New 8-substituted-xanthine derivatives, useful e.g. for treating diabetes and arthritis, act by inhibiting dipeptidylpeptidase-IV

摘要

8-substituted-xanthine derivatives (I), their tautomers, enantiomers, diastereomers or mixtures, and salts. 8-substituted xanthine derivatives of formula (I), their tautomers, enantiomers, diastereomers or mixtures, and salts, are new: R1 = hydrogen; 1-8C alkyl; 3-8C alkenyl or alkynyl; 3-4C alkenyl substituted by 1-2C alkoxycarbonyl, aminocarbonyl (optionally substituted by 1 or 2 1-3C alkyl) or het-CO; 1-6C alkyl substituted by Ra; phenyl(1-6C)alkyl, optionally ring-substituted by R10-R14; phenyl(1-4C)alkyl, optionally substituted in alkyl by Rz and in the ring by R10-R14; R10-R14-substituted phenyl; phenyl(2-3C) alkenyl, phenyl (or naphthyl)-(CH2)m-(A or B)-(CH2)n, naphthyl(1-3C)alkyl or phenylcarbonylmethyl (all optionally ring-substituted by R10-R14); (1,4-napththoquinon-2-yl; chromen-4-on-3-yl; 1-oxo- or 1,3-dioxo-indan-2-yl; 2,3-dihydro-3-oxo-benzofuran-2-yl; heteroaryl-(CH2)m-(A or B)-(CH2)n; 1-6C alkyl-A-(CH2)n; 3-7C cycloalkyl-(CH2)m-A or B)-(CH2)n; R21-A-(CH2)n; phenyl- or naphthyl-(CH2)m-D-(1-3C)alkyl; Rb-substituted 2-6C alkyl, or 3-6C cycloalkyl; amino, or arylcarbonylamino; het = pyrrolidin-1-yl, piperidin-1-yl or morpholin-4-yl; R10-R14, Rb and Rz = various substituents; m = 0-2; n = 1-3; A, B and D = various linking groups; R2 = hydrogen or a wide range of substituents; R3 = various substituents; R4 = a wide range of substituents. The full definitions are given in the DEFINITIONS (Full Definitions) Field.