@article { ISI:000249453100008, title = {4-Formylazetidin-2-one as a useful building block for the formal synthesis of xylo-(2S,3R,4R)-phytosphingosine and threo-(2S,3S)-sphingosine}, journal = {Synthesis-Stuttgart }, volume = {17}, number = {17}, year = {2007}, month = {SEP}, pages = {2631-2636}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

Stereoselective formal synthesis of xylo-(2S,3R,4R)-phytosphingosine and threo-(2S,3S)-sphingosine is described starting from an enantiopure formyl-substituted P-lactam. Grignard reaction of the N-Boc-protected-beta-lactam carbonyl group, followed by further transformations, provides a common intermediate for xylo-(2S,3R,4R)-phytosphingosine and threo-(2S,3S)-sphingosine.

}, keywords = {azetidin-2-one, beta-lactam, Grignard reaction, Phytosphingosine, Sphingosine}, issn = {0039-7881}, doi = {10.1055/s-2007-983815}, author = {Kale, Ajaykumar S. and Sakle, Prathmesh S. and Gumaste, Vikas K. and Deshmukh, Abdul Rakeeb A. S.} } @article { ISI:000244732800019, title = {Stereoselective synthesis of 3-alkylidene/alkylazetidin-2-ones from azetidin-2,3-diones}, journal = {Tetrahedron}, volume = {63}, number = {11}, year = {2007}, month = {MAR}, pages = {2524-2534}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Azetidin-2,3-diones have been used as synthons for the synthesis of C-3 alkylidene/alkylazetidin-2-ones. Some of the 3-alkylazetidin-2-ones are well known for their cholesterol absorption inhibitor activity. A regio and stereoselective Grignard reaction on a keto group followed by dehydration using PPh3/CCl4 reagent is a key step in this synthesis. Hydrogenation of the 3-alkylideneazetidin-2-ones provided stereoselectively cis-3-alkylazetidin-2-ones in very good yields. (c) 2006 Published by Elsevier Ltd.

}, keywords = {3-diones, azetidin-2, azetidin-2-ones, beta-lactam, Grignard reaction}, issn = {0040-4020}, doi = {10.1016/j.tet.2006.12.010}, author = {Tiwari, Dharmendra Kumar and Shaikh, Ashif Y. and Pavase, Laxmikant S. and Gumaste, Vikas K. and Deshmukh, Abdul Rakeeb A. S.} } @article { ISI:000267070700046, title = {Enantioselective total synthesis of (2S,3R,4R)-D-xylo-phytosphingosine from substituted azetidin-2-one}, journal = {Tetrahedron Letters}, volume = {50}, number = {26}, year = {2009}, month = {JUL}, pages = {3296-3298}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Enantiomerically pure (2S,3R,4R)-D-xylo phytosphingosine is synthesized in 36\% overall yield in seven steps from known beta-lactam (8) derived from D-mannitol triacetonide. (C) 2009 Elsevier Ltd. All rights reserved.

}, keywords = {beta-lactam, Enantioselective synthesis, Sphingosine, Wittig reaction}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2009.02.050}, author = {Pandey, Ganesh and Tiwari, Dharmendra Kumar} } @article { ISI:000367612000010, title = {Penicillin acylases revisited: importance beyond their industrial utility}, journal = {Critical Reviews In Biotechnology}, volume = {36}, number = {2}, year = {2016}, month = {MAR}, pages = {303-316}, publisher = {TAYLOR \& FRANCIS LTD}, address = {4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND}, abstract = {

It is of great importance to study the physiological roles of enzymes in nature; however, in some cases, it is not easily apparent. Penicillin acylases are pharmaceutically important enzymes that cleave the acyl side chains of penicillins, thus paving the way for production of newer semi-synthetic antibiotics. They are classified according to the type of penicillin (G or V) that they preferentially hydrolyze. Penicillin acylases are also used in the resolution of racemic mixtures and peptide synthesis. However, it is rather unfortunate that the focus on the use of penicillin acylases for industrial applications has stolen the spotlight from the study of the importance of these enzymes in natural metabolism. The penicillin acylases, so far characterized from different organisms, show differences in their structural nature and substrate spectrum. These enzymes are also closely related to the bacterial signalling phenomenon, quorum sensing, as detailed in this review. This review details studies on biochemical and structural characteristics of recently discovered penicillin acylases. We also attempt to organize the available insights into the possible in vivo role of penicillin acylases and related enzymes and emphasize the need to refocus research efforts in this direction.

}, keywords = {beta-lactam, choloyl glycine, in vivo role, Ntn hydrolases, pathogenicity, quorum sensing, regulation, signalling}, issn = {0738-8551}, doi = {10.3109/07388551.2014.960359}, author = {Avinash, Vellore Sunder and Pundle, Archana Vishnu and Ramasamy, Sureshkumar and Suresh, Cheravakkattu Gopalan} }