OSA's Digital Library

Applied Spectroscopy

Applied Spectroscopy


  • Vol. 42, Iss. 2 — Feb. 1, 1988
  • pp: 236–242

Vibrational Spectroscopic Analysis of Minoxidil (2,4-Diamino-6-Piperidinopyrimidine-3-Oxide) and Related Analogs

R. S. Chao, T. J. Thamann, and K. C. Vail

Applied Spectroscopy, Vol. 42, Issue 2, pp. 236-242 (1988)

View Full Text Article

Acrobat PDF (751 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

  • Export Citation/Save Click for help


Tentative vibrational assignments for 2,4-diamino-6-piperidinopyrimidine-3-oxide (minoxidil) between 4000 and 600 cm−1 have been made. Complementary infrared and Raman studies indicate that the two amino groups of minoxidil are not equivalent in the solid state. One of them is a free amino group, while the other is hydrogen bonded to the N-oxide. Vibrational spectroscopic analyses of minoxidil in different molecular environments, such as in polar solvents, aprotic solvents, and deuterium oxide, as well as in the pH = 1.5-12.5 range, have been performed to probe the structural variations generated by these conditions. Spectral comparison of minoxidil and its derivatives reveals that most spectral changes involve the amino and N-oxide functional groups. For instance, the N-oxide stretching vibration occurs at 1210 cm−1 in the solid state, but it shifts to 1193 cm−1 in polar solvents.  The amino hydrogens of minoxidil and desoxyminoxidil (2,4-diamino-6-piperidinopyrimidine) are readily exchanged with deuterium, as reflected in the ND2 stretching region (2600-2300 cm−1) in the infrared spectra of deuterated crystalline minoxidil and desoxyminoxidil. The similarity of band contours in the NH2 stretching region suggests that there are no structural alterations on deuteration for either minoxidil or desoxyminoxidil.

R. S. Chao, T. J. Thamann, and K. C. Vail, "Vibrational Spectroscopic Analysis of Minoxidil (2,4-Diamino-6-Piperidinopyrimidine-3-Oxide) and Related Analogs," Appl. Spectrosc. 42, 236-242 (1988)

Sort:  Journal  |  Reset


References are not available for this paper.

Cited By

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited