4- oxazolidine-2,5-dione

Oxazolidine-4,5-dione, At-benzoyl-synthesis, 6, 231 Oxazolidinediones reactions, 6, 214 structure, 6, 179 Oxazolidine-2,4-diones as anticonvulsants, 1, 166 NMI 6, 181 reactions, 6, 214 s mthesis, 6, 231 OxazoIidine-2,5-diones crystal structure, 6, 185 reactions, 6, 214 polymers, 1, 307 s mthesis, 6, 231 Oxazolidine-4,5-diones synthesis, 6, 231 Oxazolidines... 

The residue is dissolved in ether and the solution is washed with sodium chloride solution and then with a little sodium thiosulfate solution. The ethereal solution is dried over sodium sulfate and ether removed by distillation. A yield of 108 parts of 3,5,5-trimethyl-oxazolidine-2,4-dione is obtained having a melting point of 45° to 46°C with slight softening at 43°C. This represents a 75% theory yield on the ethyl o-hydroxy-iso-butyrate taken. The product may be further purified by dissolving the minimum quantity of dry ether and cooling to -10°C. The product so obtained melts sharply at 45.5° to 46.5°C, according to U.S. Patent 2,559,011. 

Heterocycles like l,4,2-dioxazole-5-ones and 3-hydroxy-l,3-oxazolidine-2,4-diones are formed from a 2-hydroxycarbohydroxamic acid and CDI in the following reactions [117]... 

Chemical Name (/LS )-3-(3,5-dichlorophcnyl)-5-vinyl-l,3-oxazolidine-2,4-dione 3-(3,5-dichlorophenyl)-5-ethenyl-5-methyl-2,4-oxazolidinedione CAS Registry No 50471-44-8... 

Irradiation of a benzene solution of 5-phenyl Af-benzoylformyl-A-p-tolylthiocar-bamate 48a (Scheme 23) gave 5-phenyl-5-phenylthio-3-p-tolyloxazolidine-2,4-dione 49a in 61% yield accompanied by oxazolidine-2,4-dione dimer (15%), p-tolyl isocyanate (22%), and diphenyl disulfide [29]. Photolysis of 48a in the solid state gave oxazolidine-2,4-dione 49a in 96% yield. For the N-methyl derivative, 48b, compared to the solution photochemistry in which only 8% of oxazolidinedi-one 49b was obtained with a complex mixture, radical cyclization proceeds selectively to give oxazolidinedione in 75% yield in the solid state. Whereas N-p-tolyl and A-methyl derivatives, 48a and 48b, formed achiral crystals, the N-benzyl derivative 48c crystallized in chiral space group P2. Photolysis of the chiral... 

SYNS AC 1198 BAX 1400Z DIMETHADIONE DIMETHYLOXAZOLIDINEDIONE 5,5-DIMETHYL-OXAZOLIDINE-2,4-DIONE 5,5-DIMETHYL-2,4-OXAZOLIDINEDIONE DMO EUPRACTONE NSC-30152... 

Finally, in section, it is noted that the hydroxyamide (4.24) cyclizes on addition of phosgene to give the fungicide 1,3-oxazolidine-2,4-dione, "Vinclozolin", (4.25) [1841a] ... 

The interatomic distance between the reacting carbonyl carbon and the other carbonyl oxygen for generating oxazolidine-2,4-dione is 3.37 A, and the distance between the carbonyl carbon and the sulfur atoms is 4.72 A. Furthermore, for the hydrogen abstraction of the A -benzyl derivative, the distance between the carbonyl oxygen and hydrogen atoms is 4.45 A, which is much larger than the sum of the van der Waals radii (2.9 A). This reaction provides an example of an... 

A -Acyl-oxazolidin-2-ones, as 203, are widely used in aldol reactions, however an unprecedented use of the aldol adducts for a stereoselective synthesis of trisubstituted a, 3-unsaturated amides and acids was reported. The yy -aldol adduct 204 underwent clean elimination upon treatment with KHMDS and afforded the E -olefin 205 with a 97% ds. The reaction was wide in scope but with a loss in selectivity using a,P-unsaturated or chiral aldehydes <05OBC2976>. This synthetic approach found immediate application in the synthesis of semiplenamide C 206 <05TL5547>. Oxazolidin-2,4-diones 207, obtained from cyanohydrins, can be easily converted into the corresponding a-hydroxyamides 208 in a reaction that can be accelerated by microwaves <05T7247>. 

The ring contraction of barbiturates is observed in the course of hydrolytic degradation (Section III,D). N-Substituted barbiturates 151 (R1 = R2 = alkyl, R3 = H) yield the 5-substituted oxazolidine-2,4-dione 152, and N,N-unsymmetrically substituted barbiturates yield a mixture of both 152 and 153. 5-Bromobarbituric acid and its derivatives give a mixture of iminooxazolidin-4-one and hydantoin.409... 

Dichlozoline (35), 3-(3,5-dichlorophenyl)-5,5-dimethyl-l, 3-oxazolidine-2,4-dione, is a white, crystalline compound, stable to heat and almost insoluble in water (2.5 mg/kg at 25°C). Its acute oral LD50 for rats is higher than 10 000 mg/kg. In 90-day feeding tests a daily diet of 70 mg/kg produced no pathological changes in mice and rats (Iwami et al., 1969 and 1974). The active substance is rapidly metabolised in rats and excreted. The metabolites are hydroxylated at position 4 of the benzene ring, and the oxazoline can also be modified (Sumida et al., 1973). Dichlozoline is not toxic to fish, bees or earthworms. 

Reduction of 68 with lithium aluminum hydride occurs at the C=N linkage to give the corresponding oxazolidones.165 Alkaline hydrolysis of 68 produces the starting hydroxy ketones.165 The enol ether (60) undergoes O -"iV-alkyl migration on heating to 180° to afford the oxazolidine-2,4-dione. This observation probably accounts for the discrepancy in results mentioned earlier.158,159... 

Further examples using rapidly equilibrating screwed/helical/spiral molecules that happen to crystallize in chiral space groups have been provided by Sakamoto. [11c] These are photochemical formations of chiral oxetanes, / -lactames, oxazolidine-2,4-diones, aziridines, oxazolines, phthalides, and -thio-lactames. [11c] In most cases the ee values had to be improved by going to -78 °C or to low conversion . Whereas the latter technique is frequently preferred it is often dubious for the normal selective irradiations (only the educt absorbing the light), if the crystal reacts from its surface down into the bulk, multilayer by multilayer as these become transparent at very advanced local conversions. [14, 15] Thus, no basis exists for assumptions that the optical yield may increase to quantitative values at very low conversions, while the error limits will not allow to secure such claims. Nevertheless, there is the risk that... 

The ureide function present in oxazolidine-2,4-dione depicts a close resemblance to hydantoin, differing only in the replacement of NH moiety in the latter by an oxygen atom at Cj. 

Cyclization of dimethyl ( S)-malate (2) with methyl or ethyl isocyanate affords oxazolidin-2,4-diones (174) in 60 or 62% yield, respectively. This heterocyclic system provides the basic... 

The enantioselective synthesis of monoprotected fra 5-2,5-pyrrolidine dialcohol 1119, a potentially useful intermediate for the construction of pyrrolizidine alkaloids, uses ( S)-malic acid as the chiral source and radical cyclization to fabricate the heterocycle (Scheme 164) [236]. The crucial intermediate 1112 is prepared from acetonide 454b by a Mitsunobu reaction of 1110 with oxazolidine-2,4-dione, resulting in inversion of configuration at the hydroxyl-bearing carbon. Reduction of the 4-carbonyl group of heterocycle 1111 with sodium borohydride followed by dehydration of the resulting alcohol furnishes 1112. 

The same group prepared N-(/S-D-glucopyranosyl)oxazolidine-2,4-diones [146] and N-(/l-D-glucopyranosyl)imidazolidine-2,4-diones [147] by desulfurization-condensation of glucosyl isothiocyanate with a-hydroxyacids and J -substituted a-aminoacids, respectively, in the presence of silver triflu-oroacetate and triethylamine. 4-Glucosyl-l,2,4-oxadiazolidine-5-thiones were also prepared by reaction of protected glucosyl isothiocyanates with an ox-aziridine ring [148]. 

The Leuchs substances, NCA-s, oxazolidine-2,4-diones, can also be synthesized by the method of Fuchs (1910) from amino acids and phosgene, a method further developed by Farthing (1950). According to Curtius, NCA s can be generated from malonic acid half azides as well, through a-isocyanatocarbonic acids (Curtius degradation. Fig. 4). 

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