Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Ester doai
Reexamination Certificate
1997-05-30
2001-02-20
Raymond, Richard L. (Department: 1624)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Ester doai
C514S114000, C514S538000, C514S539000, C514S561000, C514S576000, C514S620000, C558S166000, C558S390000, C560S012000, C560S013000, C560S017000, C560S021000, C562S016000, C564S164000, C564S165000, C564S306000, C564S316000, C564S317000, C564S319000, C564S320000, C564S322000
Reexamination Certificate
active
06191165
ABSTRACT:
The present invention relates to a class of substituted amines, pharmaceutical compositions and methods of treating neurological and neuropsychiatric disorders.
Synaptic transmission is a complex form of intercellular communication that involves a considerable array of specialized structures in both the pre- and post-synaptic neuron. High-affinity neurotransmitter transporters are one such component, located on the pre-synaptic terminal and surrounding glial cells (Kanner and Schuldiner,
CRC Critical Reviews in Biochemistry,
22, 1032 (1987)). Transporters sequester neurotransmitter from the synapse, thereby regulating the concentration of neurotransmitter in the synapse, as well as its duration therein, which together influence the magnitude of synaptic transmission. Further, by preventing the spread of transmitter to neighboring synapses, transporters maintain the fidelity of synaptic transmission. Last, by sequestering released transmitter into the presynaptic terminal, transporters allow for transmitter reutilization.
Neurotransmitter transport is dependent on extracellular sodium and the voltage difference across the membrane; under conditions of intense neuronal firing, as, for example, during a seizure, transporters can function in reverse, releasing neurotransmitter in a calcium-independent non-exocytotic manner (Attwell et al.,
Neuron,
11, 401-407 (1993)). Pharmacologic modulation of neurotransmitter transporters thus provides a means for modifying synaptic activity, which provides useful therapy for the treatment of neurological and psychiatric disturbances.
The amino acid glycine is a major neurotransmitter in the mammalian central nervous system, functioning at both inhibitory and excitatory synapses. By nervous system, both the central and peripheral portions of the nervous system are intended. These distinct functions of glycine are mediated by two different types of receptor, each of which is associated with a different class of glycine transporter. The inhibitory actions of glycine are mediated by glycine receptors that are sensitive to the convulsant alkaloid strychnine, and are thus referred to as “strychnine-sensitive.” Such receptors contain an intrinsic chloride channel that is opened upon binding of glycine to the receptor, by increasing chloride conductance, the threshold for firing of an action potential is increased. Strychnine-sensitive glycine receptors are found predominantly in the spinal cord and brainstem, and pharmacological agents that enhance the activation of such receptors will thus increase inhibitory neurotransmission in these regions.
Glycine functions in excitatory transmission by modulating the actions of glutamate, the major excitatory neurotransmitter in the central nervous system. See Johnson and Ascher,
Nature,
325, 529-531 (1987); Fletcher et al.,
Glycine Transmission,
(Otterson and Storm-Mathisen, eds., 1990), pp. 193-219. Specifically, glycine is an obligatory co-agonist at the class of glutamate receptor termed N-methyl-D-aspartate (NMDA) receptor. Activation of NMDA receptors increases sodium and calcium conductance, which depolarizes the neuron, thereby increasing the likelihood that it will fire an action potential. NMDA receptors are widely distributed throughout the brain, with a particularly high density in the cerebral cortex and hippocampal formation.
Molecular cloning has revealed the existence in mammalian brains of two classes of glycine transporters, termed GlyT-1 and GlyT-2. GlyT-1 is found predominantly in the forebrain, and its distribution corresponds to that of glutamatergic pathways and NMDA receptors (Smith, et al.,
Neuron
8, 927-935 (1992)). Molecular cloning has further revealed the existence of three variants of GlyT-1, termed GlyT-1a, GlyT-1b and GlyT-1c (Kim, et al.,
Molecular Pharmacology,
45, 608-617 (1994)), each of which displays a unique distribution in the brain and peripheral tissues. These variants arise by differential splicing and exon usage, and differ in their N-terminal regions. GlyT-2, in contrast, is found predominantly in the brain stem and spinal cord, and its distribution corresponds closely to that of strychnine-sensitive glycine receptors (Liu et al.,
J. Biological Chemistry,
268, 22802-22808 (1993); Jursky and Nelson,
J. Neurochemistry,
64, 1026-1033 (1995)). These data are consistent with the view that, by regulating the synaptic levels of glycine, GlyT-1 and GlyT-2 selectively influence the activity of NMDA receptors and strychnine-sensitive glycine receptors, respectively.
Compounds that inhibit or activate glycine transporters would thus be expected to alter receptor function, and provide therapeutic benefits in a variety of disease states. For example, inhibition of GlyT-2 can be used to diminish the activity of neurons having strychnine-sensitive glycine receptors via increasing synaptic levels of glycine, thus diminishing the transmission of pain-related (i.e., nociceptive) information in the spinal cord, which has been shown to be mediated by these receptors. Yaksh,
Pain,
37, 111-123 (1989). Additionally, enhancing inhibitory glycinergic transmission through strychnine-sensitive glycine receptors in the spinal cord can be used to decrease muscle hyperactivity, which is useful in treating diseases or conditions associated with increased muscle contraction, such as spasticity, myoclonus, and epilepsy (Truong et al.,
Movement Disorders,
3, 77-87 (1988); Becker,
FASEB J.,
4, 2767-2774 (1990)). Spasticity that can be treated via modulation of glycine receptors is associated with epilepsy, stroke, head trauma, multiple sclerosis, spinal cord injury, dystonia, and other conditions of illness and injury of the nervous system.
NMDA receptors are critically involved in memory and learning (Rison and Stanton,
Neurosci. Biobehav. Rev.,
19, 533-552 (1995); Danysz et al.,
Behavioral Pharmacol.,
6, 455-474 (1995)); and, furthermore, decreased function of NMDA-mediated neurotransmission appears to underlie, or contribute to, the symptoms of schizophrenia (Olney and Farber,
Archives General Psychiatry,
52, 998-1007 (1996). Thus, agents that inhibit GlyT-1 and thereby increase glycine activation of NMDA receptors can be used as novel antipsychotics and anti-dementia agents, and to treat other diseases in which cognitive processes are impaired, such as attention deficit disorders and organic brain syndromes. Conversely, over-activation of NMDA receptors has been implicated in a number of disease states, in particular the neuronal death associated with stroke and possibly neurodegenerative diseases, such as Alzheimer's disease, multi-infarct dementia, AIDS dementia, Huntington's disease, Parkinson's disease, amyotrophic lateral sclerosis or other conditions in which neuronal cell death occurs, such as stroke or head trauma. Coyle & Puttfarcken,
Science,
262, 689-695 (1993); Lipton and Rosenberg,
New Engl. J. of Medicine,
330, 613-622 (1993); Choi,
Neuron,
1, 623-634 (1988). Thus, pharmacological agents that increase the activity of GlyT-1 will result in decreased glycine-activation of NMDA receptors, which activity can be used to treat these and related disease states. Similarly, drugs that directly block the glycine site on the NMDA receptors can be used to treat these and related disease states.
SUMMARY OF THE INVENTION
By the present invention, a class of compounds has been identified that inhibit glycine transport via the GlyT-1 or GlyT-2 transporters, or are precursors, such as pro-drugs, to compounds that inhibit such transport, or are synthetic intermediates for preparing compounds that inhibit such transport. Thus, the invention provides a class of compounds formula:
or a pharmaceutically acceptable salt thereof,
wherein:
(1) X is nitrogen or carbon, and R
2
is not present when X is nitrogen;
(2) R
2
(a) is hydrogen, (C1-C6) alkyl, (C1-C6) alkoxy, cyano, (C2-C7) alkanoyl, aminocarbonyl, (C1-C6) alkylaminocarbonyl or dialkylaminocarbonyl wherein each alkyl is independently C1 to C6, (b) comprises (where R
1
is not aminoethylene, —O—R
8
Bell Stanley Charles
Borden Laurence A.
Ognyanov Vassil Iliya
Zhang Jing
Allelix Neuroscience Inc.
Coleman Brenda
Dechert
Raymond Richard L.
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