(m/z): 270.66 (100, [M + H]+). Elemental analysis calc. (%)
for C14H14N4O2 (270.287): C, 62.21; H, 5.22; N, 20.73; found
C, 62.40; H, 5.38; N, 20.62.
NMR data of 3-methylxanthine (3MX) aggregates
See Table 3, Table 4 and Fig. 4.
Method B39. Compound 136 (0.900 g, 3.72 mmol) was
dissolved in water (12 mL) and 1 M sodium hydroxide
(4.5 mL, 1.2 equiv.) under sonication and warmed to effect
dissolution. After the addition of methyl iodide (0.527 g,
3.72 mmol, 1 equiv.), the reaction mixture was shaken for
2 h using a peptide shaker. The obtained heterogeneous
solution was diluted with water (500 mL) and extracted with
EtOAc (5 ꢂ 100 mL). The organic layer was dried (Na2SO4),
filtered, evaporated in vacuo and co-evaporated with MeCN
(3 ꢂ 100 mL). The crude product was purified by column
chromatography using the solvent system 5–20 v/v% EtOAc
in CH2Cl2 to give compounds 2 (0.300 g, 31.5%) and 3
(0.148 g, 14.7%), along with unreacted starting material 1
(0.483 g, 53.8%).
Acknowledgements
This study was supported by grants OTKA NK 73672, NK
´
68578, CK 77515, COST Action MP0802, TAMOP 4.2.1.B 09/
1/KONV, University of Szeged, HPC-Europa2, Free
University of Amsterdam and the SARA Supercomputing
Center. We also thank the Netherlands Organization for
Scientific Research (NWO-CW and NWO-NCF) and the
National Research School Combination-Catalysis (NRSC-C)
for financial support, and Mr. Istvan Mandity for his
´ ´
assistance with the H-Cubes flow reactor.
Notes and references
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c
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New J. Chem., 2011, 35, 476–482 481