Classification of lattices withZ m symmetry

We consider then-dimensional Euclidean lattices withZ _m symmetries. It is shown that such lattices can be considered as ideals of some cyclotomic fields. Therefore we can translate problems about the above lattices into those about number theory. For alln (n22), we have obtained the classification of such lattices.     

Synthesis and characterization of aliphatic alpha-dithiones, di(1-adamantyl)- and di-tert-butylethanedithiones

2,3-Di(1-adamantyl)thiirene 1-oxide quickly reacted with Lawesson's reagent in CH2Cl2 at room temperature to provide di(1-adamantyl)ethanedithione (1) as thermally labile, violet crystals in 20% isolated yield. The use of CS2 as the solvent gave 1 in 46% isolated yield. The reaction in the presence of dimethyl acetylenedicarboxylate furnished dimethyl 4,5-di(1-adamantyl)-2,3-thiophenedicarboxylate in 51% yield. A tentative mechanism for the formation of 1 is proposed on the basis of the experimental observations. The structure of 1 was characterized on the basis of spectroscopic data (NMR, mass, IR, Raman, and UV/vis) and DFT calculations. 1 rearranged to 3,4-di(1-adamantyl)-1,2-dithiete quantitatively with kinetic parameters of DeltaH = 17.6 +/- 0.2 kcal mol-1, DeltaS = -23.0 +/- 0.7 cal K-1 mol-1, and DeltaG = 24.4 +/- 0.4 kcal mol-1. Peracid oxidation and Pt-complex formation of 1 are also reported.     

Nontotally symmetric trifurcation of an SN2 reaction pathway

A new type of reaction pathway which involves a nontotally symmetric trifurcation was found and investigated for a typical S_N2‐type reaction, NC^‐ + CH₃X → NC? CH₃ + X^‐ (X = F, Cl). A nontotally symmetric valley‐ridge inflection (VRI) point was located along the C_3v reaction path. For X = F, the minimum energy path (MEP) starting from the transition state (TS) leads to a second‐order saddle point with C_3v symmetry, which connects three product minima of C_s symmetry. For X = Cl, four product minima have been observed, of which three belong to C_s symmetry and one to C_3v symmetry. The branching path from the VRI point to the lower symmetry minima was determined by a linear interpolation technique. The branching mechanism is discussed based on the reaction path curvature and net atomic charges, and the possibility of a nonotally symmetric n‐furcation is discussed. © 2015 Wiley Periodicals, Inc.     

High‐resolution microanalysis of suspended particulate matter using a transition edge sensor microcalorimeter x‐ray spectrometer

Suspended particulate matter (SPM) collected in the urban area of Tokyo was analyzed using a transition edge sensor (TES) microcalorimeter x‐ray detector mounted on a FE‐SEM system. This prototype microcalorimeter spectrometer with an energy resolution of 19 eV identified some severe peak overlaps in the spectra measured by the traditional Si(Li) solid state detector, including S Kα with Pb Mα, Zn Lα with Na Kα, and Ti Kα with Ba Lα. In addition, the TES microcalorimeter showed good spatial resolution for the microanalysis of SPM. The focused ion beam(FIB) was successfully applied to fabricate a cross section of a single SPM particle. The chemical compositonal difference between surface and inner parts, and among different surface parts of the SPM was also determined. Through combination of the FIB technique and the TES microcalorimeter, we achieved a better understanding of the SPM. Copyright © 2009 John Wiley & Sons, Ltd.     

1-Aminoisoindole as a useful π-system elongation unit

Nitration of 4,7-ethanoisoindoles gave 1-nitro derivatives in moderate yields. Reduction of a nitro to amino group was successfully performed by sodium hydrosulfite in the case of ethyl 3-nitro-4,7-ethanoisoindole-1-carboxylate. The amino derivative was converted to benzylidenaminoisoindoles based on the retro Diels-Alder reaction. Their UV-vis spectra showed strong absorptions at 500-700 nm.     

A note on the span of Hadamard products of vectors

We give a new proof of Theorem 6 in [L. Qiu and X. Zhan, On the span of Hadamard products of vectors, Linear Algebra Appl. 422 (2007) 304–307].     

N2O and NO2 Formation in the Disproportionation of no over Ion Exchanged Cu-ZSM-5 at Lower Temperature

NO₃-type and NO₂-type adsorbed species are formed on Cu-ZSM-5 together with adsorbed O species at 523 K in the decomposition of NO accompanied by the evolution of N2, N₂O, and NO₂. This revised version was published online in June 2006 with corrections to the Cover Date.     

Total synthesis of (-)-neplanocin a by using lithium thiolate-initiated Michael-aldol tandem cyclization reaction.

(-)-Neplanocin A (1), S-adenosylhomocystein hydrolase inhibitor, was synthesized. The characteristic of this synthesis is a stereoselective construction of five-membered ring of neplanocin A by intramolecular aldol reaction of the lithium enolate that was generated by conjugate addition of lithium thiolate. TBS-protected chiral omega-oxo-alpha,beta-unsaturated ester 16, which was prepared from D-mannitol, was treated with 1.2 equiv of lithium benzylthiolate in THF at -20 degrees C to give three separable cyclization products in good yields and stereoselectivity. After conversions of protective groups, the benzylsulfanyl part of 21 was removed by oxidation to sulfoxide and subsequent thermal elimination to give the requisite double bond. Through the functional group transformations of 30, total synthesis of (-)-neplanocin A (1) was accomplished.     

Furopyridines. XXVIII. Reactions of 3-bromo derivatives of furo[2,3-b]-, -[3,2-b]-, -[2,3-c]- and -[3,2-c]pyridine and their N-oxides

Bromination of 3-bromofuro[2,3-b]- 1a , -[3,2-b]- 1b and - [3,2-c]pyridine 1d afforded the 2,3-dibromo derivatives 2a, 2b and 2d , while the -[2,3-c]- compound 1c did not give the dibromo derivative. Nitration of 1a-d gave the 2-nitro-3-bromo compounds 3a-d . The N-oxides 4a-d of 1a-d were submitted to the cyanation with trimethylsilyl cyanide to yield the corresponding α-cyanopyridine compound 6a-d . Chlorination of 4a and 4d with phosphorus oxychloride gave mainly the chloropyridine derivatives 7a, 7′a and 7d , while 4b and 4c gave mainly the chlorofuran derivatives 7′b and 7′c accompanying formation of the chloropyridine derivatives 7b, 7′b and 7c . Acetoxylation of 4a and 4b with acetic anhydride yielded the acetoxypyridine compounds 8a, 8′a and 8b , while 4c and 4d gave the acetoxypyridine 8′c, 8′d and 8′d , pyridone 8c and 8d , acetoxyfuran 8′c and dibromo compound 9c and 9′c.