Salicylmethylecgonine

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Salicylmethylecgonine
Salicylecgonine.png
Identifiers
PubChem CID
ChemSpider
Chemical and physical data
Formula C17H21NO5
Molar mass 319.351 g/mol
3D model (Jmol)
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Salicylmethylecgonine, (2′-Hydroxycocaine) is a tropane derivative drug which is both a synthetic analogue and a possible active metabolite of cocaine.[1] Its potency in vitro is around 10x that of cocaine,[2] although it is only around three times more potent than cocaine when administered to mice (likely owing to it having a higher LogP: 2.89 than that of cocaine: 2.62)[3] Note however that the compound 2′-Acetoxycocaine would act as a prodrug to Salicylmethylecgonine in humans, and has a more efficient partition coefficient which would act as a delivery system and would circumvent this reason for a loss in potency. Salicylmethylecgonine also shows increased behavioral stimulation compared to cocaine similar to the phenyltropanes.[4] The hydroxy branch renders the molecule a QSAR of a 10-fold increase over cocaine in its binding potency for the dopamine transporter & a 52-fold enhanced affinity for the norepinephrine transporter. It also has a reduced selectivity for the serotonin transporter though only due to its greater increase at NET binding; it's SERT affinity being 4-fold increased compared to cocaine.[5] However, in overall binding affinity (not uptake inhibition) it displaces ligands better across the board than cocaine in all monoamine categories.

Binding comparison between cocaine and semi-synthetic derivative o-hydroxy-cocaine[4]
Compound DAT

[3H]WIN 35428

5-HTT

[3H]Paroxetine

NET

[3H]Nisoxetine

Selectivity

5-HTT/DAT

Selectivity

NET/DAT

Cocaine 249 ± 37 615 ± 120 2500 ± 70 2.5 10.0
2′(ortho)-hydroxycocaine 25 ± 4 143 ± 21 48 ± 2 5.7 1.9

Study of molecular modeling inferred that, in addition to intramolecular hydrogen bonding between the adjacent 3β-carbonyl and the 2′-OH ortho group of 185d (i.e. salicylmethylecgonine), that intermolecular hydrogen bonding between its hydroxy ortho substituent and the dopamine transporter was also possible; and was rationalized to be due to its nearness of where the nitrogen and oxygen atoms reside in the para-hydroxy of dopamine itself and its own intrinsic relation to DAT whereby that mutual hydroxyl functionality is mediated in both salicylmethylecgonine and dopamine in a similar manner. That is, at serine residue 359 on DAT, as the distance of the hydroxy to the bridge-nitrogen on salicylmethylecgonine is 7.96 Å (close to that of the distance between the p-OH & the NH2 atoms of dopamine, their distance apart being 7.83 Å). Which may play a role in this analogs increased behavioral stimulation over its parent compound cocaine. The meta-hydroxy group of dopamine, by contrast, has a distance of 6.38 Å from its nitrogen and is believed to engage with the 356 residue on DAT.[4]

See also[edit]

References[edit]

  1. ^ Singh S, Basmadjian GP, Avor K, Pouw B, Seale TW. A convenient synthesis of 2'- or 4'-hydroxycocaine. Synthetic Communications. 1997;27(22):4003-4012.
  2. ^ el-Moselhy TF, Avor KS, Basmadjian GP. 2'-substituted analogs of cocaine: synthesis and dopamine transporter binding potencies. Archiv der Pharmazie (Weinheim). 2001 Sep;334(8-9):275-8. PMID 11688137
  3. ^ Seale TW, Avor K, Singh S, Hall N, Chan HM, Basmadjian GP. 2'-Substitution of cocaine selectively enhances dopamine and norepinephrine transporter binding. Neuroreport. 10 November 1997;8(16):3571-5. PMID 9427328
  4. ^ a b c Chemistry, Design, and Structure-Activity Relationship of Cocaine Antagonists. Satendra Singh et al. Chem. Rev. 2000, 100. 925-1024. PubMed; Chemical Reviews (Impact Factor: 45.66). 04/2000; 100(3):925-1024 American Chemical Society; 2000 ISSN 0009-2665 ChemInform; May, 16th 2000, Volume 31, Issue 20, doi:10.1002/chin.200020238. Mirror hotlink.
  5. ^ Seale, TW; Avor, K; Singh, S; Hall, N; Chan, HM; Basmadjian, GP (1997). "2'-Substitution of cocaine selectively enhances dopamine and norepinephrine transporter binding". NeuroReport. 8 (16): 3571–5. doi:10.1097/00001756-199711100-00030. PMID 9427328.