Industrial synthesis of serinol

A process for preparing Iopamidol of formula (III):

• comprising the following steps:
• i) reacting glycerol or glycerol 1,2-carbonate with urea at a temperature higher than or equal to 130° C. in the presence of a catalyst selected from Mg, MgO, Mg(OMe)2, Mg(OH)2 and La2O3 thus obtaining the compound of formula (II)
• ii) hydrolyzing the compound of formula (II) to obtain 2-amino-1,3-propanediol (serinol) of formula (I):
• iv) reacting the compound of formula (I) thus obtained with the compound of formula (IV)
• v) hydrolyzing the resultant compound of formula (IV)
• by removing the acetyl protecting group.

A process for preparing Iopamidol of formula (III):

• comprising the following steps:
• i) reacting glycerol or glycerol 1,2-carbonate with urea at a temperature higher than or equal to 130° C. in the presence of a catalyst selected from Mg, MgO, Mg(OMe)2, Mg(OH)2 and La2O3 thus obtaining the compound of formula (II)
• ii) hydrolyzing the compound of formula (II) to obtain 2-amino-1,3-propanediol (serinol) of formula (I):
• vi) reacting the compound of formula (I) thus obtained with the compound of formula (VII)
• wherein R is a straight or branched C1-C4 alkyl group, to provide the 5-amino-N,N′-bis[2-hydroxy-1-(hydroxymethyl)ethyl]-1,3-benzenedicarboxamide (VI)
• vii) iodinating the compound (VI) at positions 2,4,6 to provide the 5-amino-N,N′-bis[2-hydroxy-1-(hydroxymethyl)ethyl]-2,4,6-triiodo-1,3-benzenedicarboxamide (VIII)
• viii) treating compound (VIII) with a boronic acid, a borate ester or a boroxine to provide the corresponding compound (IX)
• wherein X is —OR2 or —R3 and wherein R2 and R3 are a C1-C6 linear or branched alkyl, C3-C6 cycloalkyl, C6 aryl, optionally substituted with a group selected from methyl, ethyl, n-propyl, i-propyl, n-butyl, sec-butyl, t-butyl and phenyl;
• ix) reacting the compound (IX) with the acylating agent (S)-2-(acetyloxy)propanoyl chloride and hydrolyzing the resultant intermediate to obtain Iopamidol (III).