252919-08-7Relevant articles and documents
TRIAZOLE-ISOXAZOLE COMPOUND AND MEDICAL USE THEREOF
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Paragraph 3413, (2016/06/06)
A compound represented by Formula [I]: or pharmaceutically acceptable salt thereof, wherein each symbol is as defined in the description.
Synthesis of tetrahydropyrazolo[1,5- C ]pyrimidine-2,7(1 H,3 H)-diones
Gro?elj, Uro?,Podlogar, Anja,Novak, Ana,Dahmann, Georg,Golobi?, Amalija,Stanovnik, Branko,Svete, Jurij
, p. 639 - 650 (2013/04/10)
A series of tetrahydropyrazolo[1,5-c]pyrimidine-2,7(1H,3H)-diones 3a-h as the first representatives of the so far unexplored saturated heterocyclic system have been synthesized, formally in 12 steps from methyl acrylate (4). The synthesis comprises a four-step preparation of methyl N-Cbz-5-alkylamino-3- oxopentanoates 9a-c, their three-step transformation into 5-{2-[(alkyl) (benzyloxycarbonyl)amino]ethyl}pyrazolidin-3-ones 12a-c, three-step selective alkylation of the amidic N-2 to give 2-alkyl-5-{2-[(alkyl)(benzyloxycarbonyl) amino]ethyl}pyrazolidin-3-ones 16b-h, followed by hydrogenolytic Cbz-deprotection and subsequent cyclization of the intermediate 1,4-diamine with CDI to furnish the title compounds 3. Most of the synthetic steps were performed as a one-pot transformation. Georg Thieme Verlag Stuttgart New York.
Asymmetric synthesis of trans-2,3-piperidinedicarboxylic acid and trans-3,4-piperidinedicarboxylic acid derivatives
Xue, Chu-Biao,He, Xiaohua,Roderick, John,Corbett, Ronald L.,Decicco, Carl P.
, p. 865 - 870 (2007/10/03)
Asymmetric syntheses of (2S,3S)-3-(tert-butoxycarbonyl)-2-piperidinecarboxylic acid (1b), (3R,4S)-4-(tert-butoxycarbonyl)-3-piperidinecarboxylic acid (2b), and their corresponding N-Boc and N-Cbz protected analogues 8a,b and 17a,b are described. Enantiomerically pure 1b has been synthesized in five steps starting from L-aspartic acid β-tert-butyl ester. Tribenzylation of the starting material followed by alkylation with allyl iodide using KHMDS produces the key intermediate 5a in a 6:1 diastereomeric excess. Upon hydroboration, the alcohol 6a is oxidized, and the resulting aldehyde 7 is subjected to a ring closure via reductive amination, providing 1b in an overall yield of 38%. Optically pure 2b has been synthesized beginning with N-Cbz-β-alanine. The synthesis involves the induction of the first stereogenic center using Evans's chemistry and sequential LDA-promoted alkylations with tert-butyl bromoacetate and allyl iodide. Further elaboration by ozonolysis and reductive amination affords 2b in an overall yield of 28%.
