2-bromopropionic acid ester

Caged bicyclic phosphates IVH could be conveniently synthesized by the condensation of phosphabicyclo[2.2.2]octane-l-one M21 or phosphabicyclo[2.2.2] octane-1-thione M22 and substituted phenoxypropionyl chlorides M20 in the presence of triethylamine as base (Scheme 5.10). The intermediates M20 could be easily obtained by the reaction of substituted phenoxypropionic acids M19 and thionyl chloride in high yields. The intermediates M19 were synthesized starting from substituted phenols and 2-bromopropionic acid ester. 4-(Hydroxymethyl)-2,6,7-trioxa-l-phosphabicyclo[2.2.2]octane-l-thione M22 could be prepared by treatment of the pentaerythritol with 1 equiv of phosphorus thiochloride in dioxane according to the method reported in the literature [65]. 

Substituted phenoxypropionic acids M19 could be synthesized starting from substituted phenols and 2-bromopropionic acid ester (Scheme 9.24). 

Zelinsky, N. A convenient preparation of a-bromopropionic acid ester. Ber. 1887, 20, 2026. 

It is important to carry out the esterification as rapidly as possible in order to cut down to a minimum the formation of ethyl hydracrylate, which takes place by the action of water on the (3-bromopropionic acid or ester an efficient condenser is therefore necessary. For the same reason it is necessary to remove all residual water from the mixture before adding the alcohol. 

As in the preparation of the /3-bromopropionic acid, bemiene must not be substituted for the carbon tetrachloride, as it has been found impossible to make a satisfactory separation of this solvent from the ester. 

Bromophenylurea, 31, 10 f)-Bromopheny] urea, 31, 8, 9 a-Bromopropionic acid, ethyl ester,... 

If an ester of o-bromopropionic acid were desired the appropriate alcohol would now be used, but as the acid itself is required, the bromide is decomposed by addition of one and one-third equivalents of water, the mixture being shaken under a reflux condenser, with a pot of ice close at hand, until homogeneous, and finally warmed for one-half hour on the water-bath. The solution is then cooled, treated with several volumes of ether, dried over sodium sulfate, and concentrated. When fractionated in vacuo the residue boils mainly at 1240 under a pressure of 18-19 mm. and solidifies in a freezing mixture, then melting at about 250. The acid should be protected from the moisture of the air. as it is quite hygroscopic. It is also a powerful skin irritant. The yield should be 60 per cent of the bromide used. 

Enholm [13] has also described the synthesis of soluble designer supports by the ring-opening metathesis polymerization (ROMP) of norbornyl derivatives. Reduction of norbornene-l-carboxaldehyde 88 to the corresponding alcohol 89, followed by treatment with either 2-bromopropionic acid or 2-bromo-2-phenylacetic acid in the presence of DCC, provided the esters 90 or 91 respectively (Scheme 19). Polymerization of 90 and 91 was carried out with Grubbs catalyst and halted after 25 s by capping with excess ethyl vinyl ether to give polymers 92 and 93 respectively. 

Thiones 349 react with chloroacetic acid, a-bromopropionic acid, or their esters to give cyclized products for which structure 350 was assigned (78MI1 81ACH197 83MI2) (Scheme 81). The cyclized product could also be represented by alternate structure 351. Data are inadequate to decide in favor of either. 

A number of syntheses of (V-hydroxy-a-amino acids and derivatives thereof have been reported. a-Bromocarboxylic acids or their r-butyl esters can be treated with hydroxylamine or 0-alkylated hydroxylamines to give the corresponding hydroxylamine derivatives. yV-Benzyloxy-t-alanine has been obtained by reaction of (/ )-a-bromopropionic acid with O-benzylhydroxylamine. But due to bromide exchange the optical yield was low. Anchimeric assistance of a suitable attached thio group can bring... 

Thiazolo[2,3-h]quinazolines [C S-C JV2-CeJ. The cycloaddition reaction of alkah-metal salts of 2-mercapto-4(3/f)-quinazolinones with 3-benzoyl-3-bromopropionic acids and esters gives acids (250) and lactones (251). ... 

The optical isomers of alanine have been prepared by amination of n- and v-a-bromopropionic acids. The latter have been prepared by the action of PC1, and acetyl chlo-nde on n-serine methyl ester hydrochloride (904), by tiie action of nitroqrl bromide on n-alanine (289), and by the resolution of nir -bromopropionic add (147,6S4-656,507, 845). The preparation of n-alanine by the action of yeast on nn-alanine has been described by Ehrlich (234). L-Alanine has been prepared by the actimi of takadiastase (408, 584) and n-amino add orddase (79, 229) obtained from sheep or hog kidneys. The last author (Behrmn) isolated 22 g. of nearly pure ir-alanine from the reaction products of 72 g. of on-alanine. The velodty of the oxidation of i>-alanine by o-amino add oxidase has been determined by Stadie and Zapp (7S2). 

EHsubstituted (—)-a-methyl-a-ethyl-]3-thiolactone (IX) was synthesized by Jerman and Fles [7 ] from (+)-methyl-ethylmalonic acid monoethyl ester (V), which was prepared by fractional crystallization of diastereomeric quinine salt for the (+)-antipode and cinchonidine salt for the (—)-antipode. Monoester (V) was converted to a-methyl-a-ethyl-/3-bromopropionic acid (VI) using essentially the method described by Sweeney and Casey [4] for the racemic compound. Optically active a-methyl-a-ethyl-j3-fiiiolactone (IX) was synthesized either via the dehydration of the /3-mercapto derivative (VII) or by debenzylation of the jS-benzyl-... 

The reaction of dihydropyrimidine-2(lH)-thione (propylenethiourea) 1 with a-halocarboxylic acids gives only the bicyclic thiazolo[3,2-a]pyrimidine. The most convenient procedme for the synthesis of 3,4-dihydropyrimidine-2(l//)-thiones (known as the Biginelli reaction) is based on one-pot three-component condensation of aldehydes with P-keto esters and thiomea. Thiazolopyrimidine derivatives (3, Scheme 1) were obtained by a simple one-pot condensation reaction of 1 and 2-bromopropionic acid (2, R3 = H, bromoacetic acid (2, R3 = H, CH3) imder microwave irradiation and conventional conditions [12, 13]. 

Ethyl a-bromopropionate. This preparation illustrates the facile bromination of an acid chloride (propionyl chloride) in the presence of red phosphorus, and the subsequent conversion of the bromoacid chloride into the ethyl ester by direct interaction with ethanol. 

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