Geduran

Thin-layer chromatography (TLC) was performed using Merck-TLC Silica gel 60 F254 aluminum plates. The plates were developed in a mobile phase containing petroleum ether and ethyl acetate in ratio of 70:30. After drying, plates were revealed either with sulfuric vanillin, with a KMnO4 solution, or with a mixture of phosphomolybdic acid-cerium sulfate followed by heating using a heat gun, and read under UV light. Preparative thin-layer chromatography was performed using 20 X 20 cm silica gel 60 F254 Merck-glass plates, 0.5 mm thick. Merck Geduran® 40-63 µm silica gel was used for column chromatography. The crude material was purified by column chromatography using a step gradient of ethyl acetate in petroleum ether (0 to 10%, v/v) to afford hydroxylated pendimethalin compounds.

General Methods. All reactions were carried under argon atmosphere. DMF, acetone, THF, toluene, MeCN and acetic acid were used as received from Sigma Aldrich. CH 2 Cl 2 was dried using a dry solvent station GT S100 system. NMR Spectra (1H, 13C) were performed at 298 K. 1H (500 MHz or 300 MHz) and 13C (125 MHz) NMR chemical shifts are reported relative to internal TMS (δ = 0.00 ppm) or to residual protiated solvent. Data are presented as follows: chemical shift (ppm), multiplicity (s = singlet, d = doublet, t = triplet, q = quartet, sept = septet, m = multiplet, br = broad), coupling constant J (Hz) and integration. HRMS data were recorded on a microTOF spectrometer equipped with an orthogonal electrospray (ESI) interface. Thin layer chromatography was performed using Merck TLC silica gel 60 F254 aluminium sheets using petroleum ether/EtOAc or CH 2 Cl 2 /acetone as eluant and visualized using permanganate stain, ninhydrin stain, vanillin stain and/or UV light. Merck Geduran® 40-63 μm silica gel was used for column chromatography. Infrared spectra were reported in frequency of absorption using Alpha Bruker Optics spectrometer.