26977-07-1

Upstream product

• 79913-35-2 3,6-diphenyl-5,6-dihydro-4H-[1,2]oxazine 
• 56139-59-4 4-oxo-4-phenyl-butyraldehyde 
• 98-95-3 nitrobenzene 
• 62-53-3 aniline 
• 83-25-0 N-phenylmaleimide 
• 1955-39-1 5-phenyl-3H-furan-2-one 
• 3240-29-7 1-Phenylpent-4-en-1-one 
• 17649-94-4 N-phenyl 3-benzoylpropionamide 
• 55467-95-3 N-(3-chloropropyl)-benzeneamine 

Relevant academic research and scientific papers

N-phenyl-substituted pyrrolidines, piperidines and azabicyclics by a tandem reduction-double reductive amination reaction

N-Phenyl-substituted pyrrolidines and piperidines have been synthesized by catalytic reduction of nitrobenzene in the presence of 4- and 5-oxoaldehydes, respectively. The process involves reduction of the aromatic nitro group to give the N-phenylhydroxylamine or aniline followed by reductive amination with the two carbonyl functional groups. Monocyclic systems are generally formed in high yield and are easily purified. The method has also been extended to the synthesis of fused N-phenylazabicyclics from 2-(3-oxopropyl)cycloalkanones. A high degree of diastereoselectivity for the trans-fused product is observed in substrates having an ester group α to the cycloalkanone carbonyl. Bicyclic precursors lacking this ester group give mixtures of cis and trans products. Finally, contrary to previous reports, we have demonstrated that aniline can be substituted for nitrobenzene in these reactions.

4,4'-Di-tert-butylbiphenyl-Catalysed Reductive Opening of Azetidines with Lithium: A Direct Preparation of 3,N-Dilithioalkylamines

The reaction of N-phenylazetidine 1a with an excess of lithium powder and a catalytic amount of 4,4'-di-tert-butylbiphenyl (5 molpercent) in THF at -15 deg C leads to the corresponding dianion 2a, which by treatment with different electrophiles (H2O, D2O, ButCHO, PhCHO, (CH2)5CO, PhCH=NPh, CO2) yields, after hydrolysis with water, the expected functionalysed amines 3aa-ah.The same method applied to N-isopropyl-2-phenylazetidine 1c affords compounds 3ca-ce (electrophiles: H2O, D2O, PhCHO, Me2CO, CH2=CHCH2Br) resulting from the more stable benzylic intermediate 2c.Finally, the regiochemistry in the reductive opening of 2-methyl-N-phenylazetidine 1d followed by deuterolysis was studied: a mixture of both regioisomers 3da+3da' was obtained, the ratio being the oposite as expected according to the stability of both intermediates 2d and 2d'.

Reductive Transformations of 5,6-Dihydro-4H-1,2-oxazines: Synthesis of 4-Hydroxy Ketoximes, N-Hydroxypyrrolidine Derivatives, and Other Nitrogen-Containing Compounds

6-Siloxy-substituted 1,2-oxazines 1 are transformed into 4-hydroxy ketoximes 2 by reduction with NaBH4 in ethanol.Reductive Beckmann rearrangement converts the oxime 2a into the 1,4-amino alcohol 7.Diisobutylaluminum hydride (DIBAH) induces a novel reductive ring contraction of 1 to provide either N-hydroxypyrrolidine derivatives 8 or nitrones 9.Other 1,2-oxazines lacking the 6-siloxy substituent are also studied under these reaction conditions.Catalytic hydrogenolysis either gives the acyclic amine 16 or it stops at the stage of the proline derivative 21.Mechanistic features of these synthetically valuable transfomations are discussed.