Infrared Study of the N—oh Group in Alpha and Beta Oximes

Abstract

The 0-H bending and N-0 stretching vibrations were studied in four pairs of isomeric oximes. A band a t 1265 cn1.-', characteristic of the solution spectra of the a oximes, is identified with the 0-H bending mode. Tentative assignments for the N-0 stretching vibration both in solid and solution spectra are advanced.The p isomers show a distinct shift of the band associated with the N-0 mode from about 950 cm.-' in the solid to about 930 cm.-l i n solution.The results of a recent investigation (13) of the infrared spectra of five pairs of isomeric oximes demonstrated that the most pronounced difference between the geometric isomers was the position of the band associated with the 0-H stretching vibration which occurred near 3250 cm.-I in the a and near 3115 cm.-I in the P oximes. Although the isomers could not be distinguished from one another on the basis of their frequencies in the 1300 cm.-1 and 900 cm.-I regions, tentatively attributed to the 0-H deformation and N-0 stretching modes, more detailed examination of these absorption bands seemed desirable in order to verify these assignments. This was attempted in the present study by examining the spectra of eight isomeric oximes a s Nujol mulls and in benzene and chloroforn~ solutions. The spectra of several N-and 0-methyl ethers as well as the sodium salts of some of the oximes were also obtained in order t o complenlent this work. E X P E R I M E N T A LThe preparation of the oximes has been described previously (13). T h e method of Goldschmidt and Kjellin (8) The sodium salts of a-benzaldoxime, a-p-nitro-, and a-p-cl~lorobenzaldoximes were prepared in the following manner. Slightly less than one millimole of sodium methoxide in methanol was added t o one nlillimok of the oxime. After standing for one to two minutes, the oxime salt was precipitated with copious amounts of anhydrous ether and filtered. T h e salt was washed several times with ether to remove unreacted oxime and was dried over phosphorous pentoxide. T h e infrared spectra de~nonstrated that the unreacted oximes had been completely removed from the salts. N o attempt was made to obtain analytically pure salts since they were used 'Manzrscript received M a y 17, 1954. Contribution jrom the

Synthesis and anticholinesterasic activity of some .alpha.-thiosubstituted O-(methylcarbamoyl)oximes

“…In the infrared spectrum of molecule 4a, done in a KBr pellet, the 0-H stretching band appears at 3160 cm-' for the isomer trans (phenyl and OH in trans position) and at 3200 cm-' for its cis homologue (molecule 3a). This change in frequencies of the absorption of the OH bond is in agreement with the observations of Palm andWerbin (1953,1954) who found this difference in the frequencies for oximes between E and Z forms.…”

Antibacterial Melamine Foams Decorated with in Situ Synthesized Silver Nanoparticles

“…This indicates that more H-bonds are formed on the ME foams . On the contrary, after the treatment, the increase of the intensity of the vibration band at 1289 cm –1 is observed, ascribed to the O–H in-plane bending in oxime (N–OH) functional groups . Such oximes can be formed by oxidation of primary amines (−NH 2 ) present in the pristine ME foam.…”

Photochemistry of N-nitroso-N-alkyl amino acids: a facile oxidative decarboxylation

“…6.8 ppm (18). The strong and broad ir absorptions at 3200-2700 cm-' also indicated the presence of intramolecular hydrogen bonding (19) which necessitated the Z-configuration. In addition, these compounds exhibited the characteristic C=N stretching mode at ca.…”

“…The peak at rt 2.5 min was shown to be composed of two components showing a shoulder on the decreasing side. The ascending side of the peak showed the mass peaks at mle (%): 161(38), 148(57), 120(37), 118 (17), 117 (19), 105(50), 91(60), 74(100), and 42(30); the tail-end of the peak showed those at mle (%): 251(13), 160 (14), 147(29), 146(86), 117(40), 91(100), 71 (13), and 56(81). The peak at rt 6.1 min was identified as N-forrnyl-3-phenylpropylamine 14 by the peak matching with an authentic sample and mass spectral pattern: 163 (M+, 34), 118(62), 117(52), 105 (18), 91(47), 77 (15), and 59(100).…”