A-Bromophenylacetic acid

The reaction of potassium 3-amino-4-oxo-3,4-dihydroquinazoline-2-thiolate 62 with a-bromophenylacetic acid 63 resulted in the formation of (3-amino-4-oxo-3,4-dihydroquinazolin-2-ylsulfanyl)-phenyl-acetic acid methyl ester 64 which on alkali treatment and subsequent acidification resulted in the synthesis of 2-phenyl- 1-thia-4,4a,9-triaza-anthracene-3,10-dione 65 <1999JCR(S)86>. Similarly, the reaction of potassium 3-amino-5,6-dimethyl-4-oxo-3,4,4a,7a-tetrahydrothieno[2,3- pyrimidine-2-thiolate 66 with a-bromo-ester 67 resulted in the formation of 2-(3-amino-5,6-dimethyl-4-oxo-3,4,4a,7a-tetrahydrothieno[2,3- / pyrimidin-2-ylsulfanyl)-propionic acid ethyl ester 68. Subsequent treatment with alkali followed by acidification resulted in the formation of 2,3,7-trimethyl-3a,9a-dihydro-l,8-dithia-4a,5,9-triazacyclopenta[ ]naphthalene-4,6-dione 69 <2000JHC1161>... 

Fig. 5. Inhibition mode of a-bromophenylacetic acid against AMDase-catalyzed decarboxylation. Lineweaver-Burk plot in the presence of the acid A, 100 pM B, 20 pM C, 0 pM...

As deduced from the DNA sequence of the gene, AMDase contains four cysteine residues. Since a-halocarboxylic acids are generally active alkylating agents there is a possibility that a-bromophenylacetic acid reacts with several cysteine residues of the enzyme. Therefore, we tried to clarify how many cysteine residues react with this inhibitor. It is well established that when p-chloromercuri-benzoate (PCMB) binds to a cysteine residue, the absorbance at 255 nm increases due to the formation of an aryl-Hg-S bond. Thus it is possible to estimate the number of free S-H residues of the enzyme by titration with PCMB solution (Fig. 6). When the native enzyme had reacted with PCMB, the absorbance at 255 nm increased by 0.025. On the other hand, when PCMB solution was added to the enzyme solution after the enzyme was incubated with a-bromophenyl-... 

Thienyl tellurolates also remove several different substituents such as acetoxy, mesyloxy, phenylthio and 2-thienyltelluro groups, as well as effect the reductive dehalo-genation of bromoacetanilide, and of a-haloacids (such as a-bromophenylacetic acid, a-bromo-l-naphthylacetic acid and a-chlorodiphenylacetic acid). ... 

Method C2 (typical catalytic procedure).A 5% solution of NaBH4 in 5% aqueous NaOH is added dropwise under N2 to a solution of a-bromophenylacetic acid (1.50 g, 7.0 mmol) and bis(2-thienyl) ditelluride (0.30 g, 0.71 mmol) in EtOH (40 mL) until the red colour of the ditelluride just disappears. At this point air is infioduced in the system to oxidize the catalyst back to the ditelluride. The mixture is then partitioned in ether/5% aqueous NaOH. The aqueous phase is separated, acidified with 2 M HCl and extracted with ether. The extract is dried (CaCl2) and evaporated to give phenylacetic acid (0.93 g (98%) m.p. 77°C). 

Anhydro-4-hydroxy-2,3,5-triphenyl-l,3-selenazolium hydroxide (65) is prepared by a multistep reaction selenobenzanilide (63) reacts with a -bromophenylacetic acid to give the a -seleno add (64) this acid readily cyclizes to the mesoionic selenazole (65), which upon reaction with DMAD affords an unstable adduct which by extrusion of selenium gives the pyridone diester (66 Scheme 23) (75CC617). 

Pyrrolo[2,l-4 [l,5]benzothiazocine 563a was prepared by alkylation of thiophenol 602 with a-bromophenylacetic acid 603 that furnished the carboxylic acid 604 (73% yield) which, by an intramolecular cyclization in presence of PCl5, yielded 563a (41% yield) (Scheme 121) <1997EJM241>. 

Mesoionic heterocycles 195 were synthesized from aminothienopyrimidinones 196, which were prepared in the reaction of 2-thioxothieno[2,3-bromophenylacetic acid, with acetic anhydride and triethylamine (1 1) (method a), or with AA -dicyclohexylcarbodiimide (DDC) in ethanol (method b) (2000JHC1161). 

Funke et al. used a-bromophenylacetic acid to prepare 2-phenyl-3,4-dihydro-1,4-benzothiazine (41) via a lithium aluminum hydride reduction of the l,4-benzothiazin-3-one intermediate.90 Similarly, chloroacetic acid gives products not substituted in the 2-position.65... 

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