Results 231 to 240 of about 14,141 (248)

Intramolecular oxyacetoxylation of N-allylamides: an expeditious synthesis of oxazolines and oxazines by using a PhI(OAc)2/hydrogen fluoride-pyridine system.

Organic and biomolecular chemistry, 2016
The synthesis of oxazolines and oxazines from N-allylamides was accomplished via an unprecedented reaction set. This reaction involved an intramolecular cyclization of N-allylamides resulting from nucleophilic attack of the allylamine on the benzoxazin-4-
J. Ranjith, Nomula Rajesh, B. Sridhar, P. Radha Krishna   +3 more
semanticscholar   +1 more source

Stereoselective Chirality Extension of syn,anti- and syn,syn-Oxazine and Stereochemical Analysis of Chiral 1,3-Oxazines: Stereoselective Total Syntheses of (+)-1-Deoxygalactonojirimycin and (-)-1-Deoxygulonojirimycin.

Journal of Organic Chemistry, 2016
This paper describes the stereoselective total syntheses of (+)-1-deoxygalactonojirimycin and (-)-1-deoxygulonojirimycin via new chiral building blocks syn,anti,syn-oxazine 11a and syn,syn,anti-oxazine 13a.
Jin-Seok Kim, Yong-Taek Lee, Kun-Hee Lee, In-Soo Myeong, Jong-Cheol Kang, Changyoung Jung, Seokhwi Park, W. Ham   +7 more
semanticscholar   +1 more source

Green synthesis of 1,3-oxazines by visible light-promoted catalyst-free C–H activation/cyclization of tertiary amines

Environmental Chemistry Letters, 2021
B. Saikia, Mohit L. Deb, P. Baruah
semanticscholar   +1 more source

Six-Membered Cyclic Nitroso Acetals: Synthesis and Studies of the Nitrogen Inversion Process of N-Silyloxy-3,6-dihydro-2H-1,2-oxazines

, 2016
Silyl nitronates undergo rhodium-catalyzed formal [3+3]-cycloaddition with enol diazoacetates to form N-silyloxy-3,6-dihydro-2H-1,2-oxazines. The scope of the reaction and the extent of the major side process were evaluated.
Alexander S. Shved, A. Tabolin, R. Novikov, Y. Nelyubina, V. Timofeev, S. Ioffe   +5 more
semanticscholar   +1 more source

Palladium-catalyzed highly regioselective 6-exo-dig cyclization and alkenylation of ortho-ethynylanilides: the synthesis of polyene-substituted benzo[d][1,3]oxazines.

Chemical Communications, 2015
A Pd-catalyzed highly regioselective 6-exo-dig cyclization/alkenylation reaction of ortho-ethynylanilides has been developed. This tandem cross-coupling protocol represents a simple, efficient, step- and atom-economic approach for the construction of ...
Zhong-Jian Cai, Chao Yang, Shun‐Yi Wang, S. Ji   +3 more
semanticscholar   +1 more source

Rhodium-catalyzed transannulation of N-sulfonyl-1,2,3-triazoles and epoxides: regioselective synthesis of substituted 3,4-dihydro-2H-1,4-oxazines.

Organic Letters, 2014
Rhodium-catalyzed transannulation of 1,2,3-triazoles and ring-opening reactions of epoxides is described. A number of 3,4-dihydro-2H-1,4-oxazines are obtained in moderate yields probably involving generation of α-imino rhodium(II) carbene species.
Xueji Ma, S. Pan, Hangxiang Wang, Wanzhi Chen   +3 more
semanticscholar   +1 more source

Diastereoselective α-C-H functionalization of aliphatic N-heterocycles: an efficient route to ring fused oxazines.

Chemical Communications, 2014
A novel method for direct C-H functionalization of saturated N-heterocycles allowing easy access to synthetically as well as biologically important and structurally diverse ring-fused oxazines is developed.
Sujit Mahato, Surajit Haldar, C. Jana
semanticscholar   +1 more source

One‐pot Two‐Step Cycloaddition Reaction for Convenient Synthesis of Polycyclic Spirooxindole‐fused [1,3]Oxazines

, 2015
The novel spirooxindoline fused [1,3]oxazines were efficiently synthesized from Diels-Alder reaction of N-arylmaleimides with 1,2-dihydro-2-oxospiro[3H-indole-3,2′-[2H,9aH-pyrido[2,1-b][1,3]oxazines], which were generated in situ from three-component ...
Jing Sun, Hui Gong, Chaoguo Yan
semanticscholar   +1 more source

Solid-phase synthesis and analysis of 3,6-dihydro-2H-1,2-oxazines in their stereo- and regioisomer mixtures

, 2014
3,6-Dihydro-2H-1,2-oxazines were synthesised via solid-phase synthesis to afford mixtures of stereo- and regioisomers. The analytical conditions for the analysis of the isomer ratio suitable for checking of reaction conditions of possible stereoselective
Aidan Harrison, M. Melchionna, P. Franco, J. Hlaváč   +3 more
semanticscholar   +1 more source

Metallic Lakes of the oxazines (Gallamin Blue, Gallocyanin and Coelestin Blue) as Nuclear Stain Substitutes for Hematoxylin

Becher's investigations upon the soluble metallic lakes of the oxazines have been re-investigated, extended and results described. Gallamin blue, gallocyanin and coelestin blue in combination with ferric ammonium sulfate gave the best results.
F. Phoescheh, A. S. Arkush
semanticscholar   +1 more source