01817nas a2200241 4500008004100000022001400041245013000055210006900185260010600254300001400360490000700374520089400381653001401275653001301289653001301302653001501315653002101330653002401351100002301375700002501398700002701423856012501450 2009 eng d a0040-402000aRegioselective O-acylation of myo-inositol 1,3,5-orthoesters: dependence of regioselectivity on the stoichiometry of the base0 aRegioselective Oacylation of myoinositol 135orthoesters dependen aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcMAR a2703-27100 v653 a

A metal mediated unusual 1-3 acyl migration from C4-O to C2-OH of myo-inositol 1,3,5-orthoformate was observed during the alkylation of racemic 4-O-benzoyl-myo-inositol 1,3,5-orthoformate. This has been exploited for the selective esterification of either the C4(6)-OH or the C2-OH of myo-inositol by varying the amount of the base used. While the use of 1 equiv of the base (sodium hydride or potassium tert-butoxide) for the acylation of myo-inositol orthoesters gives the corresponding C4-ester exclusively, the use of two or more equivalents of base for the same reaction gives the C2-ester exclusively. The relatively higher stability of the alkoxide of racemic 2-O-acyl-myo-inositol 1,3,5-orthoester as compared to the alkoxide of 4-O-acyl-myo-inositol 1,3,5-orthoester is suggested to be responsible for the observed isomerization. (c) 2009 Elsevier Ltd. All rights reserved.

10aAcylation10aCyclitol10aInositol10aOrthoester10aRegioselectivity10atransesterification1 aSureshan, Kana, M.1 aDevaraj, Subramanian1 aShashidhar, Mysore, S. uhttps://library.ncl.res.in/content/regioselective-o-acylation-myo-inositol-135-orthoesters-dependence-regioselectivity-001473nas a2200193 4500008004100000022001400041245016300055210006900218260011000287300001200397490000700409520062300416100002101039700002401060700001701084700002401101700002301125856013101148 2012 eng d a1466-803300aStrength from weakness: the role of CH center dot center dot center dot N hydrogen bond in the formation of wave-like topology in crystals of aza-heterocycles0 aStrength from weakness the role of CH center dot center dot cent aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT a519-5240 v143 a

Crystal engineering has succeeded in the design and construction of various architectures such as tapes, ribbons, rosettes, layers etc. Though wavy layer packing is known to occur in crystals, no crystal engineering attempts have been ventured to create wavy layer topology in crystals. Aromatic nitrogen heterocyclics (ANHs) are known to preferentially self assemble in lateral fashion through edge-to-edge CH center dot center dot center dot N hydrogen bonds. Exploiting this preferential lateral assembly of ANHs, we have engineered wavy layer architectures in the crystals of various substituted quinolines.

1 aShivakumar, Kota1 aVidyasagar, Adiyala1 aNaidu, Andra1 aGonnade, Rajesh, G.1 aSureshan, Kana, M. uhttps://library.ncl.res.in/content/strength-weakness-role-ch-center-dot-center-dot-center-dot-n-hydrogen-bond-formation-wave-000891nas a2200217 4500008004100000022001400041245015400055210006900209260007700278300001400355490000700369653002000376653002000396653001900416653001700435653001800452100002800470700002400498700002300522856012800545 2012 eng d a1433-785100aTopochemical click reaction: spontaneous self-stitching of a monosaccharide to linear oligomers through lattice-controlled azide-alkyne cycloaddition0 aTopochemical click reaction spontaneous selfstitching of a monos aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcAPR a4362-43660 v5110aClick chemistry10agreen chemistry10apolymerization10apseudosugars10atopochemistry1 aPathigoolla, Atchutarao1 aGonnade, Rajesh, G.1 aSureshan, Kana, M. uhttps://library.ncl.res.in/content/topochemical-click-reaction-spontaneous-self-stitching-monosaccharide-linear-oligomers-001117nas a2200157 4500008004100000022001400041245020400055210006900259260011000328300001400438490000700452520032300459100002300782700002400805856013000829 2013 eng d a1466-803300aWeak becomes strong: remarkable strength of C-H center dot center dot center dot pi hydrogen bond in the presence of O-H center dot center dot center dot O hydrogen bonds in the crystal stabilization0 aWeak becomes strong remarkable strength of CH center dot center  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcJAN a1676-16790 v153 a

We report crystallographic evidence for the significance of C-H center dot center dot center dot pi hydrogen bonds in the crystal stabilization of 1,4-di-O-benzoyl-myo-inositol. The strength of this otherwise weak hydrogen bond matches with the strength of O-H center dot center dot center dot O hydrogen bonds.

1 aSureshan, Kana, M.1 aGonnade, Rajesh, G. uhttps://library.ncl.res.in/content/weak-becomes-strong-remarkable-strength-c-h-center-dot-center-dot-center-dot-pi-hydrogen-001646nas a2200229 4500008004100000022001400041245010700055210006900162260000800231300001400239490000700253520085700260653001901117653002101136653001901157653002701176653001401203100002201217700002401239700002301263856013001286 2020 eng d a1433-785100aCrystal-to-crystal synthesis of helically ordered polymers of trehalose by topochemical polymerization0 aCrystaltocrystal synthesis of helically ordered polymers of treh cFEB a2897-29030 v593 a

The synthesis of crystalline helical polymers of trehalose via topochemical azide-alkyne cycloaddition (TAAC) of a trehalose-based monomer is presented. An unsymmetrical trehalose derivative having azide and alkyne crystallizes in two different forms having almost similar packing. Upon heating, both the crystals undergo TAAC reaction to form crystalline polymers. Powder X-ray diffraction (PXRD) studies revealed that the monomers in both the crystals polymerize in a crystal-to-crystal fashion; circular dichroism (CD) studies of the product crystals revealed that the formed polymer is helically ordered. This solvent-free, catalyst-free polymerization method that eliminates the tedious purification of the polymeric product exemplifies the advantage of topochemical polymerization reaction over traditional solution-phase polymerization.

10aClick reaction10ahelical polymers10apolysaccharide10atopochemical reactions10atrehalose1 aHema, Kuntrapakam1 aGonnade, Rajesh, G.1 aSureshan, Kana, M. uhttps://library.ncl.res.in/content/crystal-crystal-synthesis-helically-ordered-polymers-trehalose-topochemical-polymerization