Compound: Esmirtazapine
SMILES: n1c2N3[C@@H](c4ccccc4Cc2ccc1)CN(C)CC3
InChIKey: RONZAEMNMFQXRA-MRXNPFEDSA-N
Synonyms: Esmirtazapine, (S)-Mirtazapine, 61337-87-9, (+)-Mirtazapine, (s)-6-azamianserin, Mirtazapine, (s)-, (s)-org 3770, esmirtazapina, Org-44-20, (S)-1,2,3,4,10,14b-Hexahydro-2-methylpyrazino(2,1-a)pyrido(2,3-c)(2)benzazepine, 4685R51V7M, DTXSID001029320, esmirtazapinum, RefChem:137870, DTXCID901514590, (7S)-5-methyl-2,5,19-triazatetracyclo(13.4.0.02,?.0?,13)nonadeca-1(15),8,10,12,16,18-hexaene, 262-714-0, S-Mirtazapine, Esmirtazapine [INN], (7S)-5-methyl-2,5,19-triazatetracyclo[13.4.0.02,7.08,13]nonadeca-1(15),8,10,12,16,18-hexaene, S-(+)-MIRTAZAPINE, (S)-Mirtazapine-13C-d3, Org 44-20, UNII-4685R51V7M, EINECS 262-714-0, (N-methyl-11C)mirtazapine, BIDD:PXR0200, SCHEMBL49330, ESMIRTAZAPINE [WHO-DD], orb1708745, CHEMBL1366933, SCHEMBL29579803, HY-B0352A, RONZAEMNMFQXRA-MRXNPFEDSA-N, GLXC-15311, ARD193994, PDSP1_001530, PDSP2_001514, AKOS040736264, DB06678, DA-48862, MS-23753, CS-0086936, NS00087199, G17036, Q3058085, (S)-2-methyl-1,2,3,4,10,14b-hexahydrobenzo[c]pyrazino[1,2-a]pyrido[3,2-f]azepine, (14BS)-1,2,3,4,10,14B-HEXAHYDRO-2-METHYLPYRAZINO(2,1-A)PYRIDO(2,3-C)(2)BENZAZEPINE, (7S)-5-methyl-2,5,19-triazatetracyclo[13.4.0.0?,?.0?,??]nonadeca-1(15),8,10,12,16,18-hexaene, PYRAZINO(2,1-A)PYRIDO(2,3-C)(2)BENZAZEPINE, 1,2,3,4,10,14B-HEXAHYDRO-2-METHYL-, (14BS)-
Theoretical properties:
molecular_formula: C17H19N3
molecular_weight: 265.35 g/mol
exact_mass: 265.157897619 g/mol
formal_charge: 0
hydrogen_bond_donor_count: 0
hydrogen_bond_acceptor_count: 3
rotatable_bond_count: 0
heavy_atom_count: 20
topological_polar_surface_area: 19.4 Å²
isotope_atom_count: 0
covalently_bonded_unit_count: 1
Physical properties:
solubility: Soluble in methanol and chloroform mg/mL (20 °C)
Descriptions:
chembl: ESMIRTAZAPINE is a small molecule listed in the ChEMBL database and has reached clinical trial phase 3.0.
wikipedia: Esmirtazapine (ORG-50,081) is a tetracyclic antidepressant drug that was under development by Organon for the treatment of insomnia and vasomotor symptoms (e.g., hot flashes) associated with menopause. Esmirtazapine is the (S)-(+)-enantiomer of mirtazapine and possesses similar overall pharmacology, including inverse agonist actions at H1 and 5-HT2 receptors and antagonist actions at α2-adrenergic receptors.   
Notably, esmirtazapine has a shorter half life of around 10 hours, compared to R-mirtazapine and racemic mixture, which has a half-life of 18–40 hours. Merck has run several studies on low dose (3–4.5 mg) esmirtazapine for the treatment of insomnia. It is attractive for treating insomnia since it is a potent H1-inhibitor and a 5-HT2A antagonist. Unlike low-dose mirtazapine, the half life (10 hours) is short enough that next-day sedation may be manageable, however, for people with CYP2D6 polymorphisms, which constitute a sizable fraction of the population, the half-life is expected to be quite a bit longer. Merck researchers claimed that the incidence of next-day sedation was not a problem in one of their studies, but this claim has been challenged (15% of patients complained of daytime sleepiness vs 3.5% in the placebo group).
In March 2010, Merck terminated its internal clinical development program for esmirtazapine for hot flashes and insomnia, "for strategic reasons".