| Abstract |
The condensation of diethyl 4-hydroxy-4-methyl-6-oxo-2-(4-substitutedphenyl)-cyclohexane-1,3-dicarbo xylates and N -(2-chloropropyl)ethane-1,2-diamine leads to diethyl 1-(2-chloropropyl)-9-hydroxy-9-methyl-7-phenyl-1,4-diazaspiro[4.5]deca ne-6,8-dicarboxylate (2) and its para-substituted methyl (1), chloro (3), bromo (4), and nitro (5) derivatives with a new stereogenic center, which were fully characterized by elemental analysis, ESI-MS, IR, H-1 and C-13 NMR spectroscopies and X-ray single-crystal analysis (for 2). The condensation reaction is regioselective, only cyclohexanone carbonyl moiety undergoes the transformation, leaving the beta-keto ester carbonyls unreacted. Withing the compounds 1-5, the increase in the Hammett s sigma(p), related normal sigma(n)(p), inductive sigma(I), negative sigma(-)(p) and positive sigma(+)(p) polar conjugation and Taft s sigma(o)(p) substituent constants generally leads to the corresponding drift of delta(O-H) and delta(N-H) NMR chemical shifts to lower field. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved. |
