Methyl and Phenylmethyl 2-Acetyl-3-{[2-(dimethylamino)-1-(methoxycarbonyl)ethenyl]amino}prop-2-enoate in the Synthesis of heterocyclic systems: Preparation of 3-amino-4H-pyrido-[1,2-a]pyrimidin-4-ones

✍ Scribed by Lovro Selič; Simona Golič Grdadolnik; Branko Stanovnik

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: German
• Weight: 468 KB
• Volume: 80
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19970800811

✦ Synopsis

Methyl 2-acetyl-3-{[2-(dimethylamino)-1-(methoxycarbonyl)ethenyl]amino}prop-2-enoate (4) and phenylmethyl 2-acetyl-3-{[2-(dimethyIamino)-l -(methoxycarbonyl)ethenyl]amino}prop-2-enoate (5) were prepared in three steps from the corresponding acetoacetic esters, and used as reagents for the preparation of N3-protected 3-amino-4H-pyrido[l,2-a]pyrimidin-4-ones 10-12, 5H-thiazolo[3,2-a]pyrimidin-5-one 13, 4H-pyrido[l,Z-a]pyridin-4-one 19 and 2H-1-benzopyran-2-ones 20-23. Free 3-amino-4H-pyrido[l,2-a]pyrimidin-4-ones 24-26 were prepared from 10-12 by removal of the 2-(methoxycarbonyl)-3-oxobut-l-enyl or 3-oxo-2-[(phenylmethoxy)carbonyl]but-I-enyl as N-protecting group by various methods.