Boronic chromatography

Preparation of PAH-DNA adduct digestion labelling of adduct by 5p-postlabelling separation of steroisomers by immobilized boronate chromatography... 

Antiserum - protein A agarose (immobilized antibody for boronate chromatography)... 

Fig. 1. (left) Identification of the immunoprecipitated enzyme after gel electrophoresis and autoradiography. This experiment was designed to test die specificity of the immuno-assay using either the free or immobilized antibody. Lane 1 shows total P S]-labelled enzyme obtained using the immobilized antibody lane 2, unmodified enzyme obtained after boronate chromatography lane 3, identical to lane 1 except that free antibody was used and lane 4, pre-immune serum control for lane 3. 

R. P. Singhal, R. K. Bajaj, C. M. Buess, D. B. Smoll and V. N. Vakha-ria, Reversed-phase boronate chromatography for the separation of 0-methylribose nucleosides and aminoacyl-tRNAs, Anal. Biochem., 1980,109(1), 1-11. 

A. M. Azevedo, A. G. Gomes, L. Borlido, I. F. Santos, D. M. Prazeres and M. R. Aires-Barros, Capture of human monoclonal antibodies from a clarified cell culture supernatant by phenyl boronate chromatography, /. Mol Recognit., 2010, 23(6), 569-576. 

Lau, H. H. Baird, W. M. (1994). Separation and characterization of post-labeled DNA adducts of stereoisomers of benzo(a)pyrene-7,8-diol-9,10-epoxide by immobilized boronate chromatography and HPLC analysis. Carcinogenesis, 15,907-915. 

Conversion to acetates, trifluoroacetates (178), butyl boronates (179) trimethylsilyl derivatives, or cycHc acetals offers a means both for identifying individual compounds and for separating mixtures of polyols, chiefly by gas—Hquid chromatography (glc). Thus, sorbitol in bakery products is converted to the hexaacetate, separated, and determined by glc using a flame ionisation detector (180) aqueous solutions of sorbitol and mannitol are similarly separated and determined (181). Sorbitol may be identified by formation of its monobensylidene derivative (182) and mannitol by conversion to its hexaacetate (183). 

Homoallyl alcohol (3) Metalation of (E) butene (1 05 equiv) with n BuLI (t equiv) and KOtBu (1 equiv) in THF at SO C for 15 mm followed by treatment of (E)-crotyl potassum salt with B(OiPr)3 at 79°C gave after quenching with 1 N HCI and extraction with EtjO containing 1 equiv of diisopropyl tartarate. the crotyl boronate 2 A solution of decanall (156 mg 1 mmol) was added to a toluene solution of 2 (1 1 15 equiv) (0 2 M) at 78 C containing 4A molecular sieves (15-20 mg/L) After 3 h at -78°1 N NaOH was added, followed by extraction and chromatography to afford 208 mg of 3 (90%), anti syn 99 1... 

Esterification is readily achieved in THF in the presence of a dehydrating agent. The boronate is stable to chromatography, has good stability to 2 M TEA/ CH2CI2, but is not stable to aqueous 1 M NaOH. Cleavage is also achieved by hydrogenolysis. ... 

The oligomerization of cardanol with boron trifluoride etharate as the initiator was studied in detail by Antony et al. [171]. The reaction conditions were optimized by using gel permeation chromatography as 140°C with an initiator concentration of 1%. GPC data indicate conversion of all monoene, diene, and triene components into polymer except the saturated component, indicating participation of all the unsaturated components in polymerization. It is possible that the initiation of po-... 

Crude chloroform-methanol-water (30 60 8, v/v) extracts of immunostainedTLC bands were analyzed without further purification by nanoelectrospray low-energy mass spectrometry. The authors showed that this effective PLC/MS-joined procedure offers a wide range of applications for any carbohydrate-binding agents such as bacterial toxins, plant lectins, and others. Phenyl-boronic acid (PBA) immobilized on stationary support phases can be put to similar applications. This technology, named boronate affinity chromatography (BAC), consists of a chemical reaction of 1,2- and 1,3-diols with the bonded-phase PBA to form a stable... 

Liu (12) had reported that III could be conveniently separated from IV by selective thioketalization to V followed by purification by column chromatography. Accordingly, a mixture of approximately 70% III and 30% IV (60.9 g) was treated with 1,2-ethanedithlol (50 ml) and boron trifluoride etherate (6 ml). The crude product was distilled under reduced pressure to yield 45.1 g (54.4%, 77.6% based upon III as starting material) of crude V, sufficiently pure for the next step. Column chromatography of lower boiling impure fractions furnished the dithioketal VI (10% yield), unreacted IV, and additional V. ... 

The medicinal chemists subsequently discovered an improved route to racemic acid 9 that started with 2-bromo-2-cyclopente-l-one 11 (Scheme 7.2) [5]. Suzuki-Miyaura cross-coupling of 11 with 4-fluorophenyl boronic acid 12 provided 13 in 67% yield. Conjugate addition of cyanide furnished ketone 14 in 71% yield. Reduction of 14 with NaB H4 gave a 2.8 1 mixture of desired 15 and undesired 16 which were separated by silica gel chromatography. The observed diastereoselec-tivity with the cyano group was similar to ester 6. Hydrolysis of 15 with 5 M NaOH in MeOH gave racemic acid 9 in 91% yield, which was resolved as outlined in Scheme 7.1. 

Recently, iodobenzoates anchored onto an ionic liquid support (6.4) were coupled to various aryl boronic acids (6.5) in aqueous media using Pd(OAc)2 as the catalyst at 80°C to give the coupled product 6.6 (Scheme 6.3). Compounds 6.6 were purified simply by washing the reaction mixture with ether, which removed the unreacted starting materials and the side product 6.7 without the need of chromatography. Compounds 6.6 were then cleaved from the ionic liquid support... 

Typically, the boronic acid group is part of an aminophenyl boronic acid derivative, and this group has been used for bioconjugation and affinity chromatography purposes (Burnett et al., 1980 O Shannessy and Quarles, 1987). A common partner for a phenyl boronic acid group in bioconjugation is the salicylhydroxamic acid (SHA) group (Chapter 17, Section 3) (Reaction 59). 

Bergseid et al. (2000) also reported on the use of SHA-activated chromatography supports for the coupling of boronate-containing affinity ligands. In this case, immobilized RNase A was used to purify anti-RNase antibodies from antiserum samples. RNase A was modified with an NHS-PDBA crosslinker at a molar ratio of 100 1 (crosslinkenprotein), purified to remove excess crosslinker, and then coupled to an SHA-agarose support in 0.1 M sodium bicarbonate, pH 8.0. 

Pace, B., and Pace, N.R. (1980) The chromatography of RNA and oligoribonucleotides on boronate-substituted agarose and polyacrylamide. Anal. Biochem. 107, 128-135. 

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