Patent ID: 7851620

Claim:
A method for the preparation of a compound of formula (I): or a salt thereof; wherein R 1 is H, or C1-C8 alkyl, C2-C8 alkenyl, C2-C8 alkynyl, C5-C6 aryl, C6-C12 arylalkyl, or a heteroform of one of these, each of which may be optionally substituted; R 2 is H, or C1-C8 alkyl, C1-C8 heteroalkyl, C6-C14 arylalkyl, C6-C14 heteroarylalkyl, optionally fluorinated C1-C6 acyl, C6-C12 aroyl, arylsulfonyl, trialkylsilyl, or alkoxycarbonyl, each of which may be optionally substituted; or R 1 and R 2 may be taken together with the atoms to which they are attached to form a 5- or 6-member ring containing one nitrogen atom; R 3 is H, or —NR 4 R 5 ; R 4 is H, or C1-C4 alkyl; R 5 is H, or C1-C8 alkyl, C1-C8 heteroalkyl, C6-C14 arylalkyl, C6-C14 heteroarylalkyl, arylsulfonyl, trialkylsilyl, or alkoxycarbonyl, each of which may be optionally substituted; or —C(═X)R′ where X is O, S, or NH, and R′ is optionally fluorinated C1-C8 alkyl, C2-C8 alkenyl, C5-C12 aryl, or C6-C14 arylalkyl, each of which may be optionally substituted; or R 4 and R 5 may be taken together with nitrogen to form an imine, or an optionally substituted 3-8 membered monocyclic azacyclic ring or 8-12 membered bicyclic fused azacyclic ring, each of which may contain 0-2 additional heteroatoms selected from N, O, and S as ring members; R 6 is H, or C1-C8 alkyl, C1-C8 heteroalkyl, C6-C14 arylalkyl, C6-C14 heteroarylalkyl, optionally fluorinated C1-C6 acyl, C6-C12 aroyl, arylsulfonyl, trialkylsilyl, or alkoxycarbonyl, each of which may be optionally substituted; R 7 is H, or halo, —CN, optionally substituted C1-C6 acyl, —COOR 8 , or —C(O)NR 9 2 ; R 8 is H, or C1-C8 alkyl, C2-C8 alkenyl, C5-C6 aryl, C6-C14 arylalkyl, or trialkylsilyl; and each R 9 is independently H, or C1-C8 alkyl, C2-C8 alkenyl, C5-C6 aryl, C6-C14 arylalkyl, C6-C14 heteroarylalkyl, —OH, or C1-C4 alkoxy, each of which may be optionally substituted; or two R 9 on the same N can optionally cyclize to form a ring; and each of Y and Y′ is independently H, or halo, —OH, or —OR 10 , where R 10 is optionally fluorinated C1-C4 alkyl, C2-C4 alkenyl, C6-C14 arylalkyl, optionally fluorinated alkylsulfonyl, arylsulfonyl, optionally fluorinated C1-C6 acyl, or C6-C10 aroyl, each of which may be optionally substituted; said method comprising electrochemical oxidation of a compound of formula (II): in which the radicals R 1 , R 2 , R 3 , R 6 , R 7 , Y, and Y′ are as defined for formula (I).