01109nas a2200181   4500008004100000022001400041245007600055210006900131260011100200300001400311490000700325520039300332100002500725700002800750700002400778700002200802856010300824       2014                        eng d  a1466-803300aCapturing a novel metastable polymorph of the anticancer drug gefitinib0 aCapturing a novel metastable polymorph of the anticancer drug ge  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcAUG   a8638-86410 v163 a<p>Gefitinib, a life-extending anticancer drug, exhibits solvent-mediated conformational polymorphism to yield stable (form I) and novel metastable (form II) polymorphs. Crystal structure analysis revealed 3D isostructurality in the molecular organization of the polymorphs, and the metastable polymorph undergoes a crystal-to-crystal thermal phase transition to the stable polymorph.</p>1 aThorat, Shridhar, H.1 aPatwadkar, Manjusha, V.1 aGonnade, Rajesh, G.1 aVaidhyanathan, R.  uhttp://library.ncl.res.in/content/capturing-novel-metastable-polymorph-anticancer-drug-gefitinib-004389nas a2200265   4500008004100000022001400041245017900055210006900234260007400303300001400377490000700391520332100398653003003719653004303749653001403792653002203806653002103828653002603849653002303875653002803898100002503926700002403951700002403975856012403999       2015                        eng d  a2053-229600aCrystal structures of the pyrazinamide-p-aminobenzoic acid (1/1) cocrystal and the transamidation reaction product 4-(pyrazine-2-carboxamido)-benzoic acid in the molten state0 aCrystal structures of the pyrazinamidepaminobenzoic acid 11 cocr  a2 ABBEY SQ, CHESTER, CH1 2HU, ENGLANDbINT UNION CRYSTALLOGRAPHYcNOV  a1010-U2760 v713 a<p>The synthesis of pharmaceutical cocrystals is a strategy to enhance the performance of active pharmaceutical ingredients (APIs) without affecting their therapeutic efficiency. The 1: 1 pharmaceutical cocrystal of the antituberculosis drug pyrazinamide (PZA) and the cocrystal former p-aminobenzoic acid (p-ABA), C7H7NO2- C5H5N3O, (1), was synthesized successfully and characterized by relevant solid-state characterization methods. The cocrystal crystallizes in the monoclinic space group P21/n containing one molecule of each component. Both molecules associate via intermolecular O-H center dot center dot center dot O and NH center dot center dot center dot O hydrogen bonds [O center dot center dot center dot O = 2.6102 (15)angstrom and O-H center dot center dot center dot O = 168.3 (19)degrees; N center dot center dot center dot O = 2.9259 (18) angstrom and N-H center dot center dot center dot O = 167.7 (16)degrees] to generate a dimeric acidamide synthon. Neighbouring dimers are linked centrosymmetrically through N-H center dot center dot center dot O interactions [N center dot center dot center dot O = 3.1201 (18) angstrom and N-H center dot center dot center dot O = 136.9 (14)degrees] to form a tetrameric assembly supplemented by C-H center dot center dot center dot N interactions [C center dot center dot center dot N = 3.5277 (19) angstrom and C-H center dot center dot center dot N = 147 degrees]. Linking of these tetrameric assemblies through N-H center dot center dot center dot O [N center dot center dot center dot O = 3.3026 (19) angstrom and N-H center dot center dot center dot O = 143.1 (17)degrees], NH center dot center dot center dot N [N center dot center dot center dot N = 3.221 (2) angstrom and N-H center dot center dot center dot N = 177.9 (17)degrees] and C-H center dot center dot center dot O [C center dot center dot center dot O = 3.5354 (18) angstrom and C-H center dot center dot center dot O = 152 degrees] interactions creates the twodimensional packing. Recrystallization of the cocrystals from the molten state revealed the formation of 4-(pyrazine-2-carboxamido) benzoic acid, C12H9N3O3, (2), through a transamidation reaction between PZA and p-ABA. Carboxamide (2) crystallizes in the triclinic space group P1 with one molecule in the asymmetric unit. Molecules of (2) form a centrosymmetric dimeric homosynthon through an acid-acid O-H center dot center dot center dot O hydrogen bond [O center dot center dot center dot O = 2.666 (3) angstrom and O-H center dot center dot center dot O = 178 (4) degrees]. Neighbouring assemblies are connected centrosymmetrically via a C-H center dot center dot center dot N interaction [C center dot center dot center dot N = 3.365 (3) angstrom and C-H center dot center dot center dot N = 142 degrees] engaging the pyrazine groups to generate a linear chain. Adjacent chains are connected loosely via C-H center dot center dot center dot O interactions [C center dot center dot center dot O = 3.212 (3) angstrom and CH center dot center dot center dot O = 149 degrees] to generate a two-dimensional sheet structure. Closely associated two-dimensional sheets in both compounds are stacked via aromatic pi-stacking interactions engaging the pyrazine and benzene rings to create a threedimensional multi-stack structure.</p>10aacid-amide hetero-synthon10aactive pharmaceutical ingredient (API)10acocrystal10acrystal structure10ahydrogen bonding10amolten-state reaction10apowder diffraction10atransamidation reaction1 aThorat, Shridhar, H.1 aSahu, Sanjay, Kumar1 aGonnade, Rajesh, G.  uhttp://library.ncl.res.in/content/crystal-structures-pyrazinamide-p-aminobenzoic-acid-11-cocrystal-and-transamidation-101013nas a2200157   4500008004100000245012800041210006900169260000800238300001600246490000700262520040400269100001600673700002500689700002600714856011500740       2016                        eng d00aCu-Catalyzed iminative hydroolefination of unactivated alkynes en route to 4-imino-tetrahydropyridines and 4-aminopyridines0 aCuCatalyzed iminative hydroolefination of unactivated alkynes en  cOCT  a13475-134780 v523 aA general method for synthesizing 4-imino tetrahydropyridine derivatives is achieved, from readily available beta-enaminones and sulfonyl azides, which comprises a sequential copper catalyzed ketenimine formation and its hitherto inaccessible intramolecular hydrovinylation. The products are shown as ready precursors for highly valuable 4-sulfonamidopyridine derivatives via DDQ mediated oxidation.1 aKumar, Ravi1 aThorat, Shridhar, H.1 aReddy, Maddi, Sridhar  uhttp://library.ncl.res.in/content/cu-catalyzed-iminative-hydroolefination-unactivated-alkynes-en-route-4-imino