2 thiazoline 2 thiol

Ligand 1 (LacNAc; Galβ4GlcNAc) was obtained from Carbosynth (Compton, UK). The preparation of β-galactosidase from Bacillus circulans Biolacta^® was from Daiwa Kasei (Aichi, Japan). β-Alanine, 2,2′-azobisisobutyronitrile (AIBN), 2-cyanopropan-2-yl dithiobenzoate, 2-thiazoline-2-thiol (CTA), CuBr, methyl 3,5-dihydroxybenzoate, methyl-3,4,5-trihydroxybenzoate, N-Boc-ethylenediamine, and N,N-diisopropylethylamine (DIPEA) were obtained from Sigma-Aldrich (Prague, Czech Republic). Propargyl bromide was purchased from Acros Organics (Pardubice, Czech Republic), and trifluoroacetic acid (TFA) was acquired from Iris Biotech (Marktredwitz, Germany).

1,4-Dioxane, 2,2′-azobisisobutyronitrile (AIBN), 2-cyanopropan-2-yl dithiobenzoate (CTA-AIBN), 2-thiazoline-2-thiol, 2,4,6-trinitrobenzene-1-sulfonic acid (TNBSA), 3-azido-1-propylamine, 4,4′-azobis(4-cyanopentanoic acid) (ACVA), 4-cyano-4-(thiobenzoylthio)pentanoic acid (CTA-ACVA), dimethyl sulfoxide (DMSO), methacryloyl chloride, N,N-diisopropylethylamine (DIPEA), N,N-dimethylacetamide (DMA), phosphate buffered saline (phosphate buffer 0.01M and NaCl 0.154M, pH 7.4) (PBS), and t-butanol were purchased from Sigma-Aldrich (Prague, Czech Republic). 2,2′-Azobis(4-methoxy-2,4-dimethylvaleronitrile) (V-70) was from Fujifilm Wako Chemicals Europe (Neuss, Germany). 3-Amino-1-(11,12-didehydrodibenzo[b,f]azocin-5(6H)-yl)propan-1-one (DBCO-NH₂) was from Click Chemistry Tools (Scottsdale, AZ, USA). N-(3-tert-butoxycarbonyl-aminopropyl)methacrylamide (APMA-Boc) was purchased from Polysciences, Inc. (Warrington, PA, USA), and 1-aminopropan-2-ol was from TCI Europe (Zwijndrecht, Belgium). All solvents and chemicals were of analytical grade.

Zinc nitrate hexahydrate (>99%) was purchased from Fluka. Gallium oxide (99.999%) and chromium (III) nitrate non-ahydrate (99.99%) were purchased from Alfa Aesar. (3-Aminopropyl)-triethoxysilane (99%) was obtained from Sigma-Aldrich. Dimethylformamide (>99.9%) was purchased from SDS. Alpha-methoxy-omega-N-hydroxysuccinimide poly(ethylene glycol) M_W 5.000 Dalton was bought from Iris Biotech GmbH. 1-Aminopropan-2-ol, methacryloyl chloride, tert-butanol (t-BuOH), dimethyl sulfoxide (DMSO), diethyl ether, ethyl acetate, acetone, methanol (MeOH), dimethylacetamide (DMA), dichloromethane (DCM), 2,2′azobis(isobutyronitrile) (AIBN), 4-cyano-4-(ethylthiocarbonothioylthio) pentanoic acid, 2-thiazoline-2-thiol, N-ethyl-N′-(3-dimethyl aminopropyl)carbodiimide hydrochloride were purchased from Merck-Sigma-Aldrich (Germany). Azo initiator V-70 was purchased from Wako Chemicals (Japan).