Enzymatic Removal of Carboxyl Protecting Groups. 2. Cleavage of the Benzyl and Methyl Moieties

Abstract

[reaction: see text] Enzymes are versatile reagents for the efficient removal of methyl and benzyl protecting groups. An esterase from Bacillus subtilis (BS2) and a lipase from Candida antarctica (CAL-A) allow a mild and selective removal of these moieties in high yields without affecting other functional groups.

A Novel Alkaline Esterase fromSporosarcinasp. nov. Strain eSP04 Catalyzing the Hydrolysis of a Wide Variety of Aryl-carboxylic Acid Esters

“…17,18) Aryl-carboxylesterases, however, have many potential applications in various fields. They are attractive biocatalysts for the production of various aromas, fragrances, 19,20) and preservatives, 17,18) for the selective removal of protecting groups, 21,22) and in the field of health [23][24][25][26] as well as being potentially beneficial for the environment. It is thus of great interest to obtain a new arylcarboxylesterase with broad or unusual substrate specificities.…”

Bacillus subtilis Esterase (BS2) and its Double Mutant Have Different Selectivity in the Removal of Carboxyl Protecting Groups

“…[16] We previously showed that BS2 was able to remove selectively allyl ester from the gposition of substrate 3c in the presence of a-ethyl ester affording product 4a in 80% yield (entry 4, Table 2). [10] When an MOE or allyl group were at the a-position in the presence of a g-ethyl ester, a mixture of products was isolated from the hydrolysis of either substrate 3b or substrate 3d (entries 3 and 5, Table 2), indicating that apart from the nature of the group (chemoselectivity), the position (a-or g-) (regioselectivity) determines the products of the hydrolysis. Very interestingly, the n-propyl ester was preferentially cleaved either from the g-position of substrate 3e or from the a-position of substrate 3 f in the presence of an a-ethyl or g-ethyl ester, respectively (entries 6 and 8, Table 2).…”

“…[9] In addition, we have reported that BS2 was a versatile agent for the efficient removal of a variety of carboxyl protecting groups under mild conditions that avoid side reactions. [10,11] Point mutations in BS2 had a remarkable influence on both activity and enantioselectivity. [12] Most interestingly, the double mutant E188W/M193C of BS2 presented complete inversion of enantioselectivity towards acetylated tertiary alcohols.…”

Converting human carbonic anhydrase II into a benzoate ester hydrolase through rational redesign

“…Esterases have been evaluated for their potential for benzoate ester hydrolysis, with possible applications such as mild and selective removal of protecting groups, [2] and synthesis of benzoylated compounds. [3] Another intriguing possibility is to use esterases for treatment of cocaine overdoses.…”