Topic
Morpholine
About: Morpholine is a research topic. Over the lifetime, 5411 publications have been published within this topic receiving 51063 citations. The topic is also known as: diethylene imidoxide & diethylene oximide.
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TL;DR: Mechanistic studies revealed that these complexes are rapidly reduced to the active NHC-Pd(0) species at ambient temperature in the presence of KOtBu, thus avoiding the formation of deleterious off-cycle Pd(II)-thiolate resting states.
Abstract: A series of new, easily activated NHC-Pd(II) precatalysts featuring a trans-oriented morpholine ligand were prepared and evaluated for activity in carbon-sulfur cross-coupling chemistry. [(IPent)PdCl2(morpholine)] (IPent=1,3-bis(2,6-di(3-pentyl)phenyl)imidazol-2-ylidene) was identified as the most active precatalyst and was shown to effectively couple a wide variety of deactivated aryl halides with both aryl and alkyl thiols at or near ambient temperature, without the need for additives, external activators, or pre-activation steps. Mechanistic studies revealed that, in contrast to other common NHC-Pd(II) precatalysts, these complexes are rapidly reduced to the active NHC-Pd(0) species at ambient temperature in the presence of KOtBu, thus avoiding the formation of deleterious off-cycle Pd(II)-thiolate resting states.
60 citations
TL;DR: In this article, the relative configuration of the two diastereoisomers of (±)2-[∢-(2-ethoxyphenoxy)benzyl] morpholine is determined by a synthesis involving regio and stereo specific reactions.
60 citations
TL;DR: A new family of N-form immonium-type coupling reagents that differ in their carbocation skeleton structure is described, and the fluoroamidinium salt performed extremely well in the presence of only 1 equiv of base, thereby confirming the effect of the proton acceptor in the reaction.
Abstract: Here we describe a new family of N-form immonium-type coupling reagents that differ in their carbocation skeleton structure. The N-methylpiperazine derivative failed to form immonium salts, while the thiomorpholine derivative did not give better results than the coupling reagents currently used. The presence of the morpholine had a marked influence on the solubility and stability as well as the reactivity of the reagent. Finally, the fluoroamidinium salt performed extremely well in the presence of only 1 equiv of base, thereby confirming the effect of the proton acceptor in the reaction.
60 citations
TL;DR: The chemical structures of the newly synthesized compound ware characterized by IR, 1H-N MR, 13C-NMR and mass spectral analysis and exhibited promising activities.
Abstract: 6-[(4-Methoxy/4,9-dimethoxy)-7-methylfurochromen-5-ylideneamino]-2-thioxo-2,3-dihydropyrimidin-4-ones 1a,b were prepared by reaction of 6-amino-2-thiouracil with visnagen or khellin, respectively. Reaction of 1a,b with methyl iodide afforded furochromenylideneaminomethylsulfanylpyrimidin-4-ones 2a,b. Compounds 2a,b were reacted with secondary aliphatic amines to give the corresponding furochromen-ylideneamino-2-substituted pyrimidin-4-ones 3a-d. Reaction of 3a-d with phosphorus oxychloride yielded 6-chlorofurochromenylidenepyrimidinamines 4a-d, which were reacted with secondary amines to afford furochromenylideneamino-2,6-disubstituted pyrimidin-4-ones 5a-d. In addition, reaction of 5a-d with 3-chloropentane-2,4-dione gave 3-chloro-furochromenylpyrimidopyrimidines 6a-d. The latter were reacted with piperazine and morpholine to give 1-(furochromenyl)-pyrimidopyrimidine-3,6,8-triylpiperazines or -3,6,8-triylmorpholines 7a-d. The chemical structures of the newly synthesized compound ware characterized by IR, ¹H-NMR, ¹³C-NMR and mass spectral analysis. These compounds were also screened for their analgesic and anti-inflammatory activities. Some of them, particularly 3-7, exhibited promising activities.
60 citations
TL;DR: In this paper, the 1,2-diarylethylenediamines with tertiary and primary amino groups are formed with no or only moderate diastereoselectivity (products 4a-d(Scheme 2) and 5e-e(scheme 3), respectively); the amine component may contain a strained ring or additional heteroatoms as in azetidin, bis(2-methoxyethyl)amine, piperazine, morpholine, and thiomorpholine (products 6a-e; Table 1).
Abstract: Scope and Limitations of the Reductive Coupling of Aromatic Aldimine Derivatives with Formation of 1,2-Diarylethylenediamine Units, Using Low-Valent Titanium Reagents
Besides the adducts from lithium amides to aromatic aldehydes, iminium salts, animals, and N-silylimines of aromatic aldehydes are coupled by the black suspension obtained from TiCL4 and Mg turnings in tetrahydrofuran (THF). The 1,2-diarylethylenediamines with tertiary and primary amino groups thus obtained are formed with no or only moderate diastereoselectivity (products 4a–d(Scheme 2) and 5–e(Scheme 3), respectively); the amine component may contain a strained ring or additional heteroatoms as in azetidin, bis(2-methoxyethyl)amine, piperazine, morpholine, and thiomorpholine (products 6a–e; Table 1). By an in-situ procedure, ethylenediamines exclusively trans-diaryl-substituted piperazine and perhydro-1,4-diazepine derivatives (products 7a–f; Table 2). Enantiomerically pure monocyclic trans,cis-5-alkyl-2,-3-diaryl-piperazines and diazabicyclo[4.3.0]nonanes and -[4.4.0]decanes are obtained by employing suitable diamines prepared from the amino acids (S)-alanine, (S)-phenylalanine, (S)-proline and from (S,S)- or (R,R)-cyclohexane-1,2-diamine, respectively (products 11a–i, 7e; Table 4). The configuration of all products are derived from the high-field NMR spectra, some of which are discussed in detail (Figs. 1 and 2, Tables 3 and 5); all new compounds are fully characterized by their physical data. Depending upon the structure of the components employed, the yields of purified products range from as low as 7% to essentially quantitative.
60 citations