Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1996-04-16
1997-09-23
Owens, Amelia
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
549271, 549272, 549273, 549292, 549295, 549322, 549323, 549324, C07D31300, C07D30702
Patent
active
056706618
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a process for producing lactones, particularly starting from cyclic lactones. The invention also relates to the lactones obtained with the process.
A process for oxidizing ketones, including cyclic ketones, by using permonosulfuric acid as oxidizing agent has been known since the last century as the Baeyer-Villiger reaction (A. Yon Baeyer and V. Villiger, Ber. 1899, 32, 3265; 1400, 33, 850). Other oxidizing agents have been used for this reaction, such as for example peracetic acid, described by R. Criegel (Liebig Annalen, 1948, 560, 127) and in British patent No. 1,203,752. In particular, peracetic acid entails problems, first of all due to the unavoidable co-production of acetic acid, which must in any case be isolated by separation from a high-boiling and thermally unstable product such as a lactone. Furthermore, peracetic acid is rather unstable and tends to decompose, thus creating problems in safety and reaction control. Finally, selectivity is unpredictable and generally rather low, in some cases around 25%.
The use of peracid salts such as magnesium permonophthalate (described in Syntesis 1015-1017, 1987) is also known; however, this salt requires an aqueous environment that entails a high level of lactone hydrolysis or persalts such as sodium perborate, described in U.S. Pat. No. 4,988,825, which requires a troublesome separation and recycling of boric acid.
The oxidizing agent most widely used is metachloroperbenzoic acid, described in Syntetic Comm 19, 829-833, 1989. In particular, metachloroperbenzoic acid requires rather diluted solutions, since otherwise it does not dissolve, and this entails larger reactor volumes and a very slow kinetics. Furthermore, subsequent purification is very onerous, since the solubilities of metachlorobenzoic acid, of metachloroperbenzoic acid and of the reaction products are rather similar, and therefore many successive crystallizations are required. The selectivity of the reaction is not very high anyway. Furthermore, metachloroperbenzoic acid requires an equimolar amount of trifluoroacetic acid (TFA), which is a highly expensive product with separation problems that are worsened by the poor thermal stability of TFA and of the reaction products; metachloroperbenzoic acid is scarcely reactive, indeed inert with certain ketone substrates and is industrially available with a 70% titer in a relatively impure form for chlorination by-products.
Finally, synthesis of lactones starting from cyclic ketones entails unpredictable regioselectivity and chemoselectivity.
EP-A-0 548 774 discloses a process for producing a lacton or an ester by the oxidation of ketones with oxygen in the presence of an aldehyde either in the absence of catalyst or in the presence of a heterogeneous iron-containing or ruthenium-containing catalyst. However the process cannot be said to be advantageous from the industrial point of view, because the used aldehyde is in very high amounts and is converted to the corresponding carboxylic acid which can be considered as a by-product.
JP-A-5 230 048 discloses a process for producing a lacton with 4-5 complicated passages, starting from raw material different from those of the field of the present invention.
EP-A-0 332 802 discloses only the use of an unsubstituted lacton, but does not disclose anything about its preparation.
JP-A-4 001 189 discloses the preparation of large-ring lactons for manufacturing of drugs, and useful high grade perfume, by oxidising large ring ketons in the presence of acqueous H.sub.2 O.sub.2 and reciclable strong acidic cation exchange resins. However this process involves the use of high amount of resin which can also give rise to problems for its stability.
GB-A-1 219 332 discloses a process for the preparation of substituted gamma-butirrolactons, by acylation of an olefinic compound with manganese oxide. A large amount of manganese oxide must be used, with the co-production of many by-products, and with a very difficult separation.
U.S. Pat. No. 3 380 457 discloses a process for the preparat
REFERENCES:
patent: 3380457 (1968-04-01), Schumacher
patent: 4988825 (1991-01-01), Bove
Patent Abstracts of Japan, 17:689, Abstract no. C-1143, 1993.
WPI Database, Week 9207, Derwent Publications Ltd., AN 92-053946 (1992).
Bianchini Roberto
Cotarca Livius
Industrie Chimiche Caffaro S.P.A.
Owens Amelia
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