Method for synthesizing d3 dopamine receptor agonists

A method for producing a compound according to formula (I):

• wherein:
• R1, R2 and R3 are independently selected from the group consisting of H, cyano, hydroxyl, amino, acetamido, halo, alkoxy, nitro, C1-6alkyl, substituted C1-6alkyl, heteroalkyl, heterocyclyl, substituted heterocyclyl, aryl, substituted aryl, aryl-(C1-3)alkyl, substituted aryl-(C1-3)alkyl, carboxy, alkylcarboxy, formyl, alkyl-carbonyl, aryl-carbonyl, and heteroaryl-carbonyl;
• R4 and R5 are independently selected from the group consisting of H, C1-6 alkyl, substituted C1-6 alkyl, heteroalkyl, heterocyclyl, substituted heterocyclyl, aryl, substituted aryl, aryl-(C1-3)alkyl, and substituted aryl-(C1-3)alkyl;
• n is an integer from 2 to 8;
• each X is independently O, C(R6)2, N, or S, where R6 is H, cyano, hydroxyl, amino, acetamido, halo, alkoxy, nitro, C1-6 alkyl, substituted C1-6 alkyl, heteroalkyl, heterocyclyl, substituted heterocyclyl, aryl, substituted aryl, aryl-(C1-3)alkyl, substituted aryl-(C1-3)alkyl, carboxy, alkylcarboxy, formyl, alkyl-carbonyl, aryl-carbonyl, and heteroaryl-carbonyl;
• and
• each Y is independently O, C(R7), N or S, with at least three 2 Y being C(R7), where R7 is H, cyano, hydroxyl, amino, acetamido, halo, alkoxy, nitro, C1-6 alkyl, substituted C1-6 alkyl, heteroalkyl, heterocyclyl, substituted heterocyclyl, aryl, substituted aryl, aryl-(C1-3)alkyl, substituted aryl-(C1-3)alkyl, carboxy, alkylcarboxy, formyl, alkyl-carbonyl, aryl-carbonyl, and heteroaryl-carbonyl;
• said method comprising:
• a) reacting a compound of formula (II)
• where R1, R2, R3, R5, n, X, and Y are as defined above;
• with a sulfinamide according to formula (III)
• where R8 is optionally substituted C1-C6 alkyl or heteroalkyl or optionally substituted C6-C24 aryl or heteroaryl to form a compound of formula (IV)
• where R1-R3, R5, R8, X, Y, and n are as defined above;
• b) reducing the compound of formula (IV) to form a compound of formula (V)
• where R1-R3, R5, R8, X, Y, and n are as defined above;
• and
• c) hydrolyzing the compound of formula (V) and optionally alkylating or arylating to form the compound according to formula (I).