- A METHOD FOR FLUORINATED RING-OPENING OF A SUBSTRATE
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Disclosed herein, inter alia, are methods useful for making a fluoroalkyl amine and methods useful for making an α-oxygenated cyclic amine.
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Paragraph 0260; 0290; 0306
(2019/12/25)
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- Catalytic enantio- and diastereoselective alkylations with cyclic sulfamidates
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(Figure Presented) Open for business: The enantio- and diastereoselective nucleophilic ring opening of five-membered and six-membered cyclic sulfamidates under asymmetric phase-transfer catalysis is presented. A range of pro-nucleophiles have been successfully alkylated in good yields and in good to excellent enantioselectivites.
- Moss, Thomas A.,Alonso, Beatriz,Fenwick, David R.,Dixon, Darren J.
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supporting information; experimental part
p. 568 - 571
(2010/04/05)
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- Unique oxidation reaction of amides with pyridine-N-oxide catalyzed by ruthenium porphyrin: Direct oxidative conversion of N-acyl-L-proline to N-acyl-L-glutamate
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Oxidations of alkanes, alkenes, and aromatic rings with pyridine N-oxides are efficiently catalyzed by ruthenium porphyrins under mild conditions. We show here that the oxidation of N-acyl cyclic amines with RuIVtetraarylporphyrin dichloride-2,6-substituted pyridine N-oxides directly gives N-acyl amino acids in modest to good yield via oxidative C-N bond cleavage. N-Acylpyrrolidines and N-acylpiperidines were converted to N-acyl-γ-aminobutyric acids and N-acyl-δ-aminovaleric acids, respectively. This type of reaction is a novel one in which the C-N bond is cleaved selectively at the less substituted carbon. Notably, the proline residue in proline-containing peptides was selectively converted to glutamate. A large intramolecular kinetic isotope effect (kH/kD = 9.8) was observed in the oxidation of N-benzoyl[2,2,-d2]pyrrolidine, indicating that the reaction should involve an α-hydrogen atom abstraction process as the rate-determining step. N-Acylcarbaldehyde, the putative intermediate ring-opened form of α-hydroxylated N-acyl cyclic amine, was readily oxidized with the oxidizing system to afford the corresponding N-acylamino acid in good yield. Further, lactams (1-methyl-2-pyrrolidone and 1-methyl- 2-piperidone) were also oxidized to give the corresponding imides (1-methylsuccinimide and 1-methylpiperidine-2,6-dione). Copyright
- Ito, Rina,Umezawa, Naoki,Higuchi, Tsunehiko
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p. 834 - 835
(2007/10/03)
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- Niobium pentachloride-mediated nucleophilic additions to cyclic N-acyliminium ions
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Niobium chloride promoted the nucleophilic addition of allyltrimethylsilane, ethyl acetoacetate, indole and the silyl enol ether derived from acetone to cyclic N-acyliminium ions. The products were obtained in good yields.
- Kleber, Carlos,Andrade,Matos, Ricardo Alexandre F.
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p. 1189 - 1191
(2007/10/03)
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- Chemical and microsomal oxidation of tertiary amides: Regio- and stereoselective aspects
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The conformationally restricted tertiary amides N-methyl-2-pyrrolidone 6, N-methyl-2-piperidone 7 and N-methyl-ε-caprolactam 8 were oxidised by 5,10,15,20-tetraphenylporphyrinatoiron(III) chloride/tert-butyl hydroperoxide (TPPFe/ButOOH) and by phenobarbital-induced rat liver microsomes. The products were the N-demethylated lactams together with the analogous N-methylimides and norimides. For the TPPFe/ButOOH reaction ring oxidation is preferred to N-demethylation, paralleling the relative stabilities of the corresponding intermediate carbon-centred radicals as calculated by the AM1 semi-empirical method. In contrast, the microsomal reaction of the N-methyllactams strongly favours N-demethylation, demonstrating that hydrogen atom abstraction from the alkyl group Z to the amide carbonyl oxygen atom is preferred. The chiral tertiary amides N-methyl-N-(1-phenylethyl)benzamide 9 and N-methyl-5-phenyl-2-pyrrolidone 10 were also oxidised by TPPFe/ButOOH and by phenobarbital-induced rat liver microsomes. Using TPPFe/ButOOH, loss of the secondary alkyl group of 9 is preferred by a factor of ca. 6. Similarly, ring oxidation of 10 is favoured over demethylation by a factor of 9. For the microsomal reaction of (R)-9 dealkylation is preferred over demethylation by a factor of 1.7, whereas for (S)-9 demethylation is favoured by a factor of 1.25. For the microsomal reaction of (R)-10 and (S)-10 ring oxidation at the 5-position of the pyrrolidone ring is preferred over demethylation by factors of ca. 4 and 9 for the two isomers, respectively, and the (S)-enantiomer undergoes ring oxidation 2-3 times more readily than the (R)-enantiomer. For both 9 and 10 there is negligible stereochemical influence of the chiral centre upon the N-demethylation reaction. The results show that the stereochemical preference of the microsomal N-dealkylation reaction is modest.
- Iley, Jim,Tolando, Roberto,Constantino, Luis
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p. 1299 - 1305
(2007/10/03)
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- Stereocontrolled formation of epoxy peroxide functionality appended to a lactam ring
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The action of tert-butyl hydroperoxide and tin(IV) chloride upon allylic alcohols containing a lactam ring leads mainly to epoxy alkyl peroxides with high diastereoselection. Both the stereochemistry and the products formed are in marked contrast to the r
- Marson,Khan,Porter
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p. 4771 - 4775
(2007/10/03)
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- Tin(IV)-mediated stereoselective synthesis of epoxides with concomitant alkyl peroxide formation
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Epoxy alkyl peroxides are formed stereoselectively by the action of t-butyl hydroperoxide-SnCl4 upon allylic alcohols containing an amido group, and with reversal of the diastereoselectivity shown by the action of t-butyl hydroperoxide-VO(acac)2 upon analogous carbocyclic alcohols.
- Hursthouse,Khan,Marson,Porter
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p. 5979 - 5982
(2007/10/02)
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- A FACILE SYNTHESIS OF dl-SEDAMINE AND dl-ALLOSEDAMINE
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Racemic sedamine and dl-allosedamine were easily synthesized from the intermediate (3) using a cyclic acyliminium salt by the addition-elimination reaction sequence.
- Ozawa, Naganori,Nakajima, Setsuko,Zaoya, Kyoko,Hamaguchi, Fumiko,Nagasaka, Tatsuo
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p. 889 - 894
(2007/10/02)
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- Ruthenium Tetroxide Oxidation of N-Alkyllactams
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Ruthenium tetroxide (RuO4) oxidation of N-alkyllactams proceeded regioselectively depending on the size of lactam ring, except for the seven-membered ring.Four- and eight-membered N-methyl- and N-ethyllactams were oxidized at the exocyclic α-carbon adjacent to nitrogen to produce the N-acyllactams and NH-lactams, while five- and six-membered lactams underwent endocyclic oxidation to yield the cyclic imides.Oxidation of seven-membered lactams yielded a mixture of products arising from both exocyclic and endocyclic oxidations.These regioselectivities were confirmed in the oxidation of substrates having a tertiary carbon at the oxidation position.Keywords---oxidation; ruthenium tetroxide oxidation; regioselective oxidation; hydroxylation; imide synthesis; N-alkyllactam; N-acyllactams; imide; ruthenium tetroxide; two-phase method
- Yoshifuji, Shigeyuki,Arakawa, Yukimi,Nitta, Yoshihiro
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p. 357 - 363
(2007/10/02)
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