Patent ID: 7514580

Claim:
A process for the preparation of a compound of the formula and pharmaceutically acceptable addition salts thereof wherein R 1 , R 1′ are independent of each other H or C 1-20 alkyl, R 2 is a C 1-20 alkyl and R 3 , R 4 are independent of each other H or an C 1-6 alkanoyl, with the proviso that not both R 3 and R 4 are H, which process comprises a) esterifying 5-amino shikimic acid of formula with R 2 OH to form a compound of formula wherein R 2 is as defined above; b) reacting the compound of formula III with an alkanone to form a ketal of formula wherein R 1 , R 1′ and R 2 are as defined above, c) effecting reductive ketal opening to form a compound of formula wherein R 1 , R 1′ and R 2 are as defined above, d) transforming the aminoalcohol of formula V into a diamino compound of formula By d1) substituted or one or both hydrogens of the amino group of the compound of Formula V with an amino protecting group, d2) esterifying the hydroxyl group to form a reactive ester leaving group, and d3) reacting the product from steps d1) and d2) with an amine of the formula R 5 NHR 6 to form the compound of formula VI, wherein R 1 , R 1′ and R 2 are as defined above, R 5 and R 6 , independently of each other are H or an amino protecting group, with the proviso that R 5 and R 6 cannot both be H, e) acylating the free amino function of compound of formula VI to form an acylated compound of formula wherein R 1 , R 1′ , R 2 , R 3 , R 4 , R 5 and R 6 are as defined above, and f) reducing the compound of formula VII to compound of formula I and optionally further forming a pharmaceutically acceptable addition salt.