42457-10-3Relevant articles and documents
Continuous-flow oxidative cyanation of primary and secondary amines using singlet oxygen
Ushakov, Dmitry B.,Gilmore, Kerry,Kopetzki, Daniel,McQuade, D. Tyler,Seeberger, Peter H.
supporting information, p. 557 - 561 (2014/01/23)
Primary and secondary amines can be rapidly and quantitatively oxidized to the corresponding imines by singlet oxygen. This reactive form of oxygen was produced using a variable-temperature continuous-flow LED-photoreactor with a catalytic amount of tetraphenylporphyrin as the sensitizer. α- Aminonitriles were obtained in good to excellent yields when trimethylsilyl cyanide served as an insitu imine trap. At 25°C, primary amines were found to undergo oxidative coupling prior to cyanide addition and yielded secondary α-aminonitriles. Primary α-aminonitriles were synthesized from the corresponding primary amines for the first time, by an oxidative Strecker reaction at -50 °C. This atom-economic and protecting-group-free pathway provides a route to racemic amino acids, which was exemplified by the synthesis of tert-leucine hydrochloride from neopentylamine. The mild synthesis of imines paves the way to aminonitriles and amino acids. Aerobic oxidation of primary and secondary amines in a continuous photoreactor with singlet oxygen generated insitu led to the rapid formation of imines, which were quantitatively trapped as α-aminonitriles (see scheme; TMS=trimethylsilyl). Benzylic and primary α-aminonitriles, precursors for amino acids, could be efficiently produced in three minutes.
A new and efficient synthesis of derivatives of octahydro-4H-pyrrolo[1,2-c] pyrido[1′,2′-a]imidazole
Rouchaud, Anne,Braekman, Jean-Claude
, p. 2346 - 2353 (2011/06/22)
When diethyl malonate was added to a solution of Δ1- piperideine, generated in situ by oxidative desamination and decarboxylation of L-lysine by N-bromosuccinimide (NBS), formation of the unexpected tricyclic compound 6 (4-diethylmalonyl-octahydro-4H-pyrrolo[1,2-c]pyrido[1′, 2′-a]imidazole)was observed. The structure of 6 was deduced from analysis of its spectroscopic data and was confirmed both by chemical degradation and by total synthesis. We proved that 3-bromo-1-piperideine was implicated in its formation. Moreover, based on this feature, a new and efficient synthesis of 6 was developed. The elaborated pathway was adapted to access derivatives related to 6 that differed in their C-4 substituent. A new and efficient synthesis of derivatives of the tricyclic heterocycle A from lysine is described. A mechanism involving 3-halopiperideines as intermediates and based on a ring contraction followed by Michael reaction is proposed and tested. Copyright
A Convenient Synthesis of 6-Acetyl-1,2,3,4-tetrahydropyridine, the Principle Bread Flavor Component
Kimpe, Norbert De,Stevens, Christian
, p. 2904 - 2906 (2007/10/02)
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