- Regioselectivity in Nucleophilic Ring Opening of 2-Methylaziridines. Lag of Bond Making as Model for the Abnormal Opening
-
The regioselectivity ratio RS=normal:abnormal opening of activated 2-methylaziridines 2 by nucleophiles is found to range from 0.10 to unmeasurable large (only normal opening=substitution at CH2 by strongly basic carbanions).RS is assumed to result from SN2 variants differing in the degree to which bond breaking is ahead of bond making including perhaps synchronous SN2.Bond breaking will be more ahead for the N-CMe bond.High nucleophilic power pushes bond making toward a synchronous process resulting in great RS.The decrease in RS with acyl activation relative to sulfonyl activation is in accord with a flattening of the nitrogen pyramid (planarization effect).The planarization effect is retained in acidic medium by O-protonation: RS 0.10-0.14 for methanolysis as compared to RS 0.43 for N-protonated sulfonylaziridine 2h.AM1 calculations support the planarization hypothesis. - No indication for SET with trityl anion was found.
- Lin, Pen-Yuan,Bentz, Gunther,Stamm, Helmut
-
-
Read Online
- UV-Light-Induced N-Acylation of Amines with α-Diketones
-
Herein, we develop a mild method for N-acylation of primary and secondary amines with α-diketones induced by ultraviolet (UV) light. Forty-six examples with various functional groups are explored at room temperature with irradiation by three 26 W UV lamps (350-380 nm). The yield reaches 97%. The gram scale experiment product yield is 76%. Moreover, this system can be applied to the synthesis of several amino acid derivatives. Mechanistic studies show that benzoin is generated in situ from benzil under UV irradiation.
- Xu, Zhihui,Yang, Tianbao,Tang, Niu,Ou, Yifeng,Yin, Shuang-Feng,Kambe, Nobuaki,Qiu, Renhua
-
supporting information
p. 5329 - 5333
(2021/07/21)
-
- N-Acyl-N-(4-chlorophenyl)-4-nitrobenzenesulfonamides: Highly selective and efficient reagents for acylation of amines in water
-
A variety of N-acyl-N-(4-chlorophenyl)-4-nitrobenzenesulfonamides (1a-e) were synthesized in one pot from 4-chloroaniline under solvent-free conditions and have been developed as chemoselective N-acylation reagents. Selective protection of primary amines in the presence of secondary amines, acylation of aliphatic amines in the presence of aryl amines, and monofunctionalization of primary-secondary diamines as well as selective N-acylation of amino alcohols using these reagents are described. All of the acylation reactions were carried out in water as a green solvent. High stability and easy preparation of these acylating reagents are other advantages of this method.
- Ebrahimi, Sara,Saiadi, Safoura,Dakhilpour, Simin,Mirsattari, Seyed Nezamoddin,Massah, Ahmad Reza
-
-
- Transition metal and base free synthesis of 2-aryl-2-oxazolines from aldehydes and β-amino alcohols catalysed by potassium iodide
-
Synthesis of 2-aryl-2-oxazolines from β-amino alcohols and aldehydes was achieved in good to excellent yield by employing a potassium iodide (KI)-tert-butyl hydroperoxide (TBHP) catalytic system. This protocol is very mild, metal and base free and can be performed under ambient reaction conditions. This oxidative cyclization strategy was further extended for the synthesis of optically active 2-oxazolines, which can act as very useful chiral auxiliaries and as ligands. This journal is
- Uma Maheswari,Sathish Kumar,Venkateshwar
-
p. 39897 - 39900
(2015/02/18)
-
- A novel, facile route to β-fluoroamines by hydrofluorination using superacid HF-SbF5
-
A range of unsaturated amines and sulfonamides were converted to β-fluoro nitrogen analogues after hydrofluorination in superacid HF-SbF5, based on the formation of highly reactive electrophilic intermediates. The Royal Society of Chemistry.
- Thibaudeau, Sebastien,Martin-Mingot, Agnes,Jouannetaud, Marie-Paule,Karam, Omar,Zunino, Fabien
-
p. 3198 - 3200
(2008/02/13)
-
- INDANE DERIVATES AS MUSCARINIC RECEPTOR AGONISTS
-
The present invention relates to compounds of Formula I: I which are agonists of the M-1 muscarinic receptor.
- -
-
-
- Antidiabetic agents
-
The present invention provides compounds of Formula (I): wherein A, X, Q, Y, B, D, Z, and E have any of the values defined in the specification, and pharmaceutically acceptable salt thereof, that are useful as antidiabetic agents. Also disclosed are pharmaceutical compositions comprising one or more compounds of Formula I, processes for preparing compounds of Formula I, and intermediates useful for preparing compounds of Formula I.
- -
-
-
- Ruthenium-catalyzed oxidations for selective syntheses of ketones and acyl cyanides. Selective acylation of amino compounds with acyl cyanides
-
Oxidation of alcohols to the corresponding carbonyl compounds with tert-butyl hydroperoxide in the presence of dichlorotris(triphenylphosphine)ruthenium catalyst gives the corresponding carbonyl compounds with high efficiency. This method can be applied to the oxidation of cyanohydrins to give acyl cyanides which are versatile synthetic intermediates. Acylation of amino compounds with acyl cyanides thus obtained proceeds chemoselectively. Thus, the reaction of amino alcohols with acyl cynides gives N-acylated products exclusively. In the similar N-acylation of polyamines primary amines are selectively acylated in the presence of secondary amines. These reactions are highly useful for the synthesis of spermidine and spermine alkaloids such as spermidine alkaloids such as spermidine siderophores. Dimeric cyclocoupling reaction of diacyl cyanides such as iso- and terephthaloyl cyanides with polyamines can be performed under the similar reaction conditions to give the corresponding polyazamacrocycles with high efficiency.
- Murahashi,Naota
-
p. 433 - 440
(2007/10/02)
-
- A novel electrochemical method for benzoylation of aminoalcohols with methyl benzoates at room temperature
-
A novel electrochemical method of benzoylating aminoalcohols 2 by use of methyl benzoates 1 at room temperature was developed. 2-Aminoethanols 2 (n=0, R3=H) and 3-aminopropanols 2 (n=1, R3=H) gave the corresponding benzamides 4, as a result of electrochemical transesterification followed by O,N-acyl migration.In contrast, o- and m-aminobenzylalcohols (7a and 7b) and trans-4-(aminomethyl)cyclohexanemethanol (8a) afforded the corresponding benzoic esters, since their acyl migration is hindered.A local anesthetic, procaine, was prepared by using this electrochemical reaction.A mechanism for electrochemical transesterification, which involves a formation of alcoholate anion by a one-electron reduction of alcohol, is presented.
- Arai, Kenji,Tamura, Shohei,Masumizu, Tatsuya,Kawai, Ken-Ichi,Nakajima, Shoichi,Ueda, Akira
-
p. 903 - 907
(2007/10/02)
-
- Catalytic oxidation-reduction hydration of olefin with molecular oxygen in the presence of bis(1,3-diketonato)cobalt(II) complexes
-
In the presence of a bis(1,3-diketonato)cobalt(II) complex, various olefins are converted to the corresponding hydrated products according to the Markownikov rule on treatment with molecular oxygen in secondary alcohol (''oxidation-reduction hydration''). Removal of water formed during the hydration reaction, especially by azeotropic method, is remarkably effective to improve yields of the hydrated products based on the cobalt(II) catalyst as bis(trifluoroacetylacetonato)cobalt(II) (Co(tfa)2) or bis(2-ethoxycarbonyl-3-oxobutanalato)-cobalt(II) (Co(ecbo)2).
- Kato,Yamada,Takai,Inoki,Isayama
-
p. 179 - 186
(2007/10/02)
-
- BIS(TRIFLUOROACETYLACETONATO)COBALT(II) CATALYZED OXIDATION-REDUCTION HYDRATION OF OLEFINS SELECTIVE FORMATION OF ALCOHOLS FROM OLEFINS
-
Various olefins are hydrated with molecular oxygen (oxidant) and a secondary alcohol (reductant) in the presence of a catalytic amount of bis(trifluoroacetylacetonato)cobalt(II) in good yields
- Inoki, Satoshi,Kato, Koji,Takai, Toshihiro,Isayama, Shigeru,Yamada, Tohru,Mukaiyama, Teruaki
-
p. 515 - 518
(2007/10/02)
-
- Hydration of Olefins with Molecular Oxygen and Triethylsilane Catalyzed by Bis(trifluoroacetylacetonato)cobalt(II)
-
In the presence of a catalytic amount of bis(trifluoroacetylacetonato)cobalt(II), various olefins react smoothly with molecular oxygen (oxidant) and triethylsilane (reductant) to afford the corresponding alcohols regioselectively in good yields along with ketones.
- Isayama, Shigeru,Mukaiyama, Teruaki
-
p. 569 - 572
(2007/10/02)
-
- Oxidation-Reduction Hydration of Olefins with Molecular Oxygen and 2-Propanol Catalyzed by Bis(acetylacetonato)cobalt(II)
-
In the presence of a catalytic amount of bis(acetylacetonato)cobalt(II), various olefins are hydrated with oxygen and secondary alcohol to afford the corresponding alcohols together with alkanes and ketones via Oxidation-Reduction process.Effect of additives in the present hydration reaction shows that 2,6-lutidine and 2-picoline inhibit the production of alkanes in a large extent to result in the better yielding of alcohols.
- Mukaiyama, Teruaki,Isayama, Shigeru,Inoki, Satoshi,Kato, Koji,Yamada, Tohru,Takai, Toshihiro
-
p. 449 - 452
(2007/10/02)
-
- ELECTROCHEMICAL AMIDATION OF ESTERS
-
Amidation reactions between ester and amine, both aliphatic and aromatic, which do not happen non-electrochemically at room temperature, took place merely by passing electric current in cathodic compartment.
- Arai, Kenji,Shaw, Chu-hei,Nozawa, Koohei,Kawai, Ken-ichi,Nakajima, Shoichi
-
p. 441 - 442
(2007/10/02)
-