C 13 H 16 N 2 O 2
g·mol 232.283 −1
Except where otherwise noted, data are given for materials in their
(at 25 °C [77 °F], 100 kPa).
Methylphenylpiracetam is a derivative of piracetam and a positive allosteric modulator of the sigma-1 receptor.   It differs from  phenylpiracetam by having a methyl group.
E1R is the (4 R,5 S) stereoisomer of methylphenylpiracetam.
The two R-configuration
enantiomers, i.e. (4 R,5 S) and (4 R,5 R), of methylphenylpiracetam are more active positive allosteric modulators of the sigma-1 receptor than the two S-configuration enantiomers, i.e. (4 S,5 R) and (4 S,5 S). 
σ 1R PAM effect %
erythro-(4 R,5 S) 222 ± 37
threo-(4 R,5 R) 191 ± 23
erythro-(4 S,5 R) 141 ± 40
threo-(4 S,5 S) 147 ± 31
E1R enhances cognition and has efficacy against
cholinergic dysfunction in mice without affecting locomotor activity. Pretreatment with E1R enhanced the σ  1R agonist PRE-084's stimulating effect and facilitated passive avoidance retention. It alleviated  scopolamine-induced cognitive impairment. The cognition enhancing activity of E1R is higher than that of (  R)-phenylpiracetam.
Because E1R had no effect on locomotor activity, it was found to be free of potential
motor side effects.
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Vavers E, Zvejniece L, Veinberg G, Svalbe B, Domracheva I, Vilskersts R, Dambrova M (2015). "Novel positive allosteric modulators of sigma-1 receptor". SpringerPlus. 4: P51. doi: 10.1186/2193-1801-4-S1-P51. PMC . 4797911 The R-configuration enantiomers of methylphenylpiracetam are more active positive allosteric modulators of Sigma-1 receptor than S-configuration enantiomers.
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Zvejniece, L; Vavers, E; Svalbe, B; Vilskersts, R; Domracheva, I; Vorona, M; Veinberg, G; Misane, I; Stonans, I; Kalvinsh, I; Dambrova, M (2014). "The cognition-enhancing activity of E1R, a novel positive allosteric modulator of sigma-1 receptors". British Journal of Pharmacology. 171 (3): 761–71. doi: 10.1111/bph.12506. PMC . 3969087 PMID 24490863.
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Veinberg, G; Vorona, M; Zvejniece, L; Vilskersts, R; Vavers, E; Liepinsh, E; Kazoka, H; Belyakov, S; Mishnev, A; Kuznecovs, J; Vikainis, S; Orlova, N; Lebedev, A; Ponomaryov, Y; Dambrova, M (2013). "Synthesis and biological evaluation of 2-(5-methyl-4-phenyl-2-oxopyrrolidin-1-yl)-acetamide stereoisomers as novel positive allosteric modulators of sigma-1 receptor". Bioorganic & Medicinal Chemistry. 21 (10): 2764–71. doi: 10.1016/j.bmc.2013.03.016. PMID 23582449.
Veinberg G, Vavers E, Orlova N, Kuznecovs J, Domracheva I, Vorona M, Zvejniece L, Dambrova M (2015). "Stereochemistry of phenylpiracetam and its methyl derivative: improvement of the pharmacological profile". Chemistry of Heterocyclic Compounds. 51 (7): 601–606. doi: 10.1007/s10593-015-1747-9. In conclusion, the obtained data demonstrated that E1R is the most active memory enhancing enantiomer of the 5-methyl-substituted phenylpiracetam homolog, and its cognition enhancing activity is higher than that of (R)-phenylpiracetam.