2-Oxazolidinone

A special problem arises in the preparation of secondary amines. These compounds are highly nucleophilic, and alkylation of an amine with alkyl halides cannot be expected to stop at any specifle stage. Secondary amides, however, can be monoalkylated and lydrolyzed or be reduced to secondary amines (p. 11 If.). In the elegant synthesis of phenyl- phrine an intermediate -hydroxy isocyanate (from a hydrazide and nitrous acid) cyclizes to pve an oxazolidinone which is monomethylated. Treatment with strong acid cleaves the cyclic irethan. 

The alkylurea 576 and oxamide 577 are formed by oxidative carbonylation of amines under CO pressure using Pd/C as a catalyst[518]. The urea formation proceeds under atmospheric pressure using PdCh and CuCl2[519]. The mono-and double carbonylations of / -aminoethanol (578 and 579) afford the cyclic carbamate (oxazolidinones) 580 and oxamide (morpholinediones) 581 [520,521]. 

ANTIBACTERIALAGENTSSYNTTiETIC - NITROFURANS] (Vol2) 3-[(5-Nitro-2-furanyl)methyleneamino]-2-oxazolidinone... 

Oxazolidinones. 3-Chloro-4,4-dimethyl-2-oxa2ohdinone [58629-01-9] (10) has been extensively evaluated as a disiafectant (157). It is prepared by phosgenation of (CH2)2CH(NH2)CH20H followed by chlorination ia the presence of caustic. It is a white crystalline soHd with a theoretical av CI2 of... 

C3NO 0 — N — — 2,2 -p-Phenylenebis(5-phenyloxazole) 2-(4-pyridyl)oxazole 2,4-dimethyl-5-(p-nitrophenyl)oxazole 2-oxazolidinone ... 

Propargyl alcohol (332) and (328) react readily with isocyanates in the presence of a basic catalyst to give 4-methylene-2-oxazolidinones (334) and 4-methylene-2-imidazolinones (336), respectively (63JOC991). In the absence of sodium methoxide the intermediate methanes (333) and ureas (335) were obtained and on treatment with sodium methoxide underwent ring closure. Moderate to excellent yields were obtained. 

Oxazolidin-5-one, bis(trifluoromethyl)-reactions, 6, 213 Oxazolidinones polymers, 1, 281-282 reactions, 6, 213 Oxazolidinones, imino-rearrangement, 5, 775 Oxazolidinones, vinyl-polymers, 1, 281 Oxazolidin-2-ones circular dichroism, 6, 185 H NMR, 6, 181 IR spectroscopy, 6, 183 PE spectroscopy, 6, 183 reactions, 6, 213... 

D. s-Aaetyl-2(3B)-oxaaolone. The crude mixture of 3-acety1 4- and 5-chloro-2-oxazolidinone from Step C is placed in a 2-L, three-necked flask equipped with a thermometer, sealed mechanical stirrer, and gas discharge tube. The material is heated to 120°C with stirring, and the temperature is then slowly increased to 150 C and held there until the evolution of gas ceases (Note 10). The cooled, black reaction mixture is distilled at 20 nm. The fractions boiling up to 150°C are collected and redistilled through a 50-cm X 3-cm Vigreux column fitted with a variable take-off head. There is obtained 140-172 g (55-68%) of product, bp 108-112°C (24 mm), which solidifies, rap 35-37°C (Note 11). 

The column was 25 cm long, 4.6 mm I.D. and packed with Partisil 10. It is seen that linear curves were obtained for three different solutes and two different moderators in n-heptane. Scott and Beesley [14] obtained retention data for the two enantiomers, (S) and (R) 4-benzyl-2-oxazolidinone. The column chosen was 25 cm long, 4.6 mm I.D. packed with 5 mm silica particles bonded with the stationary phase Vancomycin (Chirobiotic V provided by Advanced Separations Technology Inc., Whippany, New Jersey). This stationary phase is a macrocyclic glycopeptide Vancomycin that has a molecular weight of 1449.22, and an elemental composition of 54.69% carbon. 

Figure 19 Graph of Corrected Retention Volume of the (S) 4-Benzyl-2-oxazolidinone against the Reciprocal of the Volume Fraction of Ethanol...

Table. 1 Retention Volume of (R) 4-Phenyl-2-oxazolidinone Determined at Different Solvent Compositions...

Figure 20. Calculated Retention Volume of 4-Phenyl-2-oxazolidinone Plotted against Those Experimentally Determined...

Figure 22. A 3-D Set of Curves Relating the Separation Ratio of the Two Enantiomers of 4-Phenyl-2-oxazolidinone to the Composition of a Ternary Solvent Mixture...

The numerical constants were obtained over the temperature range of 5°C to 45°C and a concentration range of 0 to 0.5 volume fraction of ethanol inn-hexane.The effect of temperature and solvent composition on solute retention can, again, be best displayed by the use of 3-D graphs, and curves relating both temperature and solvent composition to the retention volume of the (S) enantiomer of 4-benzyl-2-oxazolidinone are shown in Figure 23. Figure 23 shows that the volume fraction of ethanol in the solvent mixture has the major impact on solute retention. 

The data from the separation of the enantiomers of 4-phenyl-2-oxazolidinone [14] gave an expression for the retention volume of the two enantiomers, which are reiterated as follows. 

Figure 5. Graphs of Retention Time of (R) 4-Benzyl-2-oxazolidinone against Temperature Program Rate for Three Different Initial Temperatures...

Scott and Beesley [2] measured the corrected retention volumes of the enantiomers of 4-benzyl-2-oxazolidinone employing hexane/ethanol mixtures as the mobile phase and correlated the corrected retention volume of each isomer to the reciprocal of the volume fraction of ethanol. The results they obtained at 25°C are shown in Figure 8. It is seen that the correlation is excellent and was equally so for four other temperatures that were examined. From the same experiments carried out at different absolute temperatures (T) and at different volume fractions of ethanol (c), the effect of temperature and mobile composition was identified using the equation for the free energy of distribution and the reciprocal relationship between the solvent composition and retention. 

Pentafluorobenzyl bromide has been used in the derivatization of mercaptans [55] and phenols [36], m the analysis of prostaglandins [37], and in quantitative GC-MS [5S] 1,3 Dichlorotetrafluoroacetone is used for the derivatization of amino acids to the corresponding cyclic oxazolidinones and allows the rapid analysis of all 20 protein ammo acids [d] Pentafluorophenyldialkylchlorosilane derivatives have facilitated the gas chromatographic analysis of a wide range of functionally substituted organic compounds, including steroids, alcohols, phenols, amines, carboxylic acids, and chlorohydrms [4]... 

Phenylaceturic acid cychzes in acetic anhydride to give 2-benzyli-dene-3-acetyl-5-oxazolidinone (70) the previously proposed anhydride structure 71 was shown to be incorrect. Compound 70 reacts... 

For the isoxazolines 284 substituted at position 3, ring-chain tautomerism is depicted by the equilibrium 284 and 285-287 (Scheme 103). In general the cyclic tautomers 284 are strongly preferred. The ring-opened forms exist in equilibrium with 284 in rare cases [95ZOB705 96AHC(66)1, p. 21]. The equilibrium of the oxazolidinones 288 [78MI1, p. 107] is affected by the nature of the solvent. 

Oxazolidinones and dihydrofuranones as inactivators and substrates of monoamine oxidase B, approaches to the design of antiparkinsonian agents 97F343. 

The reaction has wide scope in respect of the dienophUe / -substituent. The representative less reactive dienophiles, crotonoyl- and cinnamoyl-oxazolidinone, react with cyclopentadiene at -15 °C and 25 °C for 20 h and 24 h giving cycloadducts in 99% ee and 96% ee, respectively. The 3-chloropropenoyl derivative also affords the adduct in high optical purity (96% ee) this adduct is transformed to 2-(methoxycar-bonyl)norbornadiene, a useful chiral building block. Thus, the 3-chloropropenoyl derivative can be regarded as a synthetic equivalent of an acetylene dienophile. 

A quinoline-phosphine ligand has been developed by Buono et ah, and its complex 29 with Cu(OTf)2 found to be an effective catalyst for the Diels-Alder reaction between acryloyl-oxazolidinone and cyclopentadiene, affording the cycloadduct... 

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