There is provided a compound of formula (III), and a process for preparing a compound of formula (V) comprising converting a compound of formula (III) to the compound (V), wherein (X) is fluoro, chloro, bromo or iodo. There is also provided a process for preparing a compound of formula (XI) comprising converting a compound of formula (X) to the compound (XI). The compounds (V) and (XI) so prepared may be used in a process for preparing gefitinib.
A process for producing a quinazolin-4-one compound having the formula:
[wherein R
1
, R
2
, R
3
and R
4
each represents a group not participating in the below-mentioned reaction, and R
1
, R
2
, R
3
and R
4
can be combined together to form a ring] which comprises reacting an anthranilic acid derivative having the formula:
[wherein R
5
is a hydrogen atom or a hydrocarbyl group] with a formic acid derivative in the presence of an ammonium carboxylate.