Patent Number: 8,716,471

Title: Process for the preparation of tetrazine derivatives

Abstract: The present invention provides a process for the preparation of a tetrazine derivative of formula (I), or a pharmaceutically acceptable salt thereof wherein R.sub.1 represents a hydrogen atom, a straight or branched C.sub.1-C.sub.6 alkyl group, C.sub.2-C.sub.6 alkenyl group or C.sub.2-C.sub.6 alkynyl group, which C.sub.1-C.sub.6 alkyl group, C.sub.2-C.sub.6 alkenyl group and C.sub.2-C.sub.6 alkynyl group is unsubstituted or substituted with 1, 2 or 3 substituents selected from halogen atoms, straight or branched C.sub.1-C.sub.4 alkoxy groups, C.sub.1-C.sub.4 alkylthio groups, C.sub.1-C.sub.4 alkylsulphinyl groups, C.sub.1-C.sub.4 alkylsulphonyl groups and phenyl groups, which phenyl groups are unsubstituted or substituted with one or more substituents selected from C.sub.1-C.sub.4 alkyl groups, C.sub.1-C.sub.4 alkoxy groups and nitro groups; or R.sub.1 represents a C.sub.3-C.sub.8 cycloalkyl group; and R.sub.2 represents a group of formula --(C.dbd.O)NR.sub.3R.sub.4, wherein R.sub.3 and R.sub.4 are independently selected from hydrogen atoms, C.sub.1-C.sub.4 alkyl groups, C.sub.2-C.sub.4 alkenyl groups and C.sub.3-C.sub.8 cycloalkyl groups, which process comprises: i) providing a compound N of formula (III), wherein R.sub.1 is as defined; R.sub.1--N.dbd.C.dbd.O ii) absorbing the compound of formula (III) into a solvent to obtain a solution of the compound of formula (III); iii) adding to the thus obtained solution a compound of formula (II), to obtain a compound of formula (I), as defined above, wherein R.sub.2 is as defined above; iv) decomposing any excess compound of formula (III) remaining by addition of water; and v) optionally salifying the thus obtained compound with a pharmaceutically acceptable acid, or base. ##STR00001##

Inventors: Rajan; Gupte (Maharashtra, IN), Rohit; Chaturvedi (Maharashtra, IN), Pravin; Baviskar (Maharashtra, IN)

Assignee: Reliance Life Sciences Pvt. Ltd.

International Classification: C07D 487/04 (20060101); A61K 31/395 (20060101); A61P 35/00 (20060101)

Expiration Date: 5/06/12018