Compounds of general formula I R1 is selected from any one of phenyl, pyridinyl, thienyl, furanyl, imidazolyl, pyrrolyl, triazolyl, thiazolyl, and pyridine N-oxide; R2 is independently selected from ethyl and isopropyl; R3 is independently selected from hydrogen and fluoro; R4 is independently selected from —OH, —NH2 and —NHSO2R5; and R5 is independently selected from hydrogen, —CF3 and C1–C6 alkyl, or salts thereof or separate enantiomers and salts thereof; where each R1 heteroaromatic ring may optionally and independently be further substituted by 1, 2 or 3 substituents selected from straight and branched C1–C6 alkyl, NO2, CF3, C1–C6 alkoxy, chloro, fluoro, bromo, and iodo. The substitutions on the heteroaromatic ring may take place in any position on said ring systems; are disclosed and claimed in the present application, as well as separate enantiomers of the compounds and salts and pharmaceutical compositions comprising the novel compounds and their use in therapy, in particular in the management of pain, anxiety and functional gastrointestinal disorders.