Synthesis of novel 5-[2- aminoquinazolin-4-one-3-yl]-2- phthalimidomethylthiadiazole   2 from  5-[2-ethoxyquinazolin-4-one-3-yl]-2-phthalamidomethylthiadiazole. The behavior of as a nitrogen nucleophile towards an ±-hydroxy-aldehyde,  such as glucose and formation of Amadori rearrangement product (ARP) that has had occurred during the course of reaction was discussed. Keywords: N-Glycosides, ±-bromoglucose, Amadori rearrangement, quinazolinone