Pantoyl lactone

The most effective agents for diphosphate formation were NHj)HCOO, H2O2 and SCN-. The formation of the cyclic triphosphate was favoured by maleic anhydride or pantoyl lactone, with Ca2+ being added in both cases. [Pg.120]

The hydrogenation of ketones with O or N functions in the a- or / -position is accomplished by several rhodium compounds [46 a, b, e, g, i, j, m, 56], Many of these examples have been applied in the synthesis of biologically active chiral products [59]. One of the first examples was the asymmetric synthesis of pantothenic acid, a member of the B complex vitamins and an important constituent of coenzyme A. Ojima et al. first described this synthesis in 1978, the most significant step being the enantioselective reduction of a cyclic a-keto ester, dihydro-4,4-dimethyl-2,3-furandione, to D-(-)-pantoyl lactone. A rhodium complex derived from [RhCl(COD)]2 and the chiral pyrrolidino diphosphine, (2S,4S)-N-tert-butoxy-carbonyl-4-diphenylphosphino-2-diphenylphosphinomethyl-pyrrolidine ((S, S) -... [Pg.23]

BINAP, 127, 171, 191, 194, 196 olefin reaction, 126, 167, 169, 191 organic halides, 191 Pancreatic lipase inhibitors, 357 Pantoyl lactone, 56, 59 para-hydrogen, 53 Peptides, matrix structure, 350 Perhydrotriphenylene, crystal lattice, 347 Pericyclic reactions, 212 chiral metal complexes, 212 Claisen rearrangement, 222 Diels-Alder, 212, 291 ene reaction, 222, 291 olefin dihydroxylation, 150 Phase-transfer reactions asymmetric catalysis, 333... [Pg.196]

Ketopantolactone was reduced with diphenylsilane in the presence of the Rh/4 complex in THF at 0 °C followed by desilylation with an acidic methanol affording (S)-pantoyl lactone in 84% optical yield (Scheme 4) [17]. (S)-Ethyl 4-hydrox-ypentanoate was obtained in 80% ee by the reduction of ethyl 4-oxopentanoate with the Rh/4 complex in toluene followed by cleavage of the silyl ether with a neutral methanol [17]. [Pg.59]

Molar yield of pantoyl lactone (%) Molar yield of pantoic acid (%) Molar yield of ethyl pantothenate (%)... [Pg.66]

ASYMCTRIC HYDROGENATION OF KETOPANTOYL LACTONE D-(-)-PANTOYL LACTONE... [Pg.18]

The submitter claims that tetrahydrofuran can also be used giving D-(-)-pantoyl lactone with 83.3-84,8% ee. This was not checked. [Pg.20]

Ketopantoyl lactone has also been reported to be easily prepared by the oxidation of d,l-pantoyl lactone with alkaline metal hypochlorite5 or by reaction of sodium dimethylpyruvate with formaldehyde in the presence of potassium carbonate.5... [Pg.21]

D-(-)-Pantoyl lactone 1s a key intermediate for the synthesis of pantothenic acid which is a member of the vitamin B-complex and is an important constituent of Coenzyme A. Although D-(-)-pantoyl lactone has been obtained by classical optical resolution using quinine, ephedrine, and other chiral amines, catalytic asymmetric synthesis appears to be more effective... [Pg.23]

D-(-)-pantoyl lactone with 95-100% ee. However, the isolation procedure from aqueous media in these microbial reductions, i.e., extraction, recovery of raw materials, and purification, is very troublesome because of the high solubility of the product in water. Consequently, the present method has considerable advantages from a synthetic point of view, e.g., (i) the yield of the reaction is virtually 100%, and (n) isolation of the product is simple and convenient since the reaction is carried out in small amounts of nonaqueous media. [Pg.23]

Ketopantoyl lactone 2,3-Furandione, dihydro-4,4-dimethyl (8,9) (13031-04-4) D-(-)-Pantoyl lactone 2(3H)-Furanone, dihydro-3-hydroxy-4,4-dimethyl -,... [Pg.25]

I. Ojima, T. Kogure, and Y. Yoda 18 ASYMMETRIC HYDROGENATION OF KETOPANTOYL LACTONE D-(-)-PANTOYL LACTONE... [Pg.292]

Asymmetric reduction of prochiral carbonyl compounds for the production of chiral alcohols D-pantoyl lactone production by... [Pg.355]

ASYMMETRIC REDUCTION OF PROCHIRAL CARBONYL COMPOUNDS FOR THE PRODUCTION OF CHIRAL ALCOHOLS D-PANTOYL LACTONE PRODUCTION BY ASYMMETRIC REDUCTION... [Pg.356]

The development of a novel production system for D-pantoyl lactone (which is a lactone compound carrying a chiral hydroxy group and a chiral intermediate for the commercial production of D-pantothenate) by microbial asymmetric reduction has been undertaken. D-pantothenate is mainly used in various pharmaceutical products and as an animal feed additive, the current world production of calcium pantothenate being about 6,000 tons per year. Conventional commercial production of D-pantoyl lactone has depended exclusively on chemical synthesis involving optical resolution of a chemically synthesized racemic pantoyl lactone, which is the most troublesome step of the pantothenate synthesis process. [Pg.357]

DISCOVERY OF NOVEL LACTONASES PROMISING FOR ENZYMATIC RESOLUTION OF RACEMIC PANTOYL LACTONE... [Pg.357]

Figure 19.1. Diversity of microbial reduction of ketopantoyl lactone (a) and COBE (b). A, yeasts O, molds , bacteria , actinomycetes , basidiomycetes PL, pantoyl lactone KPL, ketopantoyl lactone.

Pantoyl lactone H2O D-Pantoic acid L-Pantoyl lactone... [Pg.358]

D-pantoyl lactone (Fig. 19.2). This type of hydrolysis reaction is catalyzed by many filamentous fungi such as Fusarium oxysporum. Since the reaction seemed to be a promising one for the enzymatic resolution of racemic pantoyl lactone, the enzyme responsible for this hydrolysis was characterized in some detail. [Pg.358]

Inhibitors chelating reagents, L-pantoyl lactone, Mn2 Zn2+, Fe2+, Cu2+ chelating reagents, Fe2+, Pb2 Sn2 Al3 Fe3+ diisopropylphosphofluoridate, phenylmethanesulfonyl fluoride, Ilg2, Fe3+... [Pg.359]

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