Compound of the formula in which L represents straight-chain (C 1 -C 12) alkanediyl which may be substituted up to four times with methyl and in which ( a) two carbon atoms in 1,2 relation, 1,3 relation or 1,4 relation to one another including the carbon atoms optionally lying between them may be bridged to form a (C 3 -C 6) cycloalkyl ring or a phenyl ring or ( b) up to three CH 2 groups not adjacent to one another may be exchanged for -O-, R 1 represents hydrogen or methyl, R 2 represents isopropyl, isobutyl, sec.-butyl, tert. -butyl, 1-hydroxyethyl, phenyl, benzyl, 4-hydroxybenzyl, 1-phenylethyl, diphenylmethyl, 1 H -imidazol-4-ylmethyl or 1 H -indol-3-ylmethyl, or R 1 and R 2 together with the carbon atom to which they are both bound, form a 2-phenylcyclopropan-1,1-diyl group of the formula wherein # indicates the points of attachment with the remaining parts of the molecule, and T represents a group of the formula -C(=O)-OR 3, -C(=O)-NR 4 R 5, -C(=O)-NH-NH-R 6 or -CH 2 -O-R 7, wherein R 3 denotes hydrogen, (C 1 -C 6) alkyl or (C 3 -C 10) cycloalkyl, wherein (C 1 -C 6) alkyl may be substituted with phenyl, naphthyl or (C 3 -C 10) cycloalkyl, R 4 denotes hydrogen or (C 1 -C 6) alkyl, R 5 denotes hydrogen, (C 1 -C 6) alkyl or (C 3 -C 10) cycloalkyl, wherein (C 1 -C 6) alkyl may be substituted with phenyl, or R 4 and R 5 are linked to one another and together with the nitrogen atom to which they are bound, form a 5-membered to 7-membered, saturated aza-heterocycle, which may contain a further ring heteroatom from the series >N-H, >N-CH 3 or -O- which is located in 1,3-position or optionally 1,4-position in relation to the first-mentioned nitrogen atom, R 6 denotes (C 1 -C 6) alkyl, (C 1 -C 6) alkylcarbonyl, phenyl or benzoyl, and R 7 denotes (C 1 -C 6) alkyl which may be substituted with phenyl, wherein phenyl in turn may be substituted with (C 1 -C 6) alkoxycarbonyl or carboxyl, as well as its salts, solvates and solvates of the salts. L represents straight-chain (C 1 -C 12) alkanediyl which may be substituted up to four times with methyl and in which ( a) two carbon atoms in 1,2 relation, 1,3 relation or 1,4 relation to one another including the carbon atoms optionally lying between them may be bridged to form a (C 3 -C 6) cycloalkyl ring or a phenyl ring or ( b) up to three CH 2 groups not adjacent to one another may be exchanged for -O-, R 1 represents hydrogen or methyl, R 2 represents isopropyl, isobutyl, sec.-butyl, tert. -butyl, 1-hydroxyethyl, phenyl, benzyl, 4-hydroxybenzyl, 1-phenylethyl, diphenylmethyl, 1 H -imidazol-4-ylmethyl or 1 H -indol-3-ylmethyl, R 1 and R 2 together with the carbon atom to which they are both bound, form a 2-phenylcyclopropan-1,1-diyl group of the formula wherein # indicates the points of attachment with the remaining parts of the molecule, and # indicates the points of attachment with the remaining parts of the molecule, T represents a group of the formula -C(=O)-OR 3, -C(=O)-NR 4 R 5, -C(=O)-NH-NH-R 6 or -CH 2 -O-R 7, wherein R 3 denotes hydrogen, (C 1 -C 6) alkyl or (C 3 -C 10) cycloalkyl, wherein (C 1 -C 6) alkyl may be substituted with phenyl, naphthyl or (C 3 -C 10) cycloalkyl, R 4 denotes hydrogen or (C 1 -C 6) alkyl, R 5 denotes hydrogen, (C 1 -C 6) alkyl or (C 3 -C 10) cycloalkyl, wherein (C 1 -C 6) alkyl may be substituted with phenyl, or R 4 and R 5 are linked to one another and together with the nitrogen atom to which they are bound, form a 5-membered to 7-membered, saturated aza-heterocycle, which may contain a further ring heteroatom from the series >N-H, >N-CH 3 or -O- which is located in 1,3-position or optionally 1,4-position in relation to the first-mentioned nitrogen atom, R 6 denotes (C 1 -C 6) alkyl, (C 1 -C 6) alkylcarbonyl, phenyl or benzoyl, and R 7 denotes (C 1 -C 6) alkyl which may be substituted with phenyl, wherein phenyl in turn may be substituted with (C 1 -C 6) alkoxycarbonyl or carboxyl,