L-689,560 is a very potent antagonist at the glycine-NMDA site. The N-methyl-D-aspartate (NMDA) subtype of excitatorynamino acid receptor has been proved adequately that its relevant antagonists can reduce ischaemic brain damage (particularly in experimental models of focal cerebral ischaemia).

A potent antagonist at the glycine-NMDA receptor site

＞97%

Store at -20℃ for one year（Powder）；Store at 2-4℃ for two weeks；Store at -20℃ for six months after dissolution.

Solid

trans-2-Carboxy-5,7-dichloro-4-phenylaMinocarbonyl aMino-1,2,3,4-tetrahydroquinoline

White to yellow solid

Glutamate NMDA receptor: IC₅₀ = 4 nM (rat); Glutamate receptor subunit zeta 1: IC₅₀ = 4 nM (rat)

pK_a: 11.16 (Predicted), pK_b: 3.19 (Predicted)

Glutamate NMDA receptor: K_i= 2 nM (rat)

Soluble in DMSO (25 mM), ethanol (100 mM), and methanol.

L-689560 is described as one of the most potent NMDA antagonists and [4′-3H]-L-689560 has been thought to be a highly specific radioligand for the glycine site. In consistent with the 5,7-disubstituted kynurenates, the tetrahydroquinolines are selective antagonists of glycine site NMDA, L-689560 exhibiting at least 3 orders of magnitude selectivity versus the glutamate site.

MDL100748 with an ED50 of 83 mg kg-1 can prevent audiogenic seizures in susceptible mice after systemic injection. As a standard L689560, its subsequent analogues have been compared; the displacement of [3H] L689560 has often been used to displace that of [3H] glycine as an alternative assay. L701252, a quinones (the retention of a keto grouping at position 3), has been against L689560 binding (IC50 of 420 nM) and against seizures (ED50 of 4.1 mg kg-1) in DBA/2 mice. A group of sulfonamide analogues of kynurenic acid are also in active among the 2-quinolone series. Those of a series of 3,4-dihydroquinolones and tetrahydroquinolines with a nitrosubstituent at 3-position were selective antagonists at the NMDA receptor glycine site if they bore a bulky grouping in the position 4. The compound with no substitution at position 4 was proved to be one of the most effective broad-spectrum antagonists against NMDA and AMPA receptors.