Grignard additions to a quinoxalinium salt were studied. Depending on the ratio of the reagents and reaction temperature, 1, 2, 3, 4-tetrahydroquinoxaline and 1, 2-dihydroquinoxaline derivatives could be resulted sele...Grignard additions to a quinoxalinium salt were studied. Depending on the ratio of the reagents and reaction temperature, 1, 2, 3, 4-tetrahydroquinoxaline and 1, 2-dihydroquinoxaline derivatives could be resulted selectively.展开更多
To investigate the recovery of amino alcohols as chiral auxiliaries, optically active p-benzyloxyphenylglycinol and its corresponding oxazolidine of 1-naphthylcarboxaldehyde were prepared. Grignard additions to the ox...To investigate the recovery of amino alcohols as chiral auxiliaries, optically active p-benzyloxyphenylglycinol and its corresponding oxazolidine of 1-naphthylcarboxaldehyde were prepared. Grignard additions to the oxazolidine followed by electrophilic quench and acidic hydrolysis afforded an aldehyde(compound 8)(later it was reduced to an alcohol, compound 9) in an excellent enantiomeric excess and a good recovery of the chiral amino alcohol. This research provides a model study of chiral amino alcohols in solid phase asymmetric synthesis.展开更多
The reaction of ethyl esters of 4-methyl-2-oxo-2H-l-benzo (naphtho)pyran-3-carboxylic acids (1) with aromatic aldehydes in the presence of piperidine yielded4-styryl-3-carboxami-dopiperidyl coumarin derivatives 4. The...The reaction of ethyl esters of 4-methyl-2-oxo-2H-l-benzo (naphtho)pyran-3-carboxylic acids (1) with aromatic aldehydes in the presence of piperidine yielded4-styryl-3-carboxami-dopiperidyl coumarin derivatives 4. The reaction of hydrazine hydrate with 1gave acetophenone hydrozone derivatives 5 and acetophenone azine derivatives 6. The reaction of 1with primary amines afforded compounds 7―9. And the treatment of la with Grignard reagents afforded3-aroyl-4-methyl coumarin derivatives 10.展开更多
文摘Grignard additions to a quinoxalinium salt were studied. Depending on the ratio of the reagents and reaction temperature, 1, 2, 3, 4-tetrahydroquinoxaline and 1, 2-dihydroquinoxaline derivatives could be resulted selectively.
文摘To investigate the recovery of amino alcohols as chiral auxiliaries, optically active p-benzyloxyphenylglycinol and its corresponding oxazolidine of 1-naphthylcarboxaldehyde were prepared. Grignard additions to the oxazolidine followed by electrophilic quench and acidic hydrolysis afforded an aldehyde(compound 8)(later it was reduced to an alcohol, compound 9) in an excellent enantiomeric excess and a good recovery of the chiral amino alcohol. This research provides a model study of chiral amino alcohols in solid phase asymmetric synthesis.
文摘The reaction of ethyl esters of 4-methyl-2-oxo-2H-l-benzo (naphtho)pyran-3-carboxylic acids (1) with aromatic aldehydes in the presence of piperidine yielded4-styryl-3-carboxami-dopiperidyl coumarin derivatives 4. The reaction of hydrazine hydrate with 1gave acetophenone hydrozone derivatives 5 and acetophenone azine derivatives 6. The reaction of 1with primary amines afforded compounds 7―9. And the treatment of la with Grignard reagents afforded3-aroyl-4-methyl coumarin derivatives 10.