Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Reexamination Certificate
2002-04-23
2003-12-02
Huang, Evelyn Mei (Department: 1625)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
C514S300000, C514S321000, C514S338000, C546S115000, C546S113000, C546S197000, C546S277400
Reexamination Certificate
active
06656950
ABSTRACT:
BACKGROUND OF THE INVENTION
This application claims priority from co-pending provisional application serial No. 60/286,301, filed on Apr. 25, 2001, the entire disclosure of which is hereby incorporated by reference.
Major depression is a serious health problem affecting more than 5% of the population, with a life-time prevalence of 15-20%.
Selective serotonin reuptake inhibitors have produced significant success in treating depression and related illnesses and have become among the most prescribed drugs. They nonetheless have a slow onset of action, often taking several weeks to produce their full therapeutic effect. Furthermore, they are effective in fewer than two-thirds of patients.
Serotonin selective reuptake inhibitors (SSRIs) are well known for the treatment of depression and other conditions. SSRIs work by blocking the neuronal reuptake of serotonin, thereby increasing the concentration of serotonin in the synaptic space, and thus increasing the activation of postsynaptic serotonin receptors.
However, although a single dose of an SSRI can inhibit the neuronal serotonin transporter which would be expected to increase synaptic serotonin, long-term treatment is required before clinical improvement is achieved.
It has been suggested that the SSRIs increase the serotonin levels in the vicinity of the serotonergic cell bodies and that the excess serotonin activates somatodendritic autoreceptors, 5HT
1A
receptors, causing a decrease in serotonin release in major forebrain areas. This negative feedback limits the increment of synaptic serotonin that can be induced by antidepressants.
A 5HT
1A
antagonist would limit the negative feedback and should improve the efficacy of the serotonin reuptake mechanism. (Perez, V., et al.,
The Lancet,
349:1594-1597 (1997)). Such a combination therapy would be expected to speed up the effect of the serotonin reuptake inhibitor.
Thus, it is highly desirable to provide improved compounds which both inhibit serotonin reuptake and which are antagonists of the 5HT
1A
receptor.
DESCRIPTION OF THE INVENTION
In accordance with this invention, there is provided a group of novel compounds of the formula:
wherein
R
1
is selected from hydrogen, hydroxy, halo, cyano, carboxamido, carboalkoxy of two to six carbon atoms, trifluoromethyl, alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 6 carbon atoms, alkanoyloxy of 2 to 6 carbon atoms, amino, mono- or di-alkylamino in which each alkyl group has 1 to 6 carbon atoms, alkanamido of 2 to 6 carbon atoms, or alkanesulfonamido of 1 to 6 carbon atoms;
R
2
, R
3
, R
4
and R
6
are independently selected from hydrogen, halo, cyano, trifluoromethyl, alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 6 carbon atoms, and alkanoyloxy of 2 to 6 carbon atoms; and
R
5
is hydrogen or alkyl of 1 to 6 carbon atoms;
X is CR
6
or N;
A dotted line represents an optional double bond;
(O) represents optional oxidation; and
n is an integer 0, 1 or 2;
or a pharmaceutically acceptable salt thereof.
In some preferred embodiments of the present invention R
1
is hydrogen, hydroxy, halo, cyano, trifluoromethyl, amino, mono- or di-alkylamino in which each alkyl group has 1 to 6 carbon atoms, alkyl of one to six carbon atoms or alkoxy of one to six carbon atoms. In still more preferred embodiments R
1
is hydrogen.
In other preferred embodiments of the invention R
2
, R
3
and R
4
are independently selected from hydrogen, halo, cyano, alkyl of one to six carbon atoms, or alkoxy of one to six carbon atoms. In still more preferred embodiments of the invention R
2
, R
3
and R
4
are independently selected from hydrogen, cyano or halogen.
In still other preferred embodiments of the invention R
3
is hydrogen or lower alkyl.
X is preferably CR
6
. When X is CR
6
, then R
6
is preferably hydrogen, halo, cyano, alkyl of one to six carbon atoms or alkoxy of one to six carbon atoms, and more preferably hydrogen, cyano or halogen.
Of the compounds of Formula I, the preferred members are those in which R
1
is attached to the 6-position of the 1,4-dioxino[2,3-b]pyridine and is hydrogen, hydroxy, halo, cyano, trifluoromethyl, amino, mono- or di-alkylamino in which each alkyl group has 1 to 6 carbon atoms, alkyl of one to six carbon atoms or alkoxy of one to six carbon atoms; R
2
, R
3
and R
4
are independently selected from hydrogen, halo, cyano, alkyl of one to six carbon atoms, or alkoxy of one to six carbon atoms; n is an integer 0 or 1; and R
5
, X, (O) and the dotted line are defined as above.
Most preferred are those examples in which R
1
is hydrogen, hydroxy or alkoxy of one to six carbon atoms, R
2
, R
3
and R
4
are independently selected from hydrogen, halo and cyano, R
5
is hydrogen, X is CR
6
, R
6
is hydrogen, halo, or cyano, n is 0, (O) is defined as above and the dotted line represents a double bond.
This invention relates to both the R and S stereoisomers of the 3-amino-methyl-1,4-dioxino[2,3-b]pyridines, as well as to mixtures of the R and S stereoisomers. Throughout this application, the name of the product of this invention, where the absolute configuration of the 3-aminomethyl-1,4-dioxino[2,3-b]pyridines is not indicated, is intended to embrace the individual R and S enantiomers as well as mixtures of the two. In some embodiments of the present invention the S stereoisomer is preferred.
Where a stereoisomer is preferred, it may, in some embodiments be provided substantially free of the corresponding enantiomer. Thus, an enantiomer substantially free of the corresponding enantiomer refers to a compound which is isolated or separated via separation techniques or prepared free of the corresponding enantiomer. Substantially free as used herein means that the compound is made up of a significantly greater proportion of one stereoisomer. In preferred embodiments the compound is made up of at least about 90% by weight of a preferred stereoisomer. In other embodiments of the invention, the compound is made up of at least about 99% by weight of a preferred stereoisomer. Preferred stereoisomers may be isolated from racemic mixtures by any method known to those skilled in the art, including high performance liquid chromatography (HPLC) and the formation and crystallization of chiral salts or prepared by methods described herein. See, for example, Jacques, et al.,
Enantiomers, Racemates and Resolutions
(Wiley Interscience, New York, 1981); Wilen, S. H., et al.,
Tetrahedron
33:2725 (1977); Eliel, E. L.
Stereochemistry of Carbon Compounds
(McGraw-Hill, NY, 1962); Wilen, S. H.
Tables of Resolving Agents and Optical Resolutions
p. 268 (E. L. Eliel, Ed., Univ. of Notre Dame Press, Notre Dame, Ind. 1972).
Furthermore, it is appreciated that, when R
1
is attached to the 6-position of the 1,4-dioxino[2,3-b]pyridine and is hydroxy, the molecule may exist as either the pyridone or pyridinol tautomer. The claims in this application or intended to embrace both tautomers, as well as mixtures of the two.
Alkyl as used herein refers to an aliphatic hydrocarbon chain and includes straight and branched chains such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neo-pentyl, n-hexyl, and isohexyl. Lower alkyl refers to alkyl having 1 to 3 carbon atoms.
Alkanamido as used herein refers to the group R—C(═O)—NH— where R is an alkyl group of 1 to 5 carbon atoms.
Alkanoyloxy as used herein refers to the group R—C(═O)—O— where R is an alkyl group of 1 to 5 carbon atoms.
Alkanesulfonamido as used herein refers to the group R—S(O)
2
—NH— where R is an alkyl group of 1 to 6 carbon atoms.
Alkoxy as used herein refers to the group R—O— where R is an alkyl group of 1 to 6 carbon atoms.
Carboxamido as used herein refers to the group —CO—NH
2.
Carboalkoxy as used herein refers to the group R—O—C(═O)— where R is an alkyl group of 1 to 5 carbon atoms.
Halogen (or halo) as used herein refers to chlorine, bromine, fluorine and iodine.
Pharmaceutically acceptable salts are those derived from such organic and inorganic acids as: acetic, lactic, citric, cinna
Stack Gary P.
Tran Megan
Huang Evelyn Mei
Woodcock & Washburn LLP
Wyeth
LandOfFree
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