US EPA

8360419 

Journal Article 

Catalysis of the Dedeuteration of Isobutyraldehyde-2-d by Linear Diamines Including 1-dimethylamino-8-amino-2-octyne, a Bifunctional Catalyst 

Hine, J; Lynn, JL; Jensen, JH; Schmalstieg, FC 

1973 

Yes 

Journal of the American Chemical Society
ISSN: 0002-7863
EISSN: 1520-5126 

95 

5 

1577-1581 

English 

10.1021/ja00786a036 

The catalytic activity of monoprotonated diamines of the type Me2N(CH2)nNH2(n = 2-5) in the dedeuteration of isobutyraldehyde-2-d in water increases monotonically with n, i.e., with the basicity of the catalysts. In 50% aqueous methanol monoprotonated hexane-1,6-diamine, undecane-1,11-diamine, and dodecane-1,12-diamine are of about equal catalytic activity. None of the preceding diamines is believed to act as a bifunctional catalyst to a major extent. The catalytic activity of l-dimethylamino-8-amino-2-octyne (2) was studied in water under conditions where it existed in the monoprotonated and the diprotonated forms to comparable extents. The term in the kinetic equation that was first order in monoprotonated diamine and first order in isobutyraldehyde-2-d was about 7.7 times as large as would be expected, from the catalytic activities of 3-dimethylaminopropyne and l-dimethylamino-2-butyne and other observations, in the absence of bifunctional catalysis. Therefore, the monoprotonated diamine is believed to act largely as a bifunctional catalyst by using its primary amino group to transform the aldehyde to an iminium ion and then removing the deuterium atom of the iminium ion internally by attack of the dimethylamino group. Compound 2 has an advantage over the four ω-dimethylaminoalkylamines that were studied in that it is long enough for its dimethylamino group to reach the deuterium atom in the trans isomer of the intermediate iminium ion. © 1973, American Chemical Society. All rights reserved.