Alkyl 2-halocarboxylate

Keywords alkyl 2-halocarboxylate, unsaturated carboxylic ester, radical addition, lactone... 

Intramolecular alkylation of the amides of co-halocarboxylic acids, under phase-transfer catalysed conditions, provides an excellent route to lactams. The procedure... 

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-... 

The reaction of a -halocarboxylic acids with sodium nitrite has been used to synthesize ni-tromethane, nitroethane and nitropropane, although the reaction fails for higher nitroalkanes. " A number of other reactions have been reported which use nitrite anion as a nucleophile, including (1) reaction of alkyl halides with potassium nitrite in the presence of 18-crown-6, (2) reaction of alkyl halides with nitrite anion bound to amberlite resins, (3) synthesis of 2-nitroethanol from the acid-catalyzed ring opening of ethylene oxide with sodium nitrite, and (4) reaction of primary alkyl chlorides with sodium nitrite in the presence of sodium iodide. ... 

Several papers have dealt with electrophilic attack at the amide nitrogen of the unsubstituted benzisoselenazol-3(27T)-one. Alkylation using KOH and alkyl or allyl halide or halocarboxylic ester gave 2-substituted benzisoselenazol-3(27T)-ones <1991CZ135, 1989BSB395> and the reaction has synthetic value. 6-[Benzisoselenazol-3(27T)-one]-/3-cyclodextrin, designed as an artificial enzyme, was prepared by reaction of benzisoselenazol-3(2//)-one potassium salt with 6-iodo-/3-cyclodextrin (/3-CD-6-I) (Scheme 12) <2002CAR1309>. 

Comrie et al. prepared a number of 2,4-dioxoselenazolidine 2-alkyl-idenehydrazones (71) by the reaction of a-halocarboxylic acids with ketone and aldehyde selenosemicarbazones (70), [Eq. (18)], and Tsurkan et have recently made other derivatives of 71 by a similar method. 

Reaction with organoboranes.1 Brown has extended the reaction of ethyl bromo-acetate with trialkylboranes to ethyl dibromoacetate. If one equivalent of potassium r-butoxide is used, an a-halocarboxylic acid is obtained dialkylation is achieved by use of two equivalents of the base. Since the first reaction occurs readily at 0°, whereas the second requires a higher temperature (50°), two different alkyl groups... 

Other cases of alkylation of thiols were studied. Dithiols can be alkylated by halocarboxylic acids in high yields imder ultrasonic PTC conditions, but details are not readily available. ... 

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