Process for the preparation of carbamoylamino pyrazole derivatives

Process for production of a compound of formula

• wherein
• R1 is H, straight or branched C1-C6 alkyl, optionally substituted by 1 to 5 hydroxy groups which may be protected or halogen atoms,
• R2 is H, straight or branched C1-C6 alkyl or an amino protecting group, or R1 and R2 are bonded together to form C1-C6 alkylene or C2-C6 alkenylene,
• R3 is H, straight or branched C1-C6 alkyl or an amino protecting group, wherein R3 is not H if R2 is H,
• R4 is
• wherein
• a is 0, 1, 2, 3, 4, 5 or 6,
• R5 is H or hydroxy which may be protected, and
• R6 is H, C1-C6 straight or branched alkyl, mono or di straight or branched C1-C6 alkylamino, C3-C6 cycloalkyl, C3-C6 cycloalkyl amino, C6-C12 aryl, C6-C12 aryl amino, protected amino, protected guanidino or a saturated 3- to 8-membered heterocyclic group containing 1 to 4 nitrogen atoms, wherein the cycloalkyl or aryl is optionally substituted by one or more C1-C3 straight or branched alkyl and the heterocyclic group is optionally substituted by one or more protected amino groups
• comprising reacting a compound of formula
• wherein R1, R2 and R3 are as defined above
• with a compound of formula
• wherein a, R5 and R6 are as defined above
• and PhI(OAc)2 in the presence of a non-nucleophilic base to produce the compound of formula I.