Efficient synthesis of heterocyclic compounds using ethenetricarboxylic acid diesters.
Ethenetricarboxylic acid diester 1a is a useful compound bearing two reactive sites, a CO2H group and a Michael acceptor. Reactions of 1a and reagents with oxygen and nitrogen nucleophilic moieties have been examined. The reaction of 1a with 2-aminoalcohols in the presence of EDCI and HOBt in one pot gave N,O-containing heterocyclic compounds, regioselectively. The stepwise method has also been carried out. Deprotection of N-Boc protected aminoesters, followed by basic aqueous workup, gave various 1,4-oxazine derivatives. Deprotection of the O-TBS protected amides also leads to spontaneous cyclization and affords 1,4-oxazine derivatives. They have the opposite regiochemistry to those from the one-pot reaction. Thus, both ester or amide regioisomers can be prepared. These synthetic methods represent a new general strategy for the construction of diverse heterocyclic systems such as morpholine-derived heterocycles.
Yamazaki
Shoko
S
Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8528, Japan. yamazaks@nara-edu.ac.jp
Iwata
Yuko
Y
Fukushima
Yugo
Y
D000577:Amides / Q000737:chemistry; D004952:Esters / Q000737:chemistry; D005030:Ethylenes / Q000737:chemistry; D006571:Heterocyclic Compounds / Q000138:chemical synthesis*; D014233:Tricarboxylic Acids / Q000737:chemistry*
D000577:Amides; D004952:Esters; D005030:Ethylenes; D006571:Heterocyclic Compounds; D014233:Tricarboxylic Acids