Process for the preparation of 3-substituted 5-amino-6H-thiazolo[4,5-d]pyrimidine-2,7-dione compounds

A process for the preparation of a compound of formula (I),

• wherein:
• R1 is H or C1-6alkyl;
• and
• R2 is H or hydroxy;
• or a pharmaceutically acceptable salt, or an enantiomer or diastereomer thereof;
• the process comprising one or more of the following steps:
• a) forming a compound (III) from a compound of formula (II);
• b) forming a compound (IV) from compound (III);
• c) forming a compound (V) from compound (IV);
• d) forming a compound (VI) from compound (V);
• e) forming a compound (VII) from compound (VI);
• f) forming a compound (VIII) from compound (VII);
• g) forming a compound (IX) from compound (VIII);
• h) forming a compound of formula (X) from compound (IX);
• wherein R1 is H or C1-6alkyl;
• i) forming a compound of formula (XII) by reacting compound (X) with a compound of formula (XI);
• wherein R2 is H or hydroxy;
• j) forming a compound of formula (I) via the hydrolysis of the compound of formula (XII),
• k) forming a compound of formula (XV) from the compound of formula (I);
• wherein Acid is selected from D-glutamic acid, L-mandelic acid, 1-hydroxy-2-naphthoic acid, citric acid, 4-aminosalicylic acid, L-tartaric acid, hippuric acid, malonic acid, glutaric acid, oxalic acid, fumaric acid, succinic acid, 4-amino-benzoic acid, 2,5-dihydroxybenzoic acid, L-malic acid, salicylic acid, maleic acid, (1S,3R)-(−)-camphoric acid, pamoic acid, mucic acid, palmitic acid, oleic acid, and lactobionic acid;
• and step l) forming a compound of formula (I) via dissociation from the compound of formula (XV).