Abstract: The present invention relates to novel heterocyclic compounds useful in preparing drugs for the treatment of diseases associated with various functions of the histamine 4 receptor. Specifically, these drugs are useful in the prevention or treatment of inflammatory disorder, allergy, pain, nasal polyps, rhinitis, chronic sinusitis, nasal congestion, nasal itch, asthma, chronic obstructive pulmonary disease, rheumatoid arthritis, atopic dermatitis, psoriasis, eczema, pruritus, itch skin, urticaria, idiopathic chronic urticaria, scleroderma, conjunctivitis, keratoconjunctivitis, ocular inflammation, dry eye, age-related macular degeneration, cardiac dysfunction, arrhythmia, atherosclerosis, multiple sclerosis, inflammatory bowel disease (colitis, Crohn's disease, ulcerative colitis), inflammatory pain, neuropathic pain, osteoarthritic pain, autoimmune thyroid disease, immune-mediated (also known as type I) diabetes, lupus, post-operative adhesions, vestibular disorders and cancer.

Abstract: A heterocyclic derivative represented by formula (I), or a pharmaceutically acceptable salt or a stereoisomer thereof, which has an inhibitory effect on the activation of STAT3 protein, and is useful for the prevention or treatment of diseases associated with the activation of STAT3 protein.

Abstract: A heterocyclic derivative represented by formula (I), or a pharmaceutically acceptable salt or a stereoisomer thereof, which has an inhibitory effect on the activation of STAT3 protein, and is useful for the prevention or treatment of diseases associated with the activation of STAT3 protein.