3-Methyl-2-oxazolidinone

PC propylene carbonate NMO 3-methyl-2-oxazolidinone TBAI tetrabutylammonium iodide AN acetonitrile PN propionitrile GN glutaronitrile MAN methoxyacetonitrile MPN 3-methoxypropionitrile TBP tert-butylpyridine HMIml l-hexyl-3-methylimidazolium iodide DMPIml 1,2- dimethyl-3-propy-limidazolium iodide SOC Sumitomo Osaka Cement Co. Ltd. 

Methyl-2-oxazolidinone A-methyl-2-pyrrolidinone 3-Methyl sydnone Pyridine... 

Table 4 Performances of solid-state dye-sensitized solar cell, T102/N3/Carrageenan solid containing aceonitrile/3-methyl-2-oxazolidinone (1/1) and (C3H7)4Nl/l2(0.3 M/0.03 M) /Transparent Pt under 98 mW cm irradiation from a 500 W xenon lamp (reprinted with permission from Chemical Society of Japan [56])...

Methyl-2-oxazolidinone (NMO) is isostructural with EC with an N-CH3 group substituted for one of the EC ring oxygen atoms. It is a highly polar solvent (er=78 at 25 °C) and was once used in primary lithium cells [54]. However, its oxidation potential on a glassy carbon is much lower than that of PC [55]. To increase its... 

Nanbu, N. Hagiyama, K. Takehara, M. Ue, M. Sasaki, Y., Physical and electrolytic properties of difluorinated 3-methyl-2-oxazolidinones and their application to lithium rechargeable batteries. Electrochemistry 2010, 78,450-453. 

The mechanism of the stereoselective syntheses of (K)-3-aryl-5-(hydroxy-methyl)oxazolidinones via the Mannenin reaction of aryl carbamic acid esters with (Jt)-glycidyl butyrate has been explored in detail by Brickner et al. [60]. Namely, N-lithiated carbamate derivatives of anilines are allowed to react with the commercially available (K)-glycidyl butyrate (96-98% enantiomeric excess ee) under appropriate conditions to obtain enantiomerically pure (Jt)-3-aryl-5-(hydroxymethyl)oxazolidinones in 85-99% yields, according the pathways depicted in Scheme 19. 

Interestingly, the catalytic reaction yielded predominantly the threo-4-(chloro-methyl)oxazolidinones, whereas under thermal conditions in 1,1,2,2-tetrachlo-roethane (TCE) the eryth.ro isomer was formed exclusively. If the reaction proceeded via aziridine formation followed by nucleophilic ring opening, the product stereochemistry would be erythro. As this was not the case, the involvement of an N-centered radical species was suggested (Figure 3.8). 

Vinyl methyl benzimidazole Vinyl methyl dichlorosilane Vinyl methyl oxazolidinone Vinyl oxyethylurea Vinyl propionate Vinylpyridine Vinyl siloxane Vinylsuccinimide Vinyl stearate... 

The desilylacetylated qrcloadducts, produced from the reactions of trimethylsilyl-diazomethane with 3-crotonoyl-2-oxazolidinone or 3-crotonoyl-4,4-dimethyl-2-oxa-zolidinone, were transformed to methyl traws-l-acetyl-4-methyl-l-pyrazoline-5-car-boxylate through the reactions with dimethoxymagnesium at -20 °C. When the optical rotations and chiral HPLC data were compared between these two esters, it was found that these two products had opposite absolute stereochemistry (Scheme 7.39). The absolute configuration was identified on the basis of the X-ray-determined structure of the major diastereomer of cycloadduct derived from the reaction of trimethylsilyldiazomethane to (S)-3-crotonoyl-4-methyl-2-oxazolidi-none. 

Chemical Name 5-[(o-Methoxyphenoxy)methyl]-2-oxazolidinone Common Name Methoxadone... 

Chemical Name 5-[(methylthio)methyl] -3-[ [(5-nitro-2-furanyl)methylene] amino] -2-oxazolidinone... 

A yellow crystalline precipitate was immediately formed, which, after crystallization from acetic acid, melted at 182°C and consisted of N-(5-nitro-2-furfurylidene)-3-amino-5-methyl-mercaptomethyl-2-oxazolidinone. 

The synthesis of the E-ring intermediate 20 commences with the methyl ester of enantiomerically pure L-serine hydrochloride (22) (see Scheme 9). The primary amino group of 22 can be alkylated in a straightforward manner by treatment with acetaldehyde, followed by reduction of the intermediate imine with sodium borohydride (see 22 —> 51). The primary hydroxyl and secondary amino groups in 51 are affixed to adjacent carbon atoms. By virtue of this close spatial relationship, it seemed reasonable to expect that the simultaneous protection of these two functions in the form of an oxazolidi-none ring could be achieved. Indeed, treatment of 51 with l,l -car-bonyldiimidazole in refluxing acetonitrile, followed by partial reduction of the methoxycarbonyl function with one equivalent of Dibal-H provides oxazolidinone aldehyde 52. 

Reaction of the optically active /V-unsubstituted 5-methyl-2-oxazolidinone 12 (and its enantiomer), however, does not proceed with complete trans selectivity118. 

Once again, excellent selectivity for formation of the j3-methyl isomer is observed in the case of the Lewis acid catalyzed reaction of the boron enolate of (4S )-4-isopropyl-3-(l-oxopropyl)-2-oxazolidinone 4177 (see Appendix). 

An enantiopure bicyclic triazolium salt was prepared by a three step conversion of the oxazolidinone 31 (Scheme 18). The first step was a methylation affording an iminoether which was transformed into the phenylhydrazone 32. A final cyclization gave the salt 33 as a cristalline solid [25]. 

The cycloberbine 339 derived from coptisine (65) was reduced with lithium aluminum tri-tert-butoxyhydride to afford the trans-alcohol 340 along with a small amount of the cis-alcohol (Scheme 62). Treatment of 340 with ethyl chloroformate effected C-8—N bond cleavage and simultaneous oxyfunc-tionalization at C-8 with the desired stereochemistry to produce the oxazolidinone 341. This was hydrolyzed with potassium hydroxide and then underwent N-methylation to give ( )-ochrobirine (343). Similarly, the ochrobirine analog 344 was also obtained from berberine (15) (171). 

When heated above 200 °C, pure 5-methyl-2-oxazolidinone decomposes into two products, C02 gas and N-(2-hydroxypropyl) imidaz-olidinone. The reaction stoichiometry is ... 

Solution-phase enantioselective synthesis of 437 and 438 thus achieved was also translated into solid-phase synthesis <2002TL8981>. The oxazolidinone 441 prepared from L-tyrosine methyl ester via 440 was attached to Merrifield resin to produce 442. Resin-bound 442 was converted to 443 (Scheme 98). 

Annual Volume 71 contains 30 checked and edited experimental procedures that illustrate important new synthetic methods or describe the preparation of particularly useful chemicals. This compilation begins with procedures exemplifying three important methods for preparing enantiomerically pure substances by asymmetric catalysis. The preparation of (R)-(-)-METHYL 3-HYDROXYBUTANOATE details the convenient preparation of a BINAP-ruthenium catalyst that is broadly useful for the asymmetric reduction of p-ketoesters. Catalysis of the carbonyl ene reaction by a chiral Lewis acid, in this case a binapthol-derived titanium catalyst, is illustrated in the preparation of METHYL (2R)-2-HYDROXY-4-PHENYL-4-PENTENOATE. The enantiomerically pure diamines, (1 R,2R)-(+)- AND (1S,2S)-(-)-1,2-DIPHENYL-1,2-ETHYLENEDIAMINE, are useful for a variety of asymmetric transformations hydrogenations, Michael additions, osmylations, epoxidations, allylations, aldol condensations and Diels-Alder reactions. Promotion of the Diels-Alder reaction with a diaminoalane derived from the (S,S)-diamine is demonstrated in the synthesis of (1S,endo)-3-(BICYCLO[2.2.1]HEPT-5-EN-2-YLCARBONYL)-2-OXAZOLIDINONE. 

Reaction of isatin or thioisatin 263 with (R)-(—)-thiaproline afforded thiazolo-oxazolidinones 264 as precursor of azomethine ylides, obtained by decarboxylation, for 1,3-dipolar cycloadditions (Equation 116) <2002SC435, 2004PS2549>. Condensation of 5-(alkylamino)methyl-2-pyrazolines 265 with ketones or aldehydes led to tetrahy-dro-imidazo[l,5-7]pyrazoles 266 (Equation 117) <1998JCCS375>. 

Asymmetric Diels-Alder reactions. Unlike methyl crotonate, which is a weak dienophile, chiral (E)-crotonyl oxazolidinones when activated by a dialkylaluminum chloride (1 equiv.) are highly reactive and diastereoselective dienophiles. For this purpose, the unsaturated imides formed from oxazolidinones (Xp) derived from (S)-phenylalanol show consistently higher diastereoselectivity than those derived from (S)-valinol or (IS, 2R)-norephedrine. The effect of the phenyl group is attributed in part at least to an electronic interaction of the aromatic ring. The reactions of the unsaturated imide 1 shown in equation (I) are typical of reactions of unsaturated N-acyloxazolidinones with cyclic and acyclic dienes. All the Diels-Alder reactions show almost complete endo-selectivity and high diastereoselectivity. Oxazolidinones are useful chiral auxiliaries for intramolecular Diels-Alder... 

Allenamides are more stable and hence easier to handle in synthetic manipulations [152], When allenamide 187 was heated with 2equiv. of acrolein or methyl vinyl ketone (MVK), cycloadducts were isolated as single regioisomers. Allenamides containing either an oxazolidinone or imidazolidinone moiety also reacted with these a,/1-unsaturated carbonyl compounds under thermal conditions. 

FIGURE 8.17 Preparation of Fmoc-A-methylamino acids by methylation of Fmoc-amino acids.90 Acid-catalyzed reaction of substrate with formaldehyde at elevated temperature with removal of water by azeotropic distillation produces the oxazolidinone, which is then opened and reduced to the A-methylated derivative. 

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