2436-29-5Relevant articles and documents
-
Bott
, p. 1304 (1969)
-
Divergent Stereocontrolled Synthesis of the Enantiopure Tetracyclic Cores of Asparagamine A and Stemofoline via an Intramolecular 2-Propylidine-1,3-(bis)silane Bicyclization
Anderson, Bryon K.,Livinghouse, Tom
, p. 9847 - 9855 (2015)
A concise and highly diastereoselective synthesis of the polyfused tetracyclic cores of the Stemona alkaloids asparagamine A and stemofoline that relies on a 2-propylidine-1,3-(bis)silane bicyclization onto a enantiodefined pyrrolidine 2,5-di(cation) equivalent derived from l-malic acid is reported. A crucial feature of this divergent synthetic approach involves the solvolysis of a transient and highly labile tertiary-propargylic hydroxylactam trifluoroacetate in the strongly ionizing medium 5 M LiClO4/Et2O. The acyliminium ion generated in this manner undergoes stereospecific interception by the aforementioned (bis)silane nucleophile.
Robust synthesis and crystal-structure analysis of 7-cyano-7-deazaguanine (PreQ0 base) and 7-(aminomethyl)-7-deazaguanine (PreQ1 base)
Klepper, Florian,Polborn, Kurt,Carell, Thomas
, p. 2610 - 2616 (2005)
We describe robust and efficient synthetic methods for the synthesis of the preQ0 and preQ1 bases, which are the biosynthetic precursors of the hypermodified RNA nucleoside queuosine. The X-ray crystal-structure analysis of preQ1 is also described.
Synthesis process of spermidine and intermediate thereof
-
Paragraph 0027-0029, (2021/10/27)
The invention provides a synthesis process of spermidine (I) which takes 3 -t-butyloxycarbonyl V (N -) and -1-t-butyloxycarbonyl 4 - IV butanediamine (N -) as a raw material to obtain the spermidine trihydrochloride (-4 - II III) by reductive amination reaction, and provides a novel method for chemical synthesis of spermidine by liberation of the protecting group from the intermediate I (3 -) to obtain the spermidine (III) II.
Organocatalytic diastereo- And enantioselective oxa-hetero-Diels-Alder reactions of enones with aryl trifluoromethyl ketones for the synthesis of trifluoromethyl-substituted tetrahydropyrans
Pasha, Maira,Tanaka, Fujie
supporting information, p. 9242 - 9250 (2021/11/16)
Tetrahydropyran derivatives are found in bioactives, and introduction of the trifluoromethyl group into molecules often improves biofunctions. Here we report diastereo- and enantioselective oxa-hetero-Diels-Alder reactions catalyzed by amine-based catalyst systems that afford trifluoromethyl-substituted tetrahydropyranones. Catalyst systems and conditions suitable for the reactions to provide the desired diastereomer products with high enantioselectivities were identified, and various trifluoromethyl-substituted tetrahydropyranones were synthesized with high diastereo- and enantioselectivities. Mechanistic investigation suggested that the reactions involve a [4 + 2] cycloaddition pathway, in which the enamine of the enone acts as the diene and the ketone carbonyl group of the aryl trifluoromethyl ketone acts as the dienophile. In this study, tetrahydropyran derivatives with the desired stereochemistry that are difficult to synthesize by previously reported methods were concisely obtained, and the range of tetrahydropyran derivatives that can be synthesized was expanded. This journal is
