Diphenyl-2-pyridylmethane

Diphenyl-2-pyridylmethane is a triaryl organic compound that has been used to selectively extract specific metal ions (as their thiocyanate complexes) into organic solvents. Its pharmacology is similar to the stimulant desoxypipradrol in which the pyridine ring is reduced to a piperidine and for which it is a chemical precursor.

Diphenyl-2-pyridylmethane
Names
IUPAC name
2-(Diphenylmethyl)pyridine
Other names
2-Benzhydrylpyridine
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.020.867
Properties
C18H15N
Molar mass 245.325 g·mol−1
Melting point 60-61 °C
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Preparation

Diphenyl-2-pyridylmethane was prepared by researchers at Ciba Pharmaceuticals (now Novartis) as the immediate precursor of desoxypipradrol, when they patented the latter as a psychomotor stimulant or narcoleptic.[1][2] Diphenyl acetonitrile was reacted with 2-bromopyridine, using sodamide as base and the resulting diphenyl-2-pyridylacetonitrile was hydrolysed and decarboxylated using potassium hydroxide in methanol.

Uses

Diphenyl-2-pyridylmethane behaves in coordination complexes with metal cations in the same way as pyridine, with the aromatic nitrogen potentially forming a bond to the metal. In this case, the bulky and lipophilic diphenylmethyl substituent means that the resulting complex may be appreciably soluble in organic solvents like chloroform and benzene. This ability to transfer metal cations from water into non-miscible solvents has been exploited to extract thiocyanate complexes for example of silver,[3] gold,[4] cobalt[5] and zinc;[6] in some cases in the presence of other metals which were retained in the aqueous phase.

Pharmacology

Pipradol and desoxypipradrol are norepinephrine-dopamine reuptake inhibitors that were not in practice widely used as drugs owing to their perceived potential for abuse. Although diphenyl-2-pyridylmethane is less potent than these molecules and its 4-pyridyl equivalent[7] it was nevertheless specifically included when the UK ACMD advised that this group of drugs be controlled as Class B.[8][9]

See also

References
  1. US patent 2820038, Hoffmann, K.; Heer, J. & Sury, E. et al., "2-Diphenylmethylpiperidine", issued 1958-01-14, assigned to Ciba Pharmaceutical Products
  2. Tripod, J.; Sury, E.; Hoffmann, K. (1954). "Zentralerregende Wirkung eines neuen Piperidinderivates". Experientia. 10 (6): 261–262. doi:10.1007/BF02157398. PMID 13183068. S2CID 20091456.
  3. Hasany, S. M.; Ali, A. (1990). "Preconcentration and separation of silver from neutron poisons and rare earths using diphenyl-2-pyridylmethane as an extractant". Journal of Radioanalytical and Nuclear Chemistry Articles. 139: 99–107. doi:10.1007/BF02060456. S2CID 97923942.
  4. Iqbal, M.; Ejaz, M.; Chaudhri, Shamim A.; Zamiruddin (1978). "The extraction of trace amounts of gold from different aqueous mineral acid solutions by diphenyl-2-pyridylmethane dissolved in chloroform". Journal of Radioanalytical Chemistry. 42 (2): 335–348. doi:10.1007/BF02519409. S2CID 95227795.
  5. Bhatti, M. S.; Shamasud-Zuha (1980). "Extraction of thiocyanate complexes of cobalt(II) by diphenyl-2-pyridylmethane in benzene from mineral acid solutions". Journal of Radioanalytical Chemistry. 59: 75–81. doi:10.1007/BF02516836. S2CID 94128359.
  6. Ejaz, M.; Shamasud-Zuha; Ahmad, Shujaat; Chaudhary, M. Saeed; Rashid, M. (1980). "Diphenyl(2-pyridyl)methane as a solvent for thiocyanate complexes of zinc in aqueous mineral acids". Mikrochimica Acta. 73 (1–2): 7–16. doi:10.1007/BF01197227. S2CID 92661161.
  7. Enyedy, Istvan J.; Sakamuri, Sukumar; Zaman, Wahiduz A.; Johnson, Kenneth M.; Wang, Shaomeng (2003). "Pharmacophore-Based discovery of substituted pyridines as novel dopamine transporter inhibitors". Bioorganic & Medicinal Chemistry Letters. 13 (3): 513–517. doi:10.1016/S0960-894X(02)00943-5. PMID 12565962.
  8. "Consideration of Desoxypipradrol (2-DPMP) and related pipradrol compounds" (PDF). UK Home Office. 2012-09-13. Retrieved 2020-08-25.
  9. "A Change to the Misuse of Drugs Act 1971: control of pipradrol-related compounds and phenazepam". UK Home Office. 7 Jun 2012. Retrieved 2020-08-25.
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