Patent ID: 6124472
Filing Date: 2000-09-26
Classification: C07D

Abstract:
A process for preparing 3-pyrroline-2-carboxylic acid derivatives of the formula I ##STR10## where R.sup.1 is H, C.sub.1 -C.sub.6 -alkyl, benzyl, benzyl substituted on the phenyl, allyloxycarbonyl, C.sub.1 -C.sub.6 -alkyloxycarbonyl, benzyloxycarbonyl where the benzyl residue can be substituted by OCH.sub.3 radicals, or C.sub.1 -C.sub.6 -alkylcarbonyl orR.sup.1 is a residue of an amino acid which is linked via the C terminus and may be alkylated or acylated on the nitrogen, andR.sup.2 is OH, C.sub.1 -C.sub.6 -alkyloxy, benzyloxy or N R.sup.3 4.sup.2,where R.sup.3 and R.sup.4 are independently of one another, H, C.sub.1 -C.sub.6 -alkyl, benzyl, phenyl or pyridyl,the aromatic systems in R.sup.3 and r.sup.4 being optionally substituted by up to three identical or different substituents selected from the group consisting of methyl, methoxy, hydroxyl, cyano or halogen,which comprises eliminating the sulfonic acid radical with the aid of a base selected from the group consisting of hydrides, amides and alcoholates of lithium, sodium, potassium, rubidium, cesium, calcium or magnesium from a compound of the formula II ##STR11## where R.sup.1 and R.sup.2 have the meanings described above, and R.sup.5 is C.sub.1 -C.sub.6 -alkyl, benzyl, trifluoromethyl, naphthyl or phenyl which may be unsubstituted or substituted by radicals from the group consisting of methyl, nitro or halogen.