A variety of pterin molecules were synthesized via an under-utilized acyl radical insertion, using aldehydes and α-keto esters as the acyl source. These reactions gave complete regiospecificity for the 7-isomer, with reaction times ranging in minutes, often with instantaneous product precipitation. This approach led to the construction of new pterin analogs unaccessible via traditional Friedel–Crafts acylation. The compounds were characterized by NMR spectroscopy and high-resolution mass spectroscopy.A variety of pterin molecules were synthesized via an under-utilized acyl radical insertion, using aldehydes and α-keto esters as the acyl source. These reactions gave complete regiospecificity for the 7-isomer, with reaction times ranging in minutes, often with instantaneous product precipitation. This approach led to the construction of new pterin analogs unaccessible via traditional Friedel–Crafts acylation. The compounds were characterized by NMR spectroscopy and high-resolution mass spectroscopy.