Piperidinylamino-thieno[2,3-D] pyrimidine compounds

Disclosed are piperidinyl substituted thieno[2,3-d]pyrimidine compounds of formula (II), (IV) and (VI), The substituents are as disclosed in the description. The compounds are suitable for use as 5-HT 2B receptor antagonists. Also disclosed is the pharmaceutical composition of compounds of formula (II), (IV) and (VI) and the use as a medicament to treat pulmonary hypertension, erectile dysfunction, systemic hypertension, congestive heart failure (CHF), migraine, hypertension, a disorder of the gastrointestinal tract, restenosis, asthma, obstructive airway disease, prostatic hyperplasia, priapism, inflammatory pain, neuropathic pain, cancer pain, acute pain, chronic pain, irritable bowel syndrome, hypertonic lower esophageal sphincter, a motility disorder, benign prostatic hypelplasia, depression, anxiety, attention deficit hyperactivity disorder, obesity, sleeping disorder, Alzheimer's disease, Parkinson's disease, a carcinoid tumour, teratocarcinoma, hyperprolactinemia, acromegaly and central nervous system (CNS) disorder.