The standard (p-degrees = 0.1 M Pa) molar enthalpies of formation at 298.15 K in the gaseous state of some beta-ketoimines, RCOCH=C(CH3)NHR1, were determined from their enthalpies of combustion and of sublimation, DELTA(f)H(m)degrees(g)/kJ mol-1: R=CH3, {R1 = C6H5, -66.0 +/- 4.2; R1 = p-C6H4NO2, -98.9 +/- 5.0}: R = C6H5, {R1 = H, -48.7 +/- 3.5; R1 = CH3, -53.7 +/- 4.7; R1 = C6H5, 69.1 +/- 4.2). From these results it is shown that the increase in delocalization energy from R = CH3 to R = C6H5 matches the corresponding increase between acetylacetone and benzoylacetone. Crystal structures are reported for R = CH3, R1 = p-C6H4NO2, and R = C6H5 {R1 = H, R1 = CH3}, and show that those beta-ketoimines with R = C6H5 have a more delocalized structure in the -COCH=C(CH3)NH-moiety than those with R = CH3 in accord with the thermochemical results.

Thermolysis, at ca. 110 °C, of the strained norbornane furazan N-oxides (5)–(8) in toluene, saturated with sulphur dioxide, affords the isomeric 1,3-di-isocyantocyclopentanes (14)–(17). Product formation is explained by a mechanism involving cleavage of the furazan ring to cyclopentane-1,3- bis(nitrile oxides)[e.g.(9)], followed by 1,3-dipolar cycloaddition with SO2 to form bis-1,3,2,4-dioxathiazol-2-ones [e.g.(12)]. Subsequent extrusion of SO2 and rearrangement yields di-isocyanates [e.g.(14)] which were identified spectroscopically and by preparation of urethane and/or urea derivatives on reaction with alcohols and aniline. Compound (8) with aniline gives the cyclic biuret (20) rather than a bis-urea, the structure of the product being established by X-ray crystallography. In the absence of SO2 polymeric furoxans are formed.

AbstractDas Furazanoxid (V) wird ausgehend von Norbornen (I) durch Behandlung mit N2O3, thermische Isomerisierung des Nitronitroso‐Addukts (II) zum Nitro‐oxim (IV) und nachfolgende Dehydratisierung synthetisiert.

Chemischer InformationsdienstVolume 12, Issue 1 Physical Organic Chemistry ChemInform Abstract: CRYSTAL AND MOLECULAR STRUCTURES OF SILYL ISOCYANATE (AT -135°C) AND OF GERMYL ISOCYANATE (AT -95°C) M. J. BARROW, M. J. BARROWSearch for more papers by this authorE. A. V. EBSWORTH, E. A. V. EBSWORTHSearch for more papers by this authorM. M. HARDING, M. M. HARDINGSearch for more papers by this author M. J. BARROW, M. J. BARROWSearch for more papers by this authorE. A. V. EBSWORTH, E. A. V. EBSWORTHSearch for more papers by this authorM. M. HARDING, M. M. HARDINGSearch for more papers by this author First published: January 6, 1981 https://doi.org/10.1002/chin.198101072AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume12, Issue1January 6, 1981 RelatedInformation

Nitrile sulphides, generated by the thermal decarboxylation of 1,3,4-oxathiazol-2-ones, undergo 1,3-dipolar cycloaddition to the carbonyl group in chloral, hexachloroacetone and α,α,α-trifluoroacetophenone to yield 2,2,5-trisubstituted 1,3,4-oxathiazoles (18–76%). Characterisation of the products is based on analytical and spectrosopic evidence, and is confirmed for 5-phenyl-2-trichloromethyl-1,3,4-oxathiazole and 5-(p-methoxyphenyl)-2-phenyl-2-trifluoromethyl-1,3,4-oxathiazole by X-ray crystal structure analyses. The oxathiazole rings are planar, with a localised CN double bond.

Chemischer InformationsdienstVolume 11, Issue 25 Physical Organic Chemistry ChemInform Abstract: MOLECULAR STRUCTURE OF GERMYLCYCLOPENTADIENE IN THE CRYSTALLINE PHASE AT 160 K AND IN THE GAS PHASE M. J. BARROW, M. J. BARROWSearch for more papers by this authorE. A. V. EBSWORTH, E. A. V. EBSWORTHSearch for more papers by this authorM. M. HARDING, M. M. HARDINGSearch for more papers by this authorD. W. H. RANKIN, D. W. H. RANKINSearch for more papers by this author M. J. BARROW, M. J. BARROWSearch for more papers by this authorE. A. V. EBSWORTH, E. A. V. EBSWORTHSearch for more papers by this authorM. M. HARDING, M. M. HARDINGSearch for more papers by this authorD. W. H. RANKIN, D. W. H. RANKINSearch for more papers by this author First published: June 24, 1980 https://doi.org/10.1002/chin.198025072AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume11, Issue25June 24, 1980 RelatedInformation

AbstractBei ‐110°C sind Kristalle der Titelverbindung monoklin (P2,/n, Z=4).

THE cycloamyloses (CnA) are α-1, 4-linked cyclic oligomers of D-glucopyranose, which have attracted considerable attention as enzyme models1. These doughnut-shaped molecules have the primary hydroxyl groups from the 6-position of the glucose residues at one side of the torus, and the secondary hydroxyl groups from the 2- and 3-positions at the other. On the inside of the cavity there is a ring of CH groups, a ring of glycosidic oxygens, and a further ring of CH groups, resulting in a hydrophobic ether-like interior. The ability of the cycloamyloses to form stable complexes with a variety of organic compounds by inclusion within the hydrophobic cavity has prompted their use as models for the active sites of enzymes. Of particular interest is the observation that they can accelerate the release of phenols from a variety of aryl esters2 and of anilines from anilides3 by a reaction pathway similar to that observed for the hydrolytic enzyme α-chymotrypsin. Furthermore, a marked degree of substrate specificity is observed: thus, the cleavage of meta-substituted aryl acetates is accelerated more than that of their para-analogues2. It has been suggested that this specificity is due to the closer positioning of the nucleophilic secondary hydroxyl group of the cycloamylose to the ester carbonyl in the meta complex than in the para complex2. To test the validity of this hypothesis we have made an X-ray crystallographic study of a series of meta- and para-substituted acetanilides and report here on the 1:1 complex of C7 A with p-nitroacetanilide (PNA).

M. J. Barrow, S. Cradock, E. A. V. Ebsworth and M. M. Harding, J. Chem. Soc., Chem. Commun., 1977, 744 DOI: 10.1039/C39770000744

The structure of dl-histidine, C 6 H 9 N 3 O 2 , has been determined from three-dimensional X-ray diffraction data and refined until R = 0.13 and standard deviations in bond lengths are ∼ 0.005 Å. The crystals are monoclinic, P 2 1 / c , with a = 8.983, b = 8.087, c = 9.415 Å, β = 97.65°. The histidine molecule is nearly fully extended but the conformation is not the same as that of the chemically identical histidine molecules in crystalline L-histidine.

The crystal structure of the title compound has been determined using three dimensional X-ray diffraction data. The structure was solved by direct methods. The positional and anisotropic thermal parameters were refined using a full matrix least squares procedure to give an R factor of 0·097 for 1926 reflections. Standard deviations were ±0·004 Å in the bond lengths and ±0·2° in the bond angles. The geometry of the molecule is compared with that of other monosaccharide structures and the effect of the 3,6-anhydro-bridge is discussed. Crystal data: orthorhombic space group P212121, Z= 4, a= 9·46 ± 0·01, b= 12·05 ± 0·01, c= 6·93 ± 0·015 Å.

J. Bain and M. M. Harding, J. Chem. Soc., 1965, 4025 DOI: 10.1039/JR9650004025

P. J. Fisher, N. E. Taylor and M. M. Harding, J. Chem. Soc., 1960, 2303 DOI: 10.1039/JR9600002303