The present invention relates to compounds of general formula (I), ##STR1##

wherein R¹-R⁴ have the meanings given in the specification, A is CH2, CHOH or CH—(C₁-C₃-alkyl), B and C are independently CH₂ or CH—(C₁-C₃-alkyl), and R⁵ is an aryl or heteroaryl group optionally substituted by the substituents listed in the specification. The compounds are useful for the manufacture of medicaments for the treatment of cardiovascular diseases, stable or unstable angina pectoris, coronary heart disease, Prinzmetal angina, acute coronary syndrome, heart failure, myocardial infarction, stroke, thrombosis, peripheral artery occlusive disease, endothelial dysfunction, atherosclerosis, restenosis, endothelial damage after PTCA, hypertension, essential hypertension, pulmonary hypertension, secondary hypertension, renovascular hypertension, chronic glomerulonephritis, erectile dysfunction, ventricular arrhythmia, diabetes or diabetes complications, nephropathy or retinopathy, angiogenesis, asthma bronchiale, chronic renal failure, cirrhosis of the liver, osteoporosis, and restricted memory performance or a restricted ability to learn, or the lowering of cardiovascular risk of postmenopausal women or after intake of contraceptives.