Chemical process

A process for the preparation of a compound of formula I or a pharmaceutically acceptable salt thereof ##STR3## wherein Q is selected from the group consisting of furyl, thienyl, oxazolyl, thiazolyl, isoxazolyl and isothiazolyl, optionally bearing 1 or 2 substituents independently selected from (1-4C)alkyl and halogeno;

• R.sup.1 is hydrogen, (1-6C)alkyl, or (1-4C)alkanoyl;
• R.sup.2 is hydrogen, (3-12C)cycloalkyl, (3-6C)alkenyl, phenyl(3-6C)alkenyl, tetrafluorophenyl, pentafluorophenyl, pyridyl, isoxazolyl, thiadiazolyl, optionally substituted (1-6C)alkyl or optionally substituted phenyl,
• wherein said optionally substituted alkyl is unsubstituted or substituted with one or (3-6C)cycloalkyl, optionally substituted 5- or 6-membered heteroaryl wherein said heteroaryl is selected from furyl, pyridyl and thienyl, optionally substituted phenyl and a group of formula R.sup.10 (CO).sub.n Xb(CO).sub.m ;
• wherein R.sup.10 is (1-6C)alkyl, (3-6C)cycloalkyl, optionally substituted phenyl or optionally substituted phenyl(1-4C)alkyl;
• wherein n+m is 0 or 1, provided that when m is O, X and Xb are separated by at least two carbon atoms;
• wherein Xb is oxy, thio, sulphinyl, sulphonyl or an imino group of formula --NRb in which Rb is hydrogen, (1-6C)alkyl or together with R.sup.10 and the adjacent nitrogen atom forms a 4 to 6-membered saturated heterocyclic ring;
• wherein said optionally substituted 5- or 6-membered heteroaryl selected from furyl, pyridyl and thienyl is unsubstituted or substituted with 1 or 2 of (1-4C)alkyl, (1-4C)alkoxy and halogeno;
• and
• wherein any of said optionally substituted phenyl is unsubstituted or substituted by (1-4C)alkylenedioxy or by 1, 2 or 3 of halogeno, cyano, trifluoromethyl, (1-4C)alkoxycarbonyl, hydroxy, (1-4C)alkanoyloxy, benzyloxy, halogenobenzyloxy, nitro, and (1-4C)alkyl or alkoxy optionally bearing a group of formula R.sup.11 CO;
• wherein R.sup.11 is (1-4C)alkoxy, (3-6C)alkylamino, (3-6C)cycloalkylamino or [N-(1-4C)alkyl][N-(1-4C)dialkylamino(1-4C)alkyl]amino, and sulphamoyl of formula --SO.sub.2.NR.sup.3 R.sup.4
• wherein R.sup.3 and R.sup.4 are independently hydrogen or (1-4C)alkyl, or R.sup.3 is hydrogen and R.sup.4 is [(2-5C)alkoxycarbonyl]methyl, carbamoylmethyl or [N-(1-4C)alkylcarbamoyl]methyl;
• and
• wherein X is oxy, thio, sulphinyl, sulphonyl or an imino group of formula --NRa-- is which Ra is hydrogen, (1-6C)alkyl or together with R.sub.2 and the adjacent nitrogen atom forms a 4 to 6-membered saturated heterocyclic ring;
• and
• wherein A is N;
• which process comprises the steps of
• (a) reacting a N-2-(4,6-diaryloxy)-[1,3,5]triazinyl-N'-(heteroarylcarbonyl)hydrazine with a polyphosphoric acid silyl ester to afford a compound of formula II ##STR4## in which Za and Zb ar aryloxy groups;
• (b) reacting the compound of formula II with a compound of formula R.sup.1 NH.sub.2 to afford a compound of formula VI, ##STR5## where Zb is an aryloxy group;
• and (c) reacting the compound of formula VI with a compound of formula R.sup.2 XH to form a compound of formula I.