1,1-Dimethylethyl N-((3R)-1-(7-(2-butyn-1-yl)-2,3,6,7-tetrahydro-3-methyl-1-((4-methyl-2-quinazolinyl)methyl)-2,6-dioxo-1H-purin-8-yl)-3-piperidinyl)carbamate

It undergoes deprotection (removal of the tert-butyloxycarbonyl group) to yield the final active pharmaceutical ingredient. 1,1-Dimethylethyl N-((3R)-1-(7-(2-butyn-1-yl)-2,3,6,7-tetrahydro-3-methyl-1-((4-methyl-2-quinazolinyl)methyl)-2,6-dioxo-1H-purin-8-yl)-3-piperidinyl)carbamate, often known as N-Boc Linagliptin, is the penultimate intermediate in the synthesis of the antidiabetic drug linagliptin.