- Dichloromeldrum's acid (DiCMA): A practical and green amine dichloroacetylation reagent
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Dichloromeldrum's acid is introduced as a bench-stable, nonvolatile reagent for the dichloroacetylation of anilines and alkyl amines to produce α,α-dichloroacetamides, which are important motifs for medicinal chemistry. Products are formed in good to excellent yields with reagent grade solvents, and, as the only byproducts are acetone and CO2, no column chromatography is required. Thus, this reagent is practical, efficient, and green for the dichloroacetylation of primary amines.
- Heard, David M.,Lennox, Alastair J.J.
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supporting information
p. 3368 - 3372
(2021/05/06)
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- Generation of antibodies to di- and trichloroacetylated proteins and immunochemical detection of protein adducts in rats treated with perchloroethene
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Antibodies directed against chemical specific protein modifications are valuable tools to detect and comparatively quantify protein modifications. Both Nε-(dichloroacetyl)-L-lysine and N(ε)(trichloroacety)]-L-lysine have been detected as modified amino acids in liver and kidneys of rats treated with perchloroethene (PER) after proteolysis. These protein modifications are formed by the interaction of reactive metabolites formed from PER with proteins. In this study we developed monospecific antibodies to dichloroacetylated and to trichloroacetylated amino acids to detect modified proteins in the target organs of PER toxicity. These antibodies were prepared by immunization of rabbits with modified keyhole limpet hemocyanin (KLH) coupled with either the dichloroacetyl or trichtoroacetyl moiety. Enzyme- linked immunosorbent assays (ELISA) indicated that the polyclonal rabbit sera recognized dichloroacetylated or trichloroacetylated rabbit serum albumin (RSA), but not unmodified protein. Therefore, we further purified rabbit antisera on either N(ε)-(dichloroacetyl)-L-lysine or N(ε)- (trichloroacetyl)-L-lysine immobilized to immunoaffinity columns to obtain monospecific antibodies. The potential of these antibodies in the detection of di- and trichloroacetylated proteins and their selectivity for the desired dichloroacetyl or trichloroacetyl group was demonstrated in competitive enzyme-linked immunosorbent assays with several structurally related compounds. Anti-dichloroacetyl (anti-DCA) antibody binding to dichloroacetylated RSA was inhibited by N(ε)-(dichloroacetyl)L-lysine with an IC50 value of 150 μM whereas inhibition by N(ε)-(monochloroacetyl)-L- lysine and N(ε)-(trichloroacetyl)-L-lysine showed an IC50 value of 100 mM. The binding of the antitrichloroacetyl (anti-TCA) antibody to trichloroacetylated RSA was inhibited by N(ε)-(dichloroacetyl)-L-lysine with an IC50 value of 80 mM. The inhibition by N(ε)-(trichloroacetyl)-L-lysine was again 3 orders of magnitude stronger resulting in an IC50 value of 90 μM. N(ε)-(acetyl)-L-lysine and unmodified RSA did not effect antibody binding to the chemically modified antigen. The antibodies were also successfully applied to detect modified proteins in subcellular fractions of liver and kidney from PER treated rats demonstrated in immunoblot. Protein adduct formation from different PER metabolism pathways was confirmed by the observation that the majority of dichloroacetylated proteins were located in kidney mitochondria and trichloroacetylated proteins were located in liver microsomes.
- Paehler, Axel,Birner, Gerhard,Parker, Jean,Dekant, Wolfgang
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p. 995 - 1004
(2007/10/03)
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