Synthesis and Structures of 6-Aryl-1,5-dimethoxycarbonyl-2-methyl-4-morpholino-1,3-cyclohexadienes and Related Compounds

Autor: Koichi Takimoto, Ikuo Ueda, Hajime Nitta
Rok vydání: 1992
Předmět:
Zdroj: Chemical and Pharmaceutical Bulletin. 40:858-863
ISSN: 1347-5223
0009-2363
Popis: Reaction of benzaldehyde (1a) with methyl acetoacetate (2) in the presence of morpholine (or piperidine) and AcOH in refluxing C6H6 yielded a new condensation product, 1, 5-dimethoxycarbonyl-2-methyl-4-morpholino (or piperidino)-6-phenyl-1, 3-cyclohexadiene (3a or 10a), along with a usual product, benzylideneacetoacetate (4a). Under the conditions determined as optimum, 3a was prepared in 86% yield. However, reaction of 1a and 2 in the presence of morpholine (or piperidine) in EtOH solution yielded 4a, a poly-substituted cyclohexanone derivative (5a) and a cyclohexenone derivative (7a), while the production of 3a was not detected. Compound 3a (or 10a) was also prepared by an alternative procedure of condensation of 5a or 6a with morpholine (or piperidine) in the presence of TiCl4. Compound 6a was prepared by dehydration of 5a under acidic conditions. Acid hydrolysis of 3a afforded 6'a, which is the C-4 epimer of 6a. The configurations of 3a, 6a and 6'a were assigned on the basis of the proton nuclear magnetic resonance (1H-NMR) spectra. Mechanisms of the formation of 3a are discussed. Some of 3 and related compounds exhibited potent calcium channel-blocking activity.
Databáze: OpenAIRE