Supplementary Data Design, synthesis and evaluation of molecularly targeted hypoxia-activated prodrugs Liam J. O Connor 1,2, Cindy Cazares-Körner 1,2,, Jaideep Saha 1,, Charles. G. Evans 1,2 Michael R. L. Stratford 2, Ester M. Hammond 2 * and Stuart J. Conway 1 * 1 Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK. 2 Cancer Research UK/MRC Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford, OX3 7DQ, UK. *To whom correspondence should be addressed: stuart.conway@chem.ox.ac.uk, telephone: +44 (0)1865 285 109, fax: +44 (0)1865 285 002. Table of contents General experimental procedures Experimental procedures References S2 S5 S11 S1
General experimental procedures 1 H MR spectra were recorded on Bruker AVC500, AVX500, DRX500 (500 MHz) or Bruker AV600 (600 MHz) using deuterochloroform (unless indicated otherwise) as a reference for the internal deuterium lock. The chemical shift data for each signal are given as δ H in units of parts per million (ppm) relative to tetramethylsilane (TMS) where δ H (TMS) = 0.00 ppm. The multiplicity of each signal is indicated by s (singlet); d (doublet); t (triplet); or q (quartet). The number of protons (n) for a given resonance signal is indicated by nh. Coupling constants (J) are quoted in Hz and are recorded to the nearest 0.1 Hz. Identical proton coupling constants (J) are averaged in each spectrum and reported to the nearest 0.1 Hz. The coupling constants are determined by analysis using Bruker TopSpin software. Spectra were assigned using COSY, HSQC and HMBC experiments as necessary. 13 C MR spectra were recorded on Bruker DRX500, AVC500, AVX600 or AV600 (126 MHz) spectrometers in the stated solvents, with broadband proton decoupling and an internal deuterium lock. The chemical shift data for each signal are given as δ C in units of parts per million (ppm) relative to tetramethylsilane (TMS) where δ C (TMS) = 0.00 ppm. The shift values of resonances are quoted to 1 decimal place, and were determined using Bruker TopSpin software. Mass spectra were acquired on a VG platform spectrometer and an Agilent 6120 spectrometer (low resolution). Electro-spray ionisation spectra were obtained on Micromass LCT Premier and Bruker MicroTOF spectrometers, operating in positive or negative mode as indicated, from solutions of OH or C. m/z values are reported in Daltons and followed by their percentage abundance in parentheses. lting points were determined using a Leica Galen III hot stage microscope and are uncorrected. Infrared spectra were obtained from neat samples as solids using a diamond ATR module. The spectra were recorded on a Bruker Tensor 27 spectrometer. Absorption maxima are S2
recorded in wavenumbers (cm -1 ), and reported as s (strong), m (medium), w (weak) or br (broad). Analytical thin layer chromatography (TLC) was carried out on normal phase rck silica gel 60 F 254 aluminium-supported chromatography sheets. Visualisation was by absorption of UV light (λ max 254 and 365 nm). Flash column chromatography was performed manually using Geduran Si 60, rck- Millipore (240-400 mesh) under a positive pressure of nitrogen. Petroleum ether refers to the fraction in the boiling point range 40 60 C. Compound purity for compounds was determined by elemental analysis. Elemental analysis was obtained at the Elemental Analysis Service, London tropolitan University, London. Elemental analysis was carried out in duplicate; average values are reported in Supporting Information. For all tested compounds, experimentally determined hydrogen, carbon, and nitrogen composition was within 0.4% of the expected value, implying a purity of >95%. S3
Ethyl 2-amino-1-methyl-1H-imidazole-5-carboxylate (13) EtO O 13 H 2 Pale yellow solid, mp 130-133 C (from H 2 O); TLC (CH 2 Cl 2 - OH, 9:1 v/v) R f = 0.42; 1 H MR (500 MHz, CDCl 3 ) δ H 7.44 (1H, s, CH), 4.41 (2H, s, H 2 ), 4.27 (2H, q, J 7.1, CH 2 CH 3 ), 3.68 (3H, s, CH 3 ), 1.34 (3H, t, J 7.1, CH 2 CH 3 ); 13 C MR (126 MHz, CDCl 3 )δ C 160.7, 152.1, 135.5, 119.1, 59.9, 30.6, 14.5; IR v max (solid)/cm -1 3126 (w), 1648 (s), 1246 (m), 1167 (s); HRMS m/z (ESI + ) [found (M+H) + 170.0919, C 7 H 11 3 O 2 requires M + 170.0924]; LRMS (m/z) (relative intensity) 170.1 ([M+H] +, 100 %); Analysis (calculated, found for C 7 H 11 3 O 2 ) C (35.1, 35.2); H (3.0, 2.8); (24.6, 24.4). These data are in good agreement with the literature values. 1 S4
Ethyl 1-methyl-2-nitro-1H-imidazole-5-carboxylate (14) CO 2 Et O 2 14 Yellow solid. mp 56-58 C (from CH 2 Cl 2 ) [lit. 2 mp 65-66 C]; TLC (CH 2 Cl 2 - OH, 9:1 v/v) R f = 0.85; 1 H MR (500 MHz, CDCl 3 ) δ H 7.76 (1H, s, CH), 4.40 (2H, q, J 7.3, CH 2 CH 3 ), 4.35 (3H, s, CH 3 ), 1.41 (3H, t, J 7.3, CH 2 CH 3 ); 13 C MR (500 MHz, CDCl 3 ) δ C 159.1, 134.6, 126.3, 61.8, 35.4, 14.1; IR v max (solid)/cm -1 2983, 1723, 1519, 1281, 1234; HRMS m/z (ESI ) [found (M+a) + 222.0480, C 7 H 9 3 ao 4 requires M + 222.0485]; LRMS (m/z) (relative intensity) 222.1 ([M+a] +, 100 %); Analysis (calculated, found for C 7 H 9 3 O 4 ) C (42.3, 42.2); H (4.4, 4.6); (21.0, 21.1). These data are in good agreement with the literature values. 2 S5
(1-thyl-2-nitro-1H-imidazol-5-yl)methanol (15) CH 2 OH O 2 15 Pale yellow crystals. mp 141-143 C (from EtOAc) [lit. 2 mp 142-144 C]; TLC (CH 2 Cl 2 - OH, 9:1 v/v) R f = 0.5; 1 H MR (500 MHz, DMSO-D 6 ) δ H 7.12 (1H, s, CH), 5.50 (1H, t, J 5.4, OH), 4.54 (2H, d, J 5.4, CH 2 ), 3.92 (3H, s, CH 3 ); 13 C MR (126 MHz, DMSO-D 6 ) δ C 146.7, 138.6, 126.5, 53.0, 34.1; IR v max (solid)/cm -1 3228 (br), 1490 (s), 1396 (s), 1038 (s); HRMS m/z (ES+) [found (M-H) 156.0412, C 5 H 6 3 O 3 requires M 156.0414]; LRMS (m/z) (relative intensity) 156.0 ([M-H], 100%); Analysis (calculated, found for C 5 H 7 3 O 3 ) C (38.2, 38.2); H (4.5, 4.5); (26.6, 26.7). These data are in good agreement with the literature values. 2 S6
5-(Chloromethyl)-1-methyl-2-nitro-1H-imidazole (16) O 2 16 Cl Pale yellow crystals. mp 87-90 C (from EtOAc) [lit. 3 mp 94-96 C]; TLC (petroleum ether - EtOAc, 1:1 v/v) R f = 0.4; 1 H MR (500 MHz, CDCl 3 ) δ H 7.17 (1H, s, CH), 4.63 (2H, s, CH 2 ), 4.06 (3H, s, CH 3 ); 13 C MR (126 MHz, CDCl 3 ) δ C 146.3, 132.9, 128.5, 34.2, 33.9; IR v max (solid) cm -1 : 1483 (s), 1360 (s); HRMS m/z (ESI + ) [found (M+a) + 198.0041, C 5 H 6 Cl 3 ao 2 requires M + 198.0041]; LRMS (m/z) (relative intensity) 198.1 ([M+a] +, 100%); Analysis (calculated, found for C 5 H 6 Cl 3 O 2 ) C (34.2, 34.3); H (3.4, 3.5); (23.9, 23.8); These data are in good agreement with the literature values. 3 S7
1-thyl-2-nitro-1H-imidazole-5-carboxylic acid (17) CO 2 H O 2 17 Off-white solid. mp 155-157 C (from CHCl 3 ) [lit. 2 mp 161-163 C]; TLC (AcOH-CH 2 Cl 2 - OH, 0.1:9:1 v/v) R f = 0.15; 1 H MR (500 MHz, OD-D 4 ) δ H 7.73 (1H, s, CH), 4.33 (3H, s, CH 3 ); 13 C MR (126 MHz, OD-D 4 ) δ C 161.6, 149.0, 134.8, 128.5, 35.8; IR v max (solid) cm -1 : 2924 (br), 1712 (s), 1497 (s), 1362 (s), 1236 (s); HRMS m/z (ESI ) [found; (M-H) 170.0207, C 5 H 4 3 O 4 requires M 170.0207]; LRMS (m/z) (relative intensity) 170.02 ([M-H], 68%); Analysis (calculated, found for C 5 H 5 3 O 4 ) C (35.1, 35.2); H (3.0, 2.8); (24.6, 24.4); These data are in good agreement with the literature values. 2 S8
1-thyl-2-nitro-1H-imidazole-5-carbaldehyde (18) CHO O 2 18 Colourless solid. mp 113-115 C (from acetone) [lit. 2 mp 114-115 C]; TLC (acetone - petroleum ether, 1:1 v/v) R f = 0.72; 1 H MR (500 MHz, CDCl 3 ) δ H 9.93 (1H, s, CHO), 7.82 (1H, s, CH), 4.36 (3H, s, CH 3 ); 13 C MR (126 MHz, CDCl 3 ) δ C 180.7, 148.6, 139.8, 132.7, 35.9; IR v max (solid)/cm -1 1681 (s), 1490 (s), 1327 (s); HRMS m/z (ESI + ) [found (M+OH+a) + 210.0484, C 6 H 9 3 ao 4 requires M + 210.0485]; LRMS (m/z) (relative intensity) 210.1 ([M+OH+a] +, 100 %). These data are in good agreement with the literature values. 2 S9
References 1 B. Cavalleri, R. Ballotta and G. Lancini, J. Heterocycl. Chem., 1972, 9, 979 984. 2 B. Cavalleri, R. Ballotta, V. Arioli and G. Lancini, J. d. Chem., 1973, 16, 557 560. 3 I. Parveen, D. P. aughton, W. Whish and M. D. Threadgill, Bioorg. d. Chem. Lett., 1999, 9, 2031 2036. S10