Compounds having antitumor activity: process for their preparation and pharmaceutical compositions containing them

A compound of formula (1) and its stereoisomers, polymorphs and pharmaceutically acceptable salts are described wherein: R1, R2 and R3 are the same or different and independently represent hydrogen or substituted or unsubstituted groups selected from linear or branched (C1-C8) alkyl group, phenyl, heteroaryl group selected from pyridyl, furyl or thiophenyl; aralkyl selected from benzyl or phenethyl; heteroaralkyl group selected from pyridylmethyl, pyridylethyl, furanmethyl or furanethyl; (C2-C8) alkanoyl, (C3-C8) alkenoyl, benzoyl, heteroaroyl group selected from pyridyl carbonyl or furyl carbonyl; sulfonyl group selected from methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl; or a group -(CO)-W-R4 where W represents O, S or NR5, wherein R5 represents hydrogen or( C1-C6)alkyl group, R4 represents substituted or unsubstituted groups selected from (C1-C8)alkyl, phenyl, benzoyl, or aralkyl selected from benzyl or phenethyl, when the group represented by R4 is substituted the substituent is selected from halogen atom, amino, cyano, hydroxy, nitro, trifluorethyl, (C1-C8)alkyl or (C1-C6) alkoxy; Or R2 and R3 together form a substituted or unsubstituted 5 to 7 membered cyclic structure containing carbon and oxygen atoms; wherein the substituents on R1, R2 and R3 are selected from cyano, hydroxy, nitro, halogen atom, amino, alkanoyl, aroyl, acyloxy (C1-C6) alkoxy, substituted or unsubstituted (C1-C8) alkyl, wherein when the alkyl group is substituted the substituent is selected from halogen, hydroxy, nitro, cyano, amino, phenyl or (C1-C6) alkoxy; substituted of unsubstituted aryl group selected from phenyl or napthyl wherein when the aryl group is substituted the substituent is selected from (C1-C6) alkyl, halogen atom, amino, cyano, hydroxy, nitro, trifluoroethyl or (C1-C6) alkoxy; and wherein the aryl group is disubstituted, the two substituents on the adjacent carbon atoms form a linking group selected from -X-CH2-Y-, -X-CH2-CH2-Y-, where X and Y may be same or different and independently represent O, N, S or CH2; thio, thioalkyl, alkylthio, heteroaryl selected from pyridyl, furyl or thienyl; mono(C1-C6) alkylamino, di(C1-C6)alkylamino, acylamino, arylamino, aralkylamino,alkoxycarbonylamino, aryloxycarbonylamino, aralkoxycarbonylamino, or COOR, where R represents hydrogen or(C1-C6)alkyl groups; wherein when the groups represented by R1, R2 or R3 are multisubstituted, the substituents present on the two adjacent carbons may form a linking group -X-(CR6R7)n-Y