2- Oxetanone

DimeriZa.tlon. A special case of the [2 + 2] cyclo additions is the dimerization of ketenes. Of the six possible isomeric stmctures, only the 1,3-cyclobutanediones and the 2-oxetanones (P-lactones) are usually formed. Ketene itself gives predominandy (80—90%) the lactone dimer, 4-methylene-2-oxetanone (3), called diketene [674-82-8], approximately 5% is converted to the symmetrical dimer, 1,3-cyclobutanedione [15506-53-3] (4) which undergoes enol-acetylation to so-called triketene [38425-52-4] (5) (44). 

Very Htde is known about the toxicology of other dimeric ketenes. For the dimeric dimethylketene there is equivocal evidence of tumors resulting from massive exposure in rats reported for the P-lactone form (3,3-dimethyl-4-isopropyhdene-2-oxetanone), whereas the symmetric form (2,2,4,4 tetramethylcyclobutane-l,3-dione) induces tumors in mice after lengthy skin appHcations. 

Oxetanone, 3,3,4,4-tetramethyl-solvolysis, 7, 380 2-Oxetanone, 4-trichloromethyl-decarboxylation, 6, 374 dehydrochlorination, 7, 374 structure, 6, 366 2-Oxetanone, 3-trimethylsilyl-synthesis, 7, 395... 

Chemical Designations - Synonyms Betaprone Hydracrylic acid, beta-lactone 2-Oxetanone Propanolide beta-Propionolactone Chemical Formula OCH2CH2CO. 

Methods for the synthesis of optically active (3-lactones (2-oxetanones) 99T6403. 

Michael addition of the enolate of (42 )-4-rm-butyl-3-methyl-2-oxetanone to dimethyl (Z)-butenedioate yields a single diastereomer. This provides a method to control two new vicinal stereogenic centers one quaternary and one tertiary. The topicity of the addition is u with respect to the 3,3 -bond and l with respect to the 3, 4 -bondI09. 

C22H40O3 111466-59-2) see Orlistat (35,45)-3-hexyl-4 [(27f)-2-hydroxytridecyl]-2-oxetanone (C22H42O3 104872-06-2) see Orlistat n-hexyl isocyanate... 

The method outlined here competes well with the method developed earlier by Danheiser, et al.618 Its superiority is based on the fact that phenyl ester enolates give almost the same results as the S-phenyl thiolester enolates. However, handling the malodorous benzenethiol for the preparation of the active acid derivative and during workup of the p-lactone can be avoided. In addition, phenol is much cheaper than benzenethiol. The method is well suited for the preparation of p-lactones from symmetrical and unsymmetrical ketones. In addition to 3,3-dimethyM-oxaspiro[3.5]nonan-2-one, ( )-3-ethyl-1-oxaspiro[3.5]nonan-2-one and (3R, 4R )- and (3R, 4S )-4-isopropyl-4-methyl-3-octyl-2-oxetanone were prepared by this procedure in high yields (Notes 11 and 12). In the case of unsymmetrical ketones the less sterically crowded diasteroisomer is formed preferentially. With aldehydes as the carbonyl component the yields are unsatisfactory, because of the competitive formation of 1,3-dioxan-4-ones.6... 

The cycloaddition of aldehydes and ketones with ketene under the influence of quinine or quinidine produce chiral 2-oxetanones [46,47]. Solvolytic cleavage of the oxetanone, derived from chloral, and further solvolysis of the trichloromethyl group leads to (5)- and (R)-malic acids with a 98% ee [46] (the chirality of the product depends on the configuration of the catalyst at C-8 and, unlike other alkaloid-induced reactions, it is apparently independent of the presence of the hydroxyl group). No attempts have been made to catalyse the reaction with chiral ammonium salts. 

Synonyms AI3-24257 AIDS-6024 Betaprone BPL BRN 0001360 Caswell No. 709 CCRIS 536 EINECS 200-340-1 EPA pesticide chemical code 010901 Hydracrylic acid p iactone 3-Hydroxypropionic acid lactone p Lactone NSC 21626 Oxetan-2-one 2-Oxetanone Propano-lide Propiolactone 1,3-Propiolactone 3-Propiolactone p Propionolactone 3-Propionolactone p Propro-lactone UN 2810. 

Oxetanone, see p-Propiolactone Oxidation base 10, see p-Phenylenediamine Oxidation base 10a, see p-Phenylenediamine Oxiranemethanol, see Glycidol Oxiranylmethanol, see Glycidol... 

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