1- Methyl-3-carbomethoxypyridinium iodide

The reduction of l-methyl-2-carbomethoxypyridinium iodide (2, I ) with sodium amalgam leads to the pyridinyl radical dimer (2-2) (see sect. 4.1). The dimer is in equilibrium with the monomer (2 ) (K jssoc ca- 1.3-2.0 x 10 M by titration or EPR measurements) Dissociation of the dimer yields 2 , isolated via low temperature distillation (ca. 40-50 °C) with condensation at 77 K (Eq. 5). Dimerization occurs on warming the condensate above ca. 120 K. The spectroscopic properties of the radical 2" are determined with a new thin film spectroKopy apparatus, a device which dramatically simplifies experiments on stable radicals (S rt. 3.1.1). 

Hydrolysis. A solution of 5 g. of l-methyl-3-carbomethoxypyridinium iodide in 50 ml. of water was passed through a 2 x 15-cm. column of a strongly basic resin in... 

Reduct, of l-methyl-4-carbomethoxypyridinium iodide by Na-amalgam KAS CH3CN 298 fc = 5.07-IO- M- s- ... 

An aq. soln. of l-methyl-3-carbomethoxypyridinium iodide passed through a column of Dowex-1 (OH form), a strong base ion exchange resin, and eluted with water trigonelline. Y 87.4%. F. e. s. E. M. Kosower and J. W. Patton, J. Org. Ghem. 26, 1318 (1961). 

A calculated transition energy used to assess the polarity of a solvent. The solvent ionizing capability directly affects the position of a peak, easily measured, in the ultraviolet region of the spectrum of the complex of an iodide ion with 2-methyl- or l-ethyl-4-carbomethoxypyridinium ion. Water has a Z value of 94.6, ethanol has a value of 79.6, dimethyl sulfoxide s value is 71.1, and benzene has a value of 54. A similar polarity scale, known as x(30) values, is related to the Z value scale Z = 1.41 t(30) -E 6.92. See Solvent Effects... 

---