The present invention is concerned with deuterium-enriched pyrimidine compounds of formula 1, their derivatives and pharmaceutically acceptable salts and methods of use thereof for the prevention and treatment of neuroendocrine neoplasia including metastasis and fibrosis, fibrotic processes associated with neuroendocrine cell dysregulation for example Crohn's disease, pulmonary arterial hypertension, pulmonary hypertension associated with chronic obstructive pulmonary disease (COPD), right ventricular hypertrophy, pulmonary vascular remodeling, asthma, cystic fibrosis, hypertension, ischemic stroke, angina pectoris, congestive heart failure, arrhythmia, arterial fibrillation, neurodenerative diseases, gastrointestinal disorders , stress disorders, obsessive compulsive disorders, demyelinating diseases, cereberal vascular disorders, bronchoconstriction, vasodilation, smooth muscle contraction, brain disorders, vascular disorders, neuropathological diseases and cardiovascular system regulation.