1.Synthesis of a family of spirocyclic scaffolds: building blocks for the exploration of chemical space.
Kumar S1, Thornton PD, Painter TO, Jain P, Downard J, Douglas JT, Santini C. J Org Chem. 2013 Jul 5;78(13):6529-39. doi: 10.1021/jo400738b. Epub 2013 Jun 26.
This report describes the preparation of a series of 17 novel racemic spirocyclic scaffolds that are intended for the creation of compound libraries by parallel synthesis for biological screening. Each scaffold features two points of orthogonal diversification. The scaffolds are related to each other in four ways: (1) through stepwise changes in the size of the nitrogen-bearing ring; (2) through the oxidation state of the carbon-centered point of diversification; (3) through the relative stereochemical orientation of the two diversification sites in those members that are stereogenic; and (4) through the provision of both saturated and unsaturated versions of the furan ring in the scaffold series derived from 3-piperidone. The scaffolds provide incremental changes in the relative orientation of the diversity components that would be introduced onto them. The scaffolds feature high sp(3) carbon content which is essential for the three-dimensional exploration of chemical space.
2.Chiral alcohol production by NADH-dependent phenylacetaldehyde reductase coupled with in situ regeneration of NADH.
Itoh N1, Matsuda M, Mabuchi M, Dairi T, Wang J. Eur J Biochem. 2002 May;269(9):2394-402.
Phenylacetaldehyde reductase (PAR) produced by styrene-assimilating Corynebacterium strain ST-10 was used to synthesize chiral alcohols. This enzyme with a broad substrate range reduced various prochiral aromatic ketones and beta-ketoesters to yield optically active secondary alcohols with an enantiomeric purity of more than 98% enantiomeric excess (e.e.). The Escherichia coli recombinant cells which expressed the par gene could efficiently produce important pharmaceutical intermediates; (R)-2-chloro-1-(3-chlorophenyl)ethanol (28 mg.mL-1) from m-chlorophenacyl chloride, ethyl (R)-4-chloro-3-hydroxy butanoate) (28 mg.mL-1) from ethyl 4-chloro-3-oxobutanoate and (S)-N-tert-butoxycarbonyl(Boc)-3-pyrrolidinol from N-Boc-3-pyrrolidinone (51 mg.mL-1), with more than 86% yields. The high yields were due to the fact that PAR could concomitantly reproduce NADH in the presence of 3-7% (v/v) 2-propanol in the reaction mixture. This biocatalytic process provided one of the best asymmetric reductions ever reported.
3.Syntheses of new modified Phe-Pro peptides. Use of proline replacements in potential HIV inhibitors.
Bouygues M1, Medou M, Quéléver G, Chermann JC, Camplo M, Kraus JL. Bioorg Med Chem Lett. 1998 Feb 3;8(3):277-80.
The syntheses consisting of replacement of proline amino acid by a 3-pyrrolidinone ring in Phe-Pro analogues are described. Preliminary anti-HIV studies demonstrated the potential activity of this new class of compounds.
4.Cloning, sequence analysis, and expression in Escherichia coli of gene encoding N-Benzyl-3-pyrrolidinol dehydrogenase from Geotrichum capitatum.
Yamada-Onodera K1, Kojima K, Takase Y, Tani Y. J Biosci Bioeng. 2007 Nov;104(5):379-84.
The gene encoding N-benzyl-3-pyrrolidinol dehydrogenase (DDBJ/EMBL/GenBank accession no. AB294179), a useful biocatalyst for producing (S)-N-benzyl-3-pyrrolidinol, was cloned from the genomic DNA of Geotrichum capitatum JCM 3908. The gene contained an open reading frame consisting of 1023 nucleotides corresponding to 340 amino acid residues. The subunit molecular weight was calculated to be 39,000. The predicted amino acid sequence did not have significant similarity to those of N-benzyl-3-pyrrolidinone reductases reported previously. From 30 mM N-benzyl-3-pyrrolidinone, (S)-N-benzyl-3-pyrrolidinol was obtained with a yield >99.9% and an enantiomeric excess >99.9% in 1-h and 2-h reactions without NADH addition by the resting cells of Escherichia coli HB 101 strains harboring the expression plasmids pSG-POBS and pSF-POBS that possess the glucose dehydrogenase gene and formate dehydrogenase gene as an NADH-reproducing system, respectively, besides the N-benzyl-3-pyrrolidinol dehydrogenase gene.