Loreto Salazar

A new application of Candida antarctica lipase for obtaining natural homochiral BBAs aryloxypropanolamine

Abstract CAL offers increased ee, together with broad substrate structural tolerance that makes it a firm candidate for the resolution of BBAs of type 1 .

Resolution of 3-α-naphthoxy-1,2-propanediol using Candida antarctica lipase

Abstract The stereochemistry of the Candida antarctica lipase B (CALB) catalyzed resolution of diacetate 1 or diol 4 was analyzed. The primary and secondary acetate hydrolyses were studied separately using monoacetates 2 and 3 . The enantioselectivity of CALB was found to be lower towards primary rather than secondary acetates/alcohols. The steric course of the process is discussed.

INFLUENCE OF THE N-MOM GROUP IN THE ENANTIOSELECTIVE LIPASE CATALYZED METHANOLYSIS OF RACEMIC 1,4-DIHYDROPYRIDINE DICARBOXYLATES

Abstract The hydrolysis of ( RS )-acetoxymethyl-ethyl-2,6-dimethyl-4-phenyl-1,4-dihydropyridine-3,5-dicarboxylates, N-methoxymethylated and N-unsubstituted has been carried out using lipases AK and PS from Pseudomonas . The presence of N-MOM changed the enantiopreference of lipase AK but not of lipase PS. The observed enantiopreference of the lipases is not changed by the nature of the organic solvent or the temperature.

The structure of N-(azol-N-yl) formamides: a crystallographic and dynamic NMR spectroscopy study

The molecular structures of N-(pyrazol-1-yl) formamide 1[C4H5N3O, orthorhombic, space group P212121, a= 5.269(8). b= 8.039(8). c= 12.79(2), Z= 4] and N-(indazol-1 -yl) formamide, 5[C8H7N3O, monoclinic, space group P21/c, a= 9.065(2). b= 11.089(7), c= 8.463(7), Z= 4] have been solved by X-ray crystallography. Regarding the amide bond, both compounds exist in the Z configuration, a configuration which also prevails in solution for all the N-H azolyl formamides whilst the N-substituted derivatives prefer the E configuration. The rotation barriers about the amide bond are similar although a little lower than those of N-phenylformamide and N-methyl-N-phenylformamide, a fact that may be related to the electronic properties of the N-azolyl substituent.

Enantiospecific hydrolysis of esters of nonsteroidal antiinflammatory drugs using lipase of Candida cylindracea

Abstract Enantiospecific hydrolysis of esters of 2-arylpropionic acids with antiinflammatory activity has been carried out. The racemic acids were synthetized by Willgerodt—Kindler synthesis in good yields. The enzymatic hydrolysis of the esters was carried out in a batch reactor with 0.2 M substrate concentration.

Rearrangement of 1-amino- and 1-alkylamino-pyrazoles to 5-aminopyrazoles

Rearrangement of 1-aminopyrazole and 1-alkylaminopyrazoles into the corresponding 5-aminopyrazoles has been achieved in 48% aqueous hydrobromic acid. The reaction, occurring through a ring opening–ring closure mechanism, constitutes a new and unambiguous procedure for the preparation of 1-substituted 5-aminopyrazoles. The products have been identified on the basis of 1H and 13C n.m.r. spectroscopic results and comparison with authentic samples.