Porcin. pancreatic lipase

PPL = porcine pancreatic lipase PLE = porcine liver esterase. 

ACOCH2CF3, porcine pancreatic lipase, THF, 60 h, 77% yield. This enzymatic method was used to acetylate selectively the primary hydroxyl group of a variety of carbohydrates. 

ACOCH2CCI3, pyridine, porcine pancreatic lipase, 85% yield.These studies examined the selective acylation of carbohydrates. Mannose is acy-lated at the 6-position in 85% yield in one example. 

Candida cylindracea, phosphate buffer pH 7, Bu20. The 6-0-acetyl of Q -methyl peracetylglucose was selectively removed. Porcine pancreatic lipase will also hydrolyze acetyl groups from carbohydrates. These lipases are not specific for acetate since they hydrolyze other esters as well. In general selectivity is dependent on the ester and the substrate. ... 

Porcine pancreatic lipase, pH 7.5, 23° 4.5 h, 55% yield. These conditions were used to suppress facile racemization of 2-chlorocyclohexenone. ... 

Immobilized PLE was applied to promote stereoselective acetylation of prochiral bis(hydroxymethyl)methyl-phenylgermane 106 (R = Me) with vinyl acetate as a solvent and acyl donor. Later on, the same group reported that each enantiomer of hydridogermane monoacetates 107 (R = H) was obtained either via acetylation of the bis-hydroxy derivative 106 (R = H) or hydrolysis of the corresponding diacetate 108 (R = H). In both methods, porcine pancreatic lipase was used and, obviously, each reaction led to a different enantiomer of 107 (Equation 51). ... 

In 1958 Sarda and Desnuelle [79] discovered the lipase activation at the interfaces. They observed that porcine pancreatic lipase in aqueous solution was activated some 10-fold at hydrophobic interfaces which were created by poorly water-soluble substrates. An artificial interface created in the presence of organic solvent can also increase the activity of the lipase. This interfacial activation was hypothesized to be due to a dehydration of the ester substrate at the interface [80], or enzyme conformational change resulting from the adsorption of the lipase onto a hydrophobic interface [42,81,82]. 

Porcine pancreatic lipase (PPL) catalyzed the polymerization of methyl 6-hy-droxyhexanoate [22]. The polymer with DP up to 100 was synthesized by the polymerization in hexane at 69 °C for more than 50 days. The PPL-catalyzed... 

A variety of enzymes (such as acetylcholine esterase, Porcine pancreatic lipase, Pseudomonas cepacia lipase, and Candida antarcita lipase) have been found useful in the preparation of enantiomerically pure cyclopentenol (+)-2 from 1. The enantiomeric (—)-2 has been prepared from diol 4 by enzymatic acetylation catalyzed by VP-345 with isopropenyl acetate in an organic medium. The key intermediate cyclopentanones (+)-6, (—)-6, 7, and 8, which are useful in the preparation of many bioactive molecules, can be obtained from 3 and 5 via routine chemical transformations.7... 

Scheme 4 Reagents and conditions i) Porcine pancreatic lipase, H20 ii) Ps. fluorescens lipase, H20.

CCL - now known as lipase from Candida rugosa (CRL)) but not porcine pancreatic lipase (PPL) (Figure 1.12). 

Analogously, ( )-152 was enzymatically hydrolyzed by porcine pancreatic lipase (PPL) to give (-)-75 in up to 93% ee, which could be further converted to (-)-methylenolactocin (11). 

Figure 11, Double kinetic resolution using enzymes with opposite enantioselectivity. PPL, porcine pancreatic lipase PLE, pig liver esterase.

Among the aldonolactone-based surfactants are aldonolactone-linked fatty esters which have been prepared by selective acylation of unprotected aldono-1,4-lac-tones or aldono-1,5-lactones, One of the first reported examples of this type of surfactant was applied to the enzymatic synthesis of 6-0-aUcanoylgluconolactones [35], Thus, 6-0-decanoyl- and 6-0-dodecanoyl- derivatives (21a and 21b, respectively, Scheme 8) were obtained in 26-27% yield by esterification of glucono-1,5-lactone (1) at C-6 with the corresponding 2,2,2-trichloroethyl carboxylate in the presence of porcine pancreatic lipase (PPL) as catalyst. Compounds 21a,b are soluble in water at 90-96°C but precipitate when cooled to 30-37°C, NMR and GC-MS analysis after dissolution and precipitation indicated the presence in the mixture of compound 21b, the glucono-1,4-lactone-derived ester 22, and the... 

Use of Pseudomonas cepacia lipase (lipase PS) or Porcine pancreatic lipase does allow for the enzymatic ROP of lactide. Matsumura and coworkers reported polymers with extraordinarily high molecular weights (Mw up to 270 kDa) and very narrow PDI (<1.3) [135-137]. However, high temperatures (130°C) were needed to achieve good conversions, and polymerizations proceeded only when conducted in bulk. It is conceivable that another non-enzymatic mechanism contributed in these polymerizations. In fact, Koning and coworkers synthesized copolymers... 

Kinetic resolutions by means of the selective formation or hydrolysis of an ester group in enzyme-catalyzed reactions proved to be a successful strategy in the enantioseparation of 1,3-oxazine derivatives. Hydrolysis of the racemic laurate ester 275 in the presence of lipase QL resulted in formation of the enantiomerically pure alcohol derivative 276 besides the (23, 3R)-enantiomer of the unreacted ester 275 (Equation 25) <1996TA1241 >. The porcine pancreatic lipase-catalyzed acylation of 3-(tu-hydroxyalkyl)-4-substituted-3,4-dihydro-2/7-l,3-oxazines with vinyl acetate in tetrahydrofuran (THF) took place in an enantioselective fashion, despite the considerable distance of the acylated hydroxy group and the asymmetric center of the molecule <2001PAC167, 2003IJB1958>. 

Several enzymatic processes have been developed. The DSM-Andeno method uses porcine pancreatic lipase, which selectively hydrolyses the (R)- +) glycidol with purities of at least 97% enantiomeric excess, suitable for subsequent chemical processing to prodnce enantiomerically pure products. 

Kinetic optical resolution of racemic alcohols and carboxylic acids by enzymatic acyl transfer reactions has received enormous attention in recent years56. The enzymes generally employed are commercially available lipases and esterases, preferentially porcine liver esterase (PLE) or porcine pancreatic lipase (PPL). Lipases from microorganisms, such as Candida cylindracea, Rhizopus arrhizus or Chromobacterium viscosum, are also fairly common. A list of suitable enzymes is found in reference 57. Standard procedures are described in reference 58. Some examples of the resolution of racemic alcohols are given39. 

The situation is summarized from a slightly different perspective in Figure 2.2. Here, data obtained using the same set of organic solvents have been plotted. The porcine pancreatic lipase-catalyzed transesterification of sulcatol (6-methyl-5-hepten-2-ol) with butyric acid trifluoroethyl ester [81] has been chosen (arbitrarily) to calibrate the solvents. It is clear that, irrespective of the solvent descriptors that one may aim to investigate, different systems are seen to respond differently to the same (change of) medium. 

Scheme 2.1 Kinetic resolution of glycidyl butyrate catalyzed by porcine pancreatic lipase, PPL The preferential conversion of (S)-glycidyl butyrate into (R)-glycidol and butyric acid results from the stereochemical nomenclature rules under the Cahn, Ingold, Prelog convention, the configuration around the chiral centre is not affected.

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