01412nas a2200253   4500008004100000022001400041245011900055210006900174260010600243300001400349490000700363520042600370653002000796653002000816653003300836653003000869653002300899100002000922700002100942700002400963700002500987700001701012856012901029       2005                        eng d  a0040-402000aEfficient method for the synthesis of methyl 11 alpha-amino-3 alpha,7 alpha-diacetoxy-12-oxo-5 beta-cholan-24-oate0 aEfficient method for the synthesis of methyl 11 alphaamino3 alph  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcAPR  a3605-36120 v613 a<p>The synthesis of methyl 11 alpha-azido-3 alpha,7 alpha-diacetoxy-12-oxo-5 beta-cholan-24-oate, methyl 11 beta-azido-3 alpha,7 alpha-diacetoxy-12-oxo-5 beta-cholan-24-oate and methyl 11 alpha-amino-3 alpha,7 alpha-diacetoxy-12-oxo-5 beta-cholan-24-oate have been achieved. Mechanistic aspects for the decomposition of steroidal azidoketones to its enamines are discussed. (c) 2005 Elsevier Ltd. All rights reserved.</p>10a11-aminosteroid10a11-azidosteroid10abase catalyzed epimerization10aHIV-1 protease inhibitors10asteroidal enamines1 aSalunke, D., B.1 aHazra, Braja, G.1 aGonnade, Rajesh, G.1 aBhadbhade, Mohan, M.1 aPore, V., S.  uhttps://library.ncl.res.in/content/efficient-method-synthesis-methyl-11-alpha-amino-3-alpha7-alpha-diacetoxy-12-oxo-5-beta-002641nas a2200241   4500008004100000022001400041245014300055210006900198260007700267300001200344490000700356520171700363653001402080653001802094653001902112653001402131653002602145100002102171700002702192700002402219700002502243856013102268       2009                        eng d  a0947-653900aEnhancing intermolecular benzoyl-transfer reactivity in crystals by growing a ``reactive'' metastable polymorph by using a chiral additive0 aEnhancing intermolecular benzoyltransfer reactivity in crystals   aPO BOX 10 11 61, D-69451 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcNOV  a261-2690 v153 a<p>Racemic 2,4-di-O-benzoyl-myo-inositol-1,3,5-orthoacetate, which normally crystallizes in a monoclinic form (form I, space group P2(1)/n) could be persuaded to crystallize out as a metastable polymorph (form II, space group C2/c) by using a small amount of either D- or L- 2,4-di-O-benzoyl-myo-inositol-1,3,5-orthoformate as an additive in the crystallization medium. The structurally similar enantiomeric additive was chosen by the scrutiny of previous experimental results on the crystallization of racemic 2,4-di-O-benzoyl-myo-inositol-1,3,5-orthoacetate. Form II crystals call be thermally transformed to form I crystals at about 145 degrees C. The relative organization of the molecules in these dimorphs vary slightly in terms of the helical assembly of molecules, that is, electrophile (El)center dot center dot center dot nucleophile (Nu) and C-H center dot center dot center dot pi interactions, but these minor variations have a profound effect on the facility and specificity of benzoyl-group-transfer reactivity in the two crystal forms. While form II crystals undergo a clean intermolecular benzoyl-group-transfer reaction, form I crystals are less reactive and undergo non-specific benzoyl-group transfer leading to a Mixture of products. The role played by the additive in fine-tuning small changes that are required in the molecular packing opens up the possibility of creating new polymorphs that show varied physical and chemical properties. Crystals of D-2.6-di-O-benzoyl-myo-inositol-1,3,5-orthoformate (additive) did not show facile benzoyl-group-transfer reactivity (in contrast to the corresponding racemic compound) due to the lack of proper juxtaposition and assembly of molecules.</p>10aAcylation10acarbohydrates10aCrystal growth10acyclitols10asolid-state reactions1 aMurali, Chebrolu1 aShashidhar, Mysore, S.1 aGonnade, Rajesh, G.1 aBhadbhade, Mohan, M.  uhttps://library.ncl.res.in/content/enhancing-intermolecular-benzoyl-transfer-reactivity-crystals-growing-reactive-metastable-0