4-methylmorpholine

LEY - GRIFFITH Oxidation reagent Oxidation ol alcotwls to caitxnyl compounds with a pemjthenate catalyst and N-methylmorpholine - N-oxIde (NMO), In the presence of other functional gmups... 

V-Methylmorpholine [109-02-4] M 101.2, h 116-117 /764mm, d 0.919, n 1.436, pK 7.38. Dried by refluxing with BaO or sodium, then fractionally distd through a helices-packed column. 

Methylmorpholine-4-oxide monohydrate [7529-22-8] M 135.2, m 71-73 . When dried for 2-3h at high vacuum it dehydrates. Add MeOH to the oxide and distil off the solvent under vacuum until the temp is ca 95°. Then add Me2CO at reflux then cool to 20°. The crystals are filtered off washed with Me2CO and dry. The degree of hydration may vary and may be important for the desired reactions, [van Rheenan et al. Tetrahedron Lett 1973 1076 Schneider and Hanze US Pat 2 769 823 see also Sharpless et al. Tetrahedron Lett 2503 / 976.1... 

Similar hydroxylation-oxidations can be carried out using a catalytic amount of osmium tetroxide with A-methylmorpholine oxide-hydrogen peroxide or phenyliodosoacetate." A recent patent describes the use of triethylamine oxide peroxide and osmium tetroxide for the same sequence. Since these reactions are of great importance for the preparation of the di-hydroxyacetone side-chain of corticoids, they will be discussed in a later section. 

N-Methylmorpholine Oxide-Hydrogen Peroxide Oxidation. The preparation of A-methylmorpholine oxide-hydrogen peroxide is described in Reagents for Organic Synthesis by L. Fieser and M. Fieser. 

Methylmorpholine on treatment with cobalt trifluoride at 100 °C for 3 h yields 10 fluorinated morpholines and a small amount of bis(trifluoromethyl)-fluoromethylamine [/9] (equation 19)... 

With dibenzyl phosphates or phosphonates, treatment with refluxing A-methylmorpholine results in monodebenzylation (60-100% yield). 

The 4-nitrobenzyl group, used in the synthesis of phosphorylated serine, is introduced by the phosphoramidite method and can be cleaved with TFMSA/ MTB/m-cresol/l,2-ethanedithiol/TFA, 4 h, 0° to rt. 7V-Methylmorpholine at 80° also cleaves a 4-nitrobenzyl phosphate triester. 

Pivorarenko and Khilya investigated a series of organic bases including tribenzyl amine, sodium methylate, sodium terf-butylate, n-methylmorpholine,... 

In 400 ml of dimethylformamide was dissolved 15.0 g of bleomycinic acid (copper-containing form). To the solution kept at 0°C by cooling were added 1.1 ml of N-methylmorpholine and 10.3 g of 6-chloro-1 -p-chlorobenzenesulfonyloxybenzotriazole (CCBT) as an activating compound. The mixture was stirred for 5 minutes at 0°C, then admixed with 5.3 g of N-[(S)-1 -phenylethyl] -1 3-diaminopropane and further stirred for 1 hour. 

Ley et al. reported oxidation of alcohols catalyzed by an ammonium perruthenate catalyst dissolved in [NEtJBr and [EMIM][PFg] [60]. Oxygen or N-methylmorpholine N-oxide is used as the oxidant and the authors describe easy product recovery by solvent extraction and mention the possibility of reusing the ionic catalyst solution. 

Initiation Mechanism of Persulfate-Amine N-methylmorpholine [46], which involves the formation ... 

Unfortunately, a serious problem with the osmium tetroxide reaction is that Os04 is both very expensive and very toxic. As a result, the reaction is usually carried out using only a small, catalytic amount of OsO, in the presence of a stoichiometric amount of a safe and inexpensive co-oxidant such as A -methylmorpholine N-oxide, abbreviated NMO. The initially formed osmate intermediate reacts rapidly with NMO to yield the product diol plus... 

Scheme 5. Upjohn s catalytic dihydroxylation process with 0s04 and 4-methylmorpholine /V-oxide (NMO).

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