- Cycloaddition of Acylnitroso Compounds and Nitrosobenzene with the Pyrrolidine Dienamine of Pummerer's Ketone: X-Ray Crystal Structure of a Bridged 1,2-Oxazine Derivative
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When the pyrrolidine dienamine 2 of Pummerer's ketone 1 was treated with nitrosocarbonylmethane 4, generated in situ by periodate oxidation of acetohydroxamic acid, the major product was a bridged 1,2-oxazine, shown to have the structure 10 by X-ray cryst
- Freer, Andrew A.,Islam, Md. Azizul,Kirby, Gordon W.,Mahajan, Mohinder P.
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p. 1001 - 1007
(2007/10/02)
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- BIOGENESIS-LIKE TRANSFORMATION OF SALIDROSIDE TO RENGYOL AND ITS RELATED CYCLOHEXYLETANOIDS OF FORSYTHIA SUSPENSA
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Photooxygenation of salidroside (8) in methanol in presence of Rose Bengal afforded cornoside (9), which, on high pressure hydrogenation with 5percent palladium on activated carbon, yielded rengyoside B (6).Reduction of 6 with sodium borohydride gave rengyoside A(5) stereoselectively.By enzymatic hydrolysis, 9, 6 and 5 furnished rengyolone (4), rengyoxide (3) and rengyol (1), respectively. Similerly, p-hydroxyphenylethanol (10), the aglycone part of salidroside (8), was oxygenated photochemically to a dienone alcohol, which cyclized spontaneously to rengyolone (4).Hallerone (17) was obtained by the photooxygenation of p-hydroxyphenylethyl acetate (10b).Thus the plausible biosynthetic routes from salidroside (8) to rengyol (1) and the related natural cyclohexylethanoids were simulated chemically.
- Endo, Katsuya,Seya, Kazuhiko,Hikino, Hiroshi
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p. 3673 - 3682
(2007/10/02)
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