Copper(II)-catalyzed aerobic oxidation of primary alcohols to aldehydes in ionic liquid [bmpy]PF6

A room-temperature aerobic oxidation of primary alcohols to aldehydes catalyzed by the three-component system acetamido-TEMPO/Cu(ClO(4))(2)/DMAP in the ionic liquid [bmpy]PF(6) has been developed, and the catalysts can be recycled and reused for five runs without any significant loss of catalytic activity. [reaction: see text]     

Ring closure reaction of 4-(2-hydroxyanilino)-2-phenyl-5-pyrimidinecarboxylic acid with acetic anhydride. Synthesis of pyrimido[5,4-c] [1,5]benzoxazepin-5(11H)ones

Syntheses of 11-acety1-2-phenylpyrimido[5,4-c][1,5]benzoxazepin-5(11H)one ( 16a ) and analogs ( 16b,c, 22 ) were described. The reaction of 4-chloro-2-phenyl-5-pyrimidinecarboxylic acid ethyl ester ( 7 ) with 2-aminophenol afforded 4-(2-hydroxyanilino)-2-phenyl-5-pyrimidine-carboxylic acid ethyl ester ( 8a ). The latter was also prepared by catalytic reduction of 4-(2-nitrophenoxy)-2-phenyl-5-pyrimidinecarboxylic acid ethyl ester ( 9 ), which was obtained from 7 and 2-nitrophenol. Involvement of 4-(2-aminophenoxy)-2-phenyl-5-pyrimidinecarboxylic acid ethyl ester ( 12a ) in this reduction as an intermediate was demonstrated by an independent synthesis of 12a and its subsequent rearrangement to 8a. Hydrolysis of 8a or 12a gave 4-(2-hydroxyanilino)-2-phenyl-5-pyrimidinecarboxylic acid ( 15a ). Reaction of 15a with acetic anhydride afforded 16a , the first member of a novel ring system, the pyrimido[5,4- c ][1,5]-benzoxazepin. Additional examples ( 16b,c ) were prepared similarly. The corresponding 11-ethyl derivative ( 22 ) was prepared in similar fashion, starting with 7 and 2-ethylaminophenol. A possible reaction mechanism for the formation of 16a-c from 15a-c and acetic anhydride was discussed.     

Synthesis of 1,2,4-oxadiazines and their rearrangement to pyrimidines

Several amide oximes underwent condensation reactions with dimethyl acetylene dicarboxylate to afford 1:1 adducts. Under basic conditions, these adducts underwent ring closure to afford several methyl [3-(substituted)-4,5-dihydro-5-oxo-6H-1,2,4-oxadiazin-6-ylidene]acetates. The reactions of these compounds with a variety of amines resulted in addition-rearrangement reactions with the formation of the corresponding methyl 2-substituted-5-substituted amino-1,6-dihydro-6-oxo-4-pyrimidine carboxylates.     

EDXD studies above 400 GPa (and prospects for obtaining pressures near 1 TPa and doing EDXD studies at such pressures)

Abstract

We have now taken two materials (W, Mo) to pressures greater than the pressure at the center of the earth for the first time, with all pressures based on x-ray diffraction and shock-based equations of state. The present paper describes x-ray diffraction studies of a sample in which pressure equals or exceeds 438 GPa. It is noted that as a result of the process of pressure strengthening, pressures of 1 TPa may be attainable.

Presented at the IUCr Workshop on ‘Synchrotron Radiation Instrumenration for HighPressure Crystallography’. Daresbury Laboratory 20-21 July 1991     

On tall cardinals and some related generalizations

We continue the study of tall cardinals and related notions begun by Hamkins in 2009 and answer three of his questions posed in that paper.     

Electron microscopy methods for space-, energy-, and time-resolved plasmonics

Nanoscale plasmonic systems combine the advantages of optical frequencies with those of small spatial scales, circumventing the limitations of conventional photonic systems by exploiting the strong field confinement of surface plasmons. As a result of this miniaturization to the nanoscale, electron microscopy techniques are the natural investigative methods of choice. Recent years have seen the development of a number of electron microscopy techniques that combine the use of electrons and photons to enable unprecedented views of surface plasmons in terms of combined spatial, energy, and time resolution. This review aims to provide a comparative survey of these different approaches from an experimental viewpoint by outlining their respective experimental domains of suitability and highlighting their complementary strengths and limitations as applied to plasmonics in particular.