摘要:

The fragmentation of 3,6-dibenzyl, 2,5-diketo piperazine in the mass spectrometry is presented. The general mechanism is proposed and discussed.

ISSN:0008-4042    

DOI:10.1139/v71-259

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The reactivity of a series of 14 aliphatic ketones in the crossed aldol condensation with chloral has been studied in glacial acetic acid and in dimethoxyethane. The reaction is irreversible and not accompanied by dehydration of the resulting 1,1,1-trichloro-3-hydroxy-4-alkanones. Except for butanone, condensation occurs preferentially at the least-hindered position of an unsymmetrical ketone. The α-methyl/α-methylene condensation product ratio obtained from ketones of the general formula RCH2COCH3is higher in acetic acid than in dimethoxyethane as solvent when sodium acetate is used as catalyst. The steric size and chain length of the alkyl groups of methyl alkyl ketones have a marked effect on the reactivity of the α-methyl group toward chloral. Condensation at the α-methylene group results in the formation of diastereomeric ketols which epimerize under the preparative reaction conditions.

ISSN:0008-4042    

DOI:10.1139/v71-260

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

A number of acyclic acyl alkyl diimides have been obtained by oxidation of the corresponding alkyl hydrazides. A new method for the synthesis of α-cyanoalkyl hydrazides, the reaction of acid hydrazides with ketones in the presence of sodium cyanide, has been explored. All the acyl alkyl diimides so obtained exhibit a medium to weak i.r. band atca. 1550 cm−1; evidence supporting the assignment of this band to the —N=N— stretch is given. The results of oxidation of 5-methyl and 5-phenyl-pyrazolidin-3-one are reported, together with the synthesis and oxidation of tetrahydro-6-methyl-3(2H)-pyridazinone.

ISSN:0008-4042    

DOI:10.1139/v71-261

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The difficulties which in the past have precluded the preparation of some synthetically potentially useful ethylenedioxy-tetrahydronaphthalenone and -dihydroindanone derivatives have been overcome. The proclivity of the tetrahydronaphthalenone compounds to undergo acid- and base-catalyzed rearrangements has been shown to be paralleled to some extent by the analogous dihydroindanone compounds.

ISSN:0008-4042    

DOI:10.1139/v71-262

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Reaction of 1-nitroso-2-naphthylamine with a series of 3-aroylaziridines affords (a) 3-arylbenzo[f]-quinoxalines, (b) cyclohexylimino derivatives of 2-aroylnaphtho[1,2-d]imidazoles, and (c) a 2-arylnaphtho[1,2-d]imidazole. Electron-withdrawing substituents in either the2or3aryl moieties of the aziridine lead to preferential formation of products of typeawhereas electron-donating substituents in either of these positions result in the formation of products of typeb. The results of deuterium labelling and unambiguous synthetic studies in support of the proposed 1,3-dipolar cycloaddition mechanism are discussed.

ISSN:0008-4042    

DOI:10.1139/v71-263

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Photolysis of diphenylsilacyclohexanone in diethyl fumarate yields a product shown to be the cyclopropane resulting from trapping of a siloxycarbene by the alkene.

ISSN:0008-4042    

DOI:10.1139/v71-264

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Siloxycarbenes, formed by the photolysis of dimethyl- or diphenylsilacyclohexanone have been trapped as oxiranes or as the ring-opened hydrolysis products of oxiranes, with simple aldehydes and ketones such as acetaldehyde, or cyclohexanone. The reactions are interpreted as arising from the nucleophilic attack of the siloxycarbene on the carbonyl group. The structures of the oxiranes and their hydrolysis products have been established.

ISSN:0008-4042    

DOI:10.1139/v71-265

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Magnesium orthovanadate crystallizes in the orthorhombic space groupCmcawitha = 6.053(3),b = 11.442(6),c = 8.330(3) Å, andZ = 4. The structure was refined by full matrix least square methods to a finalRvalue of 0.047 using 1697 reflections measured by a quarter circle General Electric automatic diffractometer. The structure was assumed to be isomorphous with that of Ni3(VO4)2, reported by Durif and Bertaut (2), and the refinement started using the same fractional atomic coordinates. The structure consists of nearly cubic closest packing of oxygen atom layers roughly normal to thedirection with the Mg ions in two types of octahedral sites and the V ion in a tetrahedral site. The VO4group has a crystallographic mirror plane. The cations lying on sites ofCmsymmetry show an average Mg—O bond length of 2.092 Å, compared to 2.098 Å for cations lying at sites ofC2hsymmetry. The anion deviates significantly and substantially from regularity with the three oxygen atoms shared with only two cations showing V—O bond lengths within 0.015 Å of their mean, 1.70 Å, whereas the remaining oxygen atom, which is shared with three Mg ions, lies 1.809 Å from the V ion. The structure has characteristics similar to those of spinel.

ISSN:0008-4042    

DOI:10.1139/v71-266

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The configuration of certain substituted hexahydrocarbazoles2, of significance in connection with earlier work, has been established. A study of the temperature dependence of the n.m.r. spectra ofN-acetyl derivatives, initiated with the intention of distinguishing betweencis- andtrans-fused isomers, has led to the conclusion that the distinction could not be made on this basis since all of the temperature-dependent phenomena, even in cases where thecis-fusion had been established by other means, could be associated with rotational isomerism of theN-acetyl group and no observable effects in the temperature range studied could be related to conformational mobility of the ring system. Nevertheless, the results obtained provide information of value and interest regarding the stereochemistry of hexahydrocarbazoles.

ISSN:0008-4042    

DOI:10.1139/v71-267

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The effect of pressure on the rates of aquation of Cr(NCS)63−and Cr(NH3)2(NCS)4− has been studied over the pressure range 1 to 2043 atm, at 50ˆC. The activation volumes for these reactions are found to be 16 ± 2 and −2.4 ± 0.8 ml/mol, respectively. The pressure dependence of the activation volumes, (∂ΔV*/∂P)T, are 15 ± 5 and 0 ± 1 ml/katm mol, respectively. These results are consistent with a dissociative interchange (Id) process for the aquation of Cr(NCS)63−and an SN2 front-side process for the aquation of Cr(NH3)2(NCS)4−.

ISSN:0008-4042    

DOI:10.1139/v71-268

出版商:NRC Research Press    

年代:1971

数据来源: NRC