Various central nervous system disorders such as anxiety, depression, motor disorders, etc., are believed to involve a disturbance of the neurotransmitter 5-hydroxytryptamine (5-HT) or serotonin. Serotonin is localized in the central and peripheral nervous systems and is known to affect many types of conditions including psychiatric disorders, motor activity, feeding behavior, sexual activity, and neuroendocrine regulation among others. The effects of serotonin are regulated by the various 5-HT receptor subtypes. Known 5-HT receptors include the 5-HT1 family (e.g. 5-HT1A), the 5-HT2 family (e.g. 5-HT2A), 5-HT3, 5-HT4, 5-HT5, 5-HT6 and 5-HT7 subtypes.
The recently identified human 5-hydroxytryptamine-6 (5-HT6) receptor subtype has been cloned, and the extensive distribution of its mRNA has been reported. Highest levels of 5-HT6 receptor mRNA have been observed in the olfactory tubercle, the striatum, nucleus accumbens, dentate gyrus and CA1, CA2 and CA3 regions of the hippocampus. Lower levels of 5-HT6 receptor mRNA are seen in the granular layer of the cerebellum, several diencephalic nuclei, amygdala and in the cortex. Northern blots have revealed that 5-HT6 receptor mRNA appears to be exclusively present in the brain, with little evidence for its presence in peripheral tissues. The high affinity of a number of antipsychotic agents for the 5-HT6 receptor, in addition to its mRNA localization in striatum, olfactory tubercle and nucleus accumbens suggests that some of the clinical actions of these compounds may be mediated through this receptor. Therefore, 5-HT6 receptor ligands are believed to be of potential use in the treatment of certain CNS disorders such as anxiety, depression, epilepsy, obsessive compulsive disorder, attention deficit disorder, migraine, cognitive memory enhancement (e.g. for the treatment of Alzheimer""s disease), sleep disorders, feeding disorders (e.g. anorexia or bulimia), neurodegenerative disorders (e.g. stroke or head trauma), panic attacks, withdrawal from drug abuse (e.g. cocaine, ethanol, nicotine or benzodiazepines), schizophrenia, or the like; or in the treatment of certain gastrointestinal disorders such as irritable bowel syndrome.
Therefore, it is an object of this invention to provide compounds which are useful as therapeutic agents in the treatment of a variety of central nervous system disorders related to or affected by the 5-HT6 receptor.
It is another object of this invention to provide therapeutic methods and pharmaceutical compositions useful for the treatment of central nervous system disorders related to or affected by the 5-HT6 receptor.
It is a feature of this invention that the compounds provided may also be used to further study and elucidate the 5-HT6 receptor.
These and other objects and features of the invention will become more apparent by the detailed description set forth hereinbelow.
The present invention provides an indolylalkylamine derivative of formula I 
wherein
W is SO2, CO, CONR11 or CSNR12;
X is N or CR1;
Y is N or CR2;
Z is N or CR3;
Q is N or CR4 with the proviso that no more than two of X, Y, Z and Q may be N;
n is an integer of 2 or 3;
R1, R2, R3 and R4 are each independently H, halogen, CN, OCO2R13, CO2R14, CONR15R16, CNR17NR18R19, SOmR20, NR21R22, OR23, COR24 or a C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C6cycloalkyl, cycloheteroalkyl, aryl or heteroaryl group each optionally substituted;
R5 and R6 are each independently H or a C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C6cycloalkyl, cycloheteroalkyl, aryl or heteroaryl group each optionally substituted, or R5 and R6 may be taken together with the atom to which they are attached to form an optionally substituted 5- to 7-membered ring optionally containing an additional heteroatom selected from O, N or S;
R7 and R8 are each independently H or an optionally substituted C1-C6alkyl group;
R9 is H, halogen, or a C1-C6alkyl, C1-C6alkoxy, aryl or heteroaryl group each optionally substituted;
R10 is an optionally substituted C1-C6alkyl, aryl, or heteroaryl group or an optionally substituted 8- to 13-membered bicyclic or tricyclic ring system having a N atom at the bridgehead and optionally containing 1, 2 or 3 additional heteroatoms selected from N, O or S with the proviso that when Q is N and X, Y and Z are CH then R10 must be other than phenyl;
m is 0 or an integer of 1 or 2;
R11 and R12 are each independently H or a C1-C6alkyl, aryl or heteroaryl group each optionally substituted;
R13, R14, R20, R23 and R24 are each independently H or a C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, C3-C6cycloalkyl, cycloheteroalkyl, aryl or heteroaryl group each optionally substituted;
R15 and R16 are each independently H or an optionally substituted C1-C6alkyl group; and
R17, R18, R19, R21 and R22 are each independently H or an optionally substituted C1-C4alkyl group; or R21 and R22 may be taken together with the atom to which they are attached to form a 5- to 7-membered ring optionally containing another heteroatom selected from O, N or S; or
the stereoisomers thereof or the pharmaceutically acceptable salts thereof.
The present invention also provides methods and compositions useful for the therapeutic treatment of central nervous system disorders related to or affected by the 5-HT6 receptor.