Patent ID: 7960545

Claim:
A process for preparing Erlotinib [N-(3-ethynylphenyl)-6,7-bis(2-methoxy-ethoxy)-4-quinazolinamine] of formula (1), or a pharmaceutically acceptable salt thereof; the process comprising: (i) reacting 6,7-dimethoxy-4(3H)-quinazolinone of formula (8) with aqueous hydrobromic acid or pyridine hydrochloride to get a hydrobromide or hydrochloride salt and neutralizing with a base to get a compound of formula (9) (ii) acylating the compound of formula (9) using acylating agent at a temperature of 20-150° C. and in the presence of a catalyst to get a bis-acylated derivative of formula (10); (iii) converting the compound of formula (10) into a leaving group ‘X’ by using an appropriate reagent in the presence or absence of a solvent at 10-100° C. to get a compound of formula (11) in which X is Halogen, OMs, OTs, or OBs; (iv) condensing the reaction mixture containing the compound of formula (11) with 3-ethynylaniline in an organic solvent at 10-100° C. to get a compound of formula (12), wherein X is halogen, OMs, OTs, or OBs; (v) reacting the compound of formula (12) with a base at 20 to 60° C. to get a deacylated compound of formula (13), (vi) reacting the compound of formula (13) with a 2-halo-ethylmethyl ether in the presence of a base at 25-100° C. to get erlotinib base of the formula (1), (vii) recrystallising the erlotinib base from (vi) to get purified erlotinib base.