01138nas a2200229   4500008004100000022001400041245004700055210004700102260010600149300001400255490000700269520039000276653001800666653000800684653001700692653001800709100002500727700002300752700002600775700002600801856008100827       2012                        eng d  a0040-403900aEfficient total synthesis of calothrixin B0 aEfficient total synthesis of calothrixin B  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJUN  a2894-28960 v533 a<p>An efficient synthesis of calothrixin B (2) is demonstrated starting from 9H-carbazol-4-ol, having two one-pot reaction sequences as key steps. As a novel observation, DMF-methanol was shown to be a hydride donor for reduction of aldehyde to alcohol. Unexpectedly, nucleophilic substitution of benzyloxy by methoxy group was observed. (C) 2012 Elsevier Ltd. All rights reserved.</p>10aCalothrixin B10aCAN10aDMF-methanol10aHydride donor1 aBhosale, Shrikar, M.1 aGawade, Rupesh, L.1 aPuranik, Vedavati, G.1 aKusurkar, Radhika, S.  uhttps://library.ncl.res.in/content/efficient-total-synthesis-calothrixin-b-001107nas a2200241   4500008004100000022001400041245009100055210006900146260010600215300001400321490000700335520023000342653000600572653001600578653002200594653000800616100002500624700002100649700002300670700002600693700002600719856012000745       2012                        eng d  a0040-403900aNew synthetic route for 1,2-diketo compounds using unexpected C-C bond cleavage by PCC0 aNew synthetic route for 12diketo compounds using unexpected CC b  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcSEP  a5327-53300 v533 a<p>An efficient method has been established for the preparation of 1,2-diketones by unexpected C-C bond cleavage in 4-keto-2-hydroxy esters using pyridiniumchlorochromate (PCC). (c) 2012 Elsevier Ltd. All rights reserved.</p>10a110a2-Diketones10aC-C bond cleavage10aPCC1 aBhosale, Shrikar, M.1 aMomin, Aadil, A.1 aGawade, Rupesh, L.1 aPuranik, Vedavati, G.1 aKusurkar, Radhika, S.  uhttps://library.ncl.res.in/content/new-synthetic-route-12-diketo-compounds-using-unexpected-c-c-bond-cleavage-pcc-001567nas a2200253   4500008004100000022001400041245011200055210006900167260010600236300001200342490000700354520061100361653001700972653001800989653001401007653002801021653002101049100002501070700002101095700002101116700002401137700002601161856012601187       2014                        eng d  a0040-403900aUnexpected observations during the total synthesis of calothrixin B-sodium methoxide as a source of hydride0 aUnexpected observations during the total synthesis of calothrixi  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJAN  a155-1620 v553 a<p>During the total synthesis of calothrixin B, various novel and unexpected results were noticed such as cleavage of C-N bond in imine using sodium cyanoborohydride, sodium methoxide as a hydride source for reduction, deformylation in the presence of bromine, and deacylation using ceric ammonium nitrate (CAN). A detailed mechanism has been proposed for the unexpected results and a few of them are generalized. Temperature dependent NMR studies have been carried out for confirmation of the structure of one of the intermediates in the synthetic sequence. (C) 2013 Elsevier Ltd. All rights reserved.</p>10aAzoxybenzene10aCalothrixin B10areduction10aSodium cyanoborohydride10aSodium methoxide1 aBhosale, Shrikar, M.1 aMomin, Aadil, A.1 aKunjir, Shrikant1 aRajamohanan, P., R.1 aKusurkar, Radhika, S.  uhttps://library.ncl.res.in/content/unexpected-observations-during-total-synthesis-calothrixin-b-sodium-methoxide-source-0