- Practical Preparation of K-252a from a Fermentation Solution
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We developed a practical preparation procedure for K-252a by methylating K-252b on an industrial scale. The water-insoluble K-252a, which was present in the cell mass, was converted to the water-soluble K-252b Na salt in an alkaline solution. The obtained K-252b was methylated with dimethylsulfate in the presence of potassium carbonate in dimethylacetamide. We have already used this method to manufacture 90 kg of K-252b from the fermentation broth, and regenerated 65 kg of K-252a from K-252b.
- Kino, Mitsutaka,Shono, Kenzo,Nishimura, Tetsuo,Nagamura, Satoru
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Read Online
- COMPOUNDS FOR IMMUNOPOTENTIATION
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Methods of stimulating an immune response and treating patients responsive thereto with 3,4-di(1H-indol-3-yl)-1H-pyrrole-2,5-diones, staurosporine analogs, derivatized pyridazines, chromen-4-ones, indolinones, quinazolines, nucleoside analogs, and other small molecules are disclosed.
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Page/Page column 139
(2010/02/15)
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- Synthesis, modeling, and in vitro activity of (3′S)-epi-K-252a analogues. Elucidating the stereochemical requirements of the 3′-sugar alcohol on trkA tyrosine kinase activity
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Utilizing our recently published semisynthetic approach to the (3′S)-K-252a diastereomer, we report the first synthesis of the (3′R)-10 diastereomer and a set of related epimers, with the goal of defining the Stereochemical role of the 3′-sugar hydroxyl g
- Gingrich, Diane E.,Yang, Shi X.,Gessner, George W.,Angeles, Thelma S.,Hudkins, Robert L.
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p. 3776 - 3783
(2007/10/03)
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- Preparation of K-252a
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The present invention provides a process for the synthesis of K-252a and intermediates useful in the process.
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Page column 7
(2008/06/13)
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- Synthesis and kinase inhibitory activity of 3′-(S)-epi-K-252a
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The 3′-epi diastereomer of K-252a was synthesized with the goal of evaluating the stereochemical requirements of the 3′-sugar alcohol on kinase inhibitory activity. Inverting the 3′-alcohol resulted in a 20 nM inhibitor of VEGFR2 and a 1 nM inhibitor of TrkA tyrosine kinase.
- Gingrich, Diane E.,Hudkins, Robert L.
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p. 2829 - 2831
(2007/10/03)
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- Design and implementation of an efficient synthetic approach to furanosylated indolocarbazoles: Total synthesis of (+)- and (-)-K252a
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The first total synthesis of the natural product (+)-K252a (2) has been achieved in 12 steps from commercially available materials, with a longest linear sequence of seven steps and an overall yield of 21%. The synthetic strategy employs novel rhodium carbenoid chemistry in the construction of both the indolocarbazole aglycon (4) and the carbohydrate moiety (9).
- Wood, John L.,Stoltz, Brian M.,Dietrich, Hans-Jürgen,Pflum, Derek A.,Petsch, Dejah T.
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p. 9641 - 9651
(2007/10/03)
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- The Total Synthesis of (+/-)K252a
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The total synthesis of (+/-)K252a (1) has been achieved following a convergent approach in which an acid-catalyzed bis-glycosidation reaction serves as a key step.
- Lowinger, Timothy B.,Chu, Jingxi,Spence, Patrick L.
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p. 8383 - 8386
(2007/10/02)
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