[3-AMINO]-TETRAHYDROCARBAZOLE-PROPANOIC ACID ESTERS

The invention relates to new [3-amino]- tetrahydrocarbazole-propanoic acid esters which can be used as intermediates for the preparation of known thromboxane- antagonistic active compounds, and to a method for the purification of these active compounds. The new compounds have the general formula (I): (see formula I) wherein R represents C1-10-alkyl, or a salt thereof. Also provided are processes for preparing the compound (I), comprising: a) reacting a tetrahydrocarbazole of the formula (II) (see formula II) in which R1 represents hydrogen or methyl, and Aryl represents naphthyl or phenyl, with an acrylic ester of the formula (III) H2C=CH-COOR (III) and subsequently removing the group -CH(R1)-Aryl; or b) reacting a tetrahydrocarbazole of the formula (IV) (see formula IV) with an acrylic ester of formula (III) as defined above.