1604-01-9Relevant articles and documents
Characterization of three novel enzymes with imine reductase activity
Gand,Müller,Wardenga,H?hne
supporting information, p. 126 - 132 (2015/02/19)
Imine reductases (IRED) are promising catalysts for the synthesis of optically pure secondary cyclic amines. Three novel IREDs from Paenibacillus elgii B69, Streptomyces ipomoeae 91-03 and Pseudomonas putida KT2440 were identified by amino acid or structural similarity search, cloned and recombinantly expressed in E. coli and their substrate scope was investigated. Besides the acceptance of cyclic amines, also acyclic amines could be identified as substrates for all IREDs. For the IRED from P. putida, a crystal structure (PDB-code 3L6D) is available in the database, but the function of the protein was not investigated so far. This enzyme showed the highest apparent E-value of approximately Eapp = 52 for (R)-methylpyrrolidine of the IREDs investigated in this study. Thus, an excellent enantiomeric purity of >99% and 97% conversion was reached in a biocatalytic reaction using resting cells after 24 h. Interestingly, a histidine residue could be confirmed as a catalytic residue by mutagenesis, but the residue is placed one turn aside compared to the formally known position of the catalytic Asp187 of Streptomyces kanamyceticus IRED.
Stereodivergent diversity oriented synthesis of piperidine alkaloids
Adriaenssens, Louis V.,Austin, Carolyn A.,Gibson, Mairi,Smith, David,Hartley, Richard C.
, p. 4998 - 5001 (2007/10/03)
Alkylidenetitanium reagents enable the reagent-controlled high throughput asymmetric synthesis of 2-substituted piperidines and rapid access to multiple cyclic imines using solid phase synthesis (SPS). The Schrock carbenes, generated by reduction of thioacetals, convert resin-bound esters into enol ethers. Treatment with acid releases amino ketones that are cyclized with TMSCl to give iminium salts. Reduction introduces a chiral centre at C-2, whose absolute stereochemistry is determined by a phenethylamine (PEA) chiral auxiliary. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Use of group 4 Bis(sulfonamido) complexes in the intramolecular hydroamination of alkynes and allenes
Ackermann, Lutz,Bergman, Robert G.,Loy, Rebecca N.
, p. 11956 - 11963 (2007/10/03)
Titanium tetrakis(amido) complexes catalyze the intramolecular hydroamination of alkynes and allenes more efficiently than Cp-based species. We report here that electron-withdrawing and sterically demanding bis(sulfonamido) ligands lead to enhanced catalytic activity. Zirconium analogues have also been prepared, and the tosyl-substituted complex 20 has been structurally characterized. As in the titanium series, bis(sulfonamido) zirconium catalysts are more efficient in the intramolecular hydroamination of allenes than bis(cyclopentadienyl) complex Cp2ZrMe2 (23). Furthermore, these compounds transform 1,3-disubstituted aminoallenes with high stereoselectivity to the Z-allylamines and allow the hydroamination of a trisubstituted allene. Titanium bis(sulfonamido) imido complex 27 was synthesized. It converts aminoallene 10 to cylic imine 11 with a rate comparable to that of tetrakis(amide) 15, supporting the hypothesis of a catalytically active titanium imido intermediate.
Short Enantioselective Total Syntheses of the Piperidine Alkaloids (S)-Coniine and (2R,6R)-trans-Solenopsin A via Catalytic Asymmetric Imine Hydrosilylation
Reding, Matthew T.,Buchwald, Stephen L.
, p. 6344 - 6347 (2007/10/03)
The enantioselective syntheses of (S)-coniine and (2R,6R)-trans-solenopsin A are reported. The key step in both syntheses is the catalytic asymmetric hydrosilylation of a cyclic imine.
DNA-damaging steroidal alkaloids from Eclipta alba from the suriname rainforest
Abdel-Kader, Maged S.,Bahler, Brian D.,Malone, Stan,Werkhoven, Marga C. M.,Van Troon, Frits,David,Wisse, Jan H.,Bursuker, Isia,Neddermann, Kim M.,Mamber, Stephen W.,Kingston, David G. I.
, p. 1202 - 1208 (2007/10/03)
Bioassay-guided fractionation of the MeOH extract of Eclipta alba using three yeast strains (1138, 1140, and 1353) resulted in the isolation of eight bioactive steroidal alkaloids (1-8), six of which are reported for the first time from nature. The major alkaloid was identified as (20S)(25S)-22,26- imino-cholesta-5,22(N)-dien-3β-ol (verazine, 3), while the new alkaloids were identified as 20-epi-3-dehydroxy-3-oxo-5,6-dihydro-4,5-dehydroyerazine (1), ecliptalbine [(20R)-20-pyridyl-cholesta-5-ene-3β,23-diol] (4), (20R)- 4β-hydroxyverazine (5), 4β-hydroxyverazine (6), (20R)-25β-hydroxyverazine (7), and 25β-hydroxyverazine (8). Ecliptalbine (4), in which the 22,26- imino ring of verazine was replaced by a 3-hydroxypyridine moiety, had comparable bioactivity to verazine in these assays, while a second alkaloid (8) showed good activity against Candida albicans. All the alkaloids showed weak cytotoxicity against the M-109 cell line.
Regioselective oxyfunctionalization of unactivated tertiary and secondary C-H bonds of alkylamines by methyl(trifluoromethyl)dioxirane in acid medium
Asensio, Gregorio,González-Nú?ez, María Elena,Bernardini, Carmen Boix,Mello, Rossella,Adam, Waldemar
, p. 7250 - 7253 (2007/10/02)
Tetrafluoroborate salts of primary, secondary, and tertiary alkylamines are resistant toward N oxidation by methyl(trifluoromethyl)dioxirane (1b), which allows the selective oxidation of aliphatic tertiary and secondary C-H bonds in the alkyl side chain. The oxidations are carried out at 0°C with a ketone-free solution of methyl(trifluoromethyl)-dioxirane (1b) in methylene chloride. By this procedure, within 3 h the tertiary C-H bonds of acyclic, cyclic, and polycyclic amines 2a-e are hydroxylated to give the corresponding amino alcohols 3a-e. In the case of the acyclic amines 2a,b longer reaction times were necessary, and in the strong acid medium the corresponding amino acetamides 4a,b were obtained through Ritter reaction with the solvent acetonitrile. The strong electron-withdrawing nature of the ammonium group deactivates the oxidation of even tertiary C-H bonds at the α and β positions. Secondary C-H bonds of the linear aliphatic primary amines 2f-h were oxidized exclusively at the ∈ position to give the 2,3,4,5-tetrahydro-6-alkylpyridines 6f-h after intramolecular condensation of the corresponding amino ketones 5f-h.
Palladium-Catalyzed Intramolecular Addition of Amines to Acetylenes. Synthesis of Cyclic Imines
Fukuda, Yukitoshi,Matsubara, Seijiro,Utimoto, Kiitiro
, p. 5812 - 5816 (2007/10/02)
Intramolecular aminopalladation of alkynylamines gave intermediary alkenylpalladium compounds that hydrolyzed and isomerized to thermodynamically stable cyclic imines.Treatment of 3-alkynylamines with a catalytic amount of PdCl2(MeCN)2 gave exclusively 1-
Preparation of 2,3,4,5-tetrahydropyridines from 5-alkynylamines under the catalytic action of gold(III) salts
Fukuda,Utimoto
, p. 975 - 978 (2007/10/02)
Intramolecular addition of amine to carbon-carbon triple bonds in 5-alkynylamines produces 2,3,4,5-tetrahydropyridines under the catalytic action of an aurate salt. Some venom components of various ant species are synthesized by the application of this re
Organometallic Ring-Opening Reactions of N-Acyl and N-Alkoxycarbonyl Lactams. Synthesis of Cyclic Imines
Giovannini, Arianna,Savoia, Diego,Umani-Ronchi, Achille
, p. 228 - 234 (2007/10/02)
The reactions of hexyl- and phenylmagnesium bromides with N-acyl and N-alkoxycarbonyl lactams in tetrahydrofuran at -78 deg C have been performed to determine the factors affecting the regioselectivity.N-Pivaloyl γ- and δ-lactams undergo the ring-opening reactions with both Grignard reagents, whereas on the N-benzoyl γ-lactam a complete selectivity is achieved only with phenylmagnesium bromide.The N-Cbz γ- and δ-lactams preferentially react at the exocyclic carbonyl group, especially with hexylmagnesium bromide.The N-Boc five- to eight-membered lactams undergo the ring-opening reaction to give N-Boc-ω-amino ketones, although the efficiency slightly decreases by increasing the ring size.The deprotection of the N-Boc-ω-amino ketones with trifluoroacetic acid easily affords the corresponding five- to seven-membered cyclic imines.Pyridine alkaloids containing the cyclic imine moiety have been prepared by a modified route, exploiting the more easily available pyridyllithium reagents, instead of the corresponding Grignard reagents.
