H-Gln(Trt)-Gly-OH is a dipeptide used in peptide synthesis. The H indicates a free N-terminus, meaning there is no protective group on the amino group of the first amino acid, Gln (Glutamine). The side chain of glutamine is protected by a Trt (Trityl) group, which prevents the side chain amide from participating in unwanted reactions during synthesis. Gly (Glycine) is the second amino acid in the sequence, known for its small and flexible nature. The -OH at the C-terminus indicates a free carboxyl group, allowing the dipeptide to be further extended in peptide synthesis. This compound is used to incorporate glutamine and glycine into peptides, with specific protections in place to ensure selective reactions.