The present invention provides a compound of formula (1):wherein R1-L- is R1-OC (O)-, etc., R1is hydrogen atom, optionally-substituted C1-6alkyl group, optionally-substituted C3-8cycloalkyl group, etc., R2is hydrogen atom, etc., ring A is formula (2) or (3) wherein R3is hydrogen atom, optionally-substituted C1-6alkyl group, etc., (X, Y, Z) mean X=Y-Z, X-Y=Z or X-Y-Z, X is nitrogen atom, NR4(R4is hydrogen atom, optionally-substituted C1-6alkyl group, etc.), etc., Y is carbon atom, etc., Z is carbon atom, nitrogen atom, etc., as an agent useful for promoting nerve regeneration； and a pharmaceutical composition comprising the compound.本發明係一種式(1)所表示之化合物或其製藥學上容許之鹽。 [式中，R1-L-表示R1-OC(O)-等，R1表示氫原子、可經取代之碳數1～6之烷基、可經取代之3～8員之環烷基等，R2表示氫原子等，環A表示式(2)或式(3){式中，R3表示氫原子、可經取代之碳數1～6之烷基等，X、Y、Z所表示之部分表示X=Y-Z、X-Y=Z或X-Y-Z，X表示氮原子、NR4(R4係氫原子、可經取代之碳數1～6之烷基等)等，Y表示碳原子等，Z表示碳原子、氮原子等}]
