction. Thus, 2,3 5,6-di-O-cyclohexylidene-D-mannono-1,4-lactone [44, obtained by oxidation of the mannofuranose derivative (49)] reacted with ethyl bromoacetate and zinc to give the protected 2-deoxy-3-octulosonic acid ethyl ester (45a) in 69% yield (50). Ketonic hydrolysis with potassium hydroxide in aqueous methanol, followed by acidification and heating, afforded the 1-deoxyheptulose derivative 45b. Similarly, starting from compound 44, the 1-C-substituted allyl and propar-gyl lactols were prepared on reaction with allyl or propaigyl bromides in the presence of zinc (51). 

Condensation of 2,3 5,6-di-O-isopropylidene-D-gulono-1,4-lactone (7a) with ethyl bromoacetate in the presence of zinc also gave the expected... 

Phosphitylation of inositol 3,4,5,6-tetra-O-benzyl myo-inositol by diben-zyl-iV,Ar-diisopropylphosphoroamidite gave the corresponding bis-diben-zylphosphite (step a). After 12 h at 80 °C the Arbuzov-Michaelis reaction with the excess of benzyl bromoacetate at 80 °C gave after 12 h the fully protected bis-l,2-diphosphonate (step b), which was totally deprotected by catalytic hydrogenolysis to give the desired product (step c). 

Sugar-derived a,(3-unsaturated lactones are relevant motifs considering their ability to act as functionalized substrates for a variety of transformations. Some of them are bioactive [218-222]. An early synthesis of the enantiomer of (+)-altholactone, a natural product with cytotoxic and antitumor activities (for a review on the bioactivity of styryUactones see [223, 224]), involves the preparation of a furanose-fused a,p-unsaturated 8-lactone intermediate 189 [225]. Starting from a a-D-xy/o-pentodialdofuranose derivative 187, aReformatsky reaction with ethyl bromoacetate introduces the carboxyhc side chain necessary for intramolecular lactonization (Scheme 46). 

Shalaby and co-workers <2002SG989> have reported that acetylation of dihydroxypyridazino[4,5-f]pyridazine 2 gives a mixture of O- and N-acetylated species (Equation 1), although treatment of 2 with ethyl bromoacetate in the presence of potassium carbonate gave only the 6,7-dialkylated product (39% yield). 

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. 

The reaction can be applied to allyl malonates. Alkylation of diallvl mal-onate (734) with bromoacetate and acetoxymethylation afford the mixed triester 735. Treatment of the tricster 735 with Pd catalyst affords allyl ethyl itaconate (736). In a similar way, o-methylene lactone and the lactam 737 can be prepared[462]. 

When 2,2-disubstituted 1,3-dioxolanes were employed, mono- or poly-chlorination of the side chain was observed on the carbon atom a to the acetal grouping. Incidentally, it should be noted thatN-bromo-succinimide, N-chlorosuccinimide, and trichlorotetrahydrotriazine-trione were found to be effective for the preparation of bromoacetates from O-ethylidene derivatives this might be useful when O-benzyli-dene derivatives are not readily available, or when a problem arises due to the fact thatO-benzoyl groups are, in general, more difficult to remove than O-acetyl groups. 

Ring closure of 2-aroylphenoxyacetic acids (244, R = H, R3 = aryl) is an unambiguous synthesis of 3-arylbenzofurans. A suitably o-hydroxylated benzophenone is condensed with ethyl bromoacetate ... 

The reaction of a-bromoacetals with trimethylsilylenolates catalyzed by titanium tetrachloride provides /3-alkoxy-y-bromoketones, which are useful furan precursors (Scheme 33) (75CL527). A new synthesis of acylfurans is exemplified by the formation of the 3-acetyl derivative (146) by heating the brdmoalkene (145) (78JOC4596). 2,2-Dimethyl-3(2//)-furanone (148) has been synthesized from 3-hydroxy-3-methylbutan-2-one treatment with sodium hydride and ethyl formate gave the hydroxymethylene derivative (147), which was cyclized and dehydrated to the furanone (148) with hydrochloric acid (Scheme 34) (71TL4891). O... 

Selenophenes (195) have been obtained by the condensation of phenacyl bromides with /S-aminovinyl selenoketones, readily obtained from chloroimmonium salts (194) (76S521). The reaction of o-methylselenobenzaldehyde with chloroacetone gives directly an excellent yield of 2-acetylbenzo[6]selenophene (196) (72BSF1643). However, the reaction with bromoacetic acid yields not only the corresponding 2-carboxylic acid (197), but also the self-condensation product (198). 

Ethyl bromoacetate (5.54 mL, 50 mmol) in THF (25 mL) was added dropwise to a cooled (ice bath) soln of amine 29 (llOmmol) in THF (25 mL). After stirring for 2.5 h at rt, the mixture was taken to dryness and the residue resuspended in E O. The predpitate was removed by filtration and washed with E O. The combined organic phase was taken to dryness and the residue purified by column chromatography (silica gel, Et20). 4M NaOH (2.5 mL) was added to the soln of /V-alkyl-Gly-OEt (10 mmol) in dioxane (35 mL) and MeOH (12.5 mL). After stirring for 30 min at rt, the mixture was taken to dryness. The residue was dissolved in H20 and the pH adjusted to 9-9.5 with coned HC1. To this mixture a soln of Fmoc-OSu (10 mmol) in MeCN (20 mL) was added in one portion and the pH maintained at 8.5-9.0 with TEA. The MeCN was removed and the residue added to 20% citric acid soln (60 mL). The soln was extracted with EtOAc (3 x 75 mL) and the combined organic layers were washed with H20 and brine, dried (Na2S04), and taken to dryness. The residual oil was recrystallized (EtOAc/hexane). 

In the nitrogen bag, 50.2 mg of [60]fullerene, ethyl bromoacetate (5 equiv.), zinc dust (20 equiv.) and the stainless-steel ball were placed in the capsule. The above mixture was vigorously agitated for 20 min at room temperature, quenched with 0.5 mL of CF3C02H in 20 mL of o-dichlorobenzene, and carefully separated by silica gel chromatography with hexane-toluene as the eluent to give the expected adduct 1 (17.2%) (62.5% based on consumed C60) together with 2 (0.8%), 3 (3.9%), 4 (1.8%) and unreacted C60 (72.5%). 

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