Mass spectral fragmentation pattern of 2,2′-bipyridyls. Part XIII. 6-Chloro- and 6-bromo-2,2′-bipyridyls

The mass spectra of 6-chloro- and 6-bromo-2,2′-bipyridyls are reported. The principal fragmentation route from the molecular ions involves loss of the halogen group to give the M-1 ion of 2,2′-bipyridyl which gives rise to the base peak in the spectra. Loss of HCN before loss of Cl occurs to a small extent with 6-chloro-2,2′-bipyridyl.     

Umsetzung von Metall- und Metalloidverbindungen mit mehrfunktionellen Molekülen,XIX. Synthese von Amidoborazinen

Reaction of Metal and Metalloid Compounds with Polyfunctional Molecules. XIX. Synthesis of Amidoborazines By reaction of 2-chloro-1,3,4,5,6-pentamethylborazin with silylated carbonic acid amides and thioamides resp. the corresponding amidoborazines are obtained. By reaction of lithiated hexamethyldisilazane with 2-chloro-1,3,4,5,6-pentamethylborazine, the 2-hexamethyldisilazanyl-1,3,4,5,6-pentamethylborazine is formed. ¹H, ¹¹B, and ¹⁹F n.m.r. spectra, mass spectra and characteristic i.r. group frequencies are reported.     

The m/z 91 rearrangement ion in the mass spectra of some 1,4-benzodiazepines

With the aid of isotope labeling and by substituent shifts, the relatively strong m/z 91 ion in the mass spectra of 7-chloro-2-methoxy-5-phenyl-3H-1,4-benzodiazepine and related compounds was shown to contain the 5-phenyl ring and the 3-CH₂ group. Mechanisms involving the opening of the 7-membered ring and the migration of the phenyl ring from C-5 to C-3 are postulated for the formation of this ion. This rearrangement ion was also observed in the mass spectra of some 1-alkyl-7-chloro-1,3-dhydro-5-phenyl-2H-1,4-benzodiazepin-2-ones.     

Mass spectra of some 3-substituted benzo[b]quinuclidines III

The mass spectra of 3-methoxycarbonyl-, 3-ethoxycarbonyl-, 3-(2-dimethylaminoethoxy)carbonyl-, 3-amino-, 3-hydroxymethyl-, 3-chloro-3-methoxycarbonyl-, 3-chloro-3-ethoxycarbonyl-, and 3-chloro-3-cyano-substituted benzo[b]quinuclidines were investigated. The fragmentation of these compounds under electron impact through the open form of the molecular ion is discussed.See [1] for communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 825–832, June, 1972.     

Synthesis,characterization and antibacterial activity of 1-([6-bromo-2-hydroxy-naphthalen-1-yl]arylphenyl)methyl)-3-chloro-4-(arylphenyl)-azetidin-2-one

One-pot synthesis of 1-([6-bromo-2-hydroxy-naphthalen-1-yl]-aryl-phenyl)methyl)-3-chloro-4-(aryl-phenyl)azetidin-2-ones has been reported in the present research work via Staudinger [2 + 2] ketene-imine cycloaddition reaction pathway. The reaction of 1-((Benzylideneamino)(aryl)methyl)-6-bromo-naphthalen-2-ols with chloroacetic acid and triethylamine afforded 1-([6-bromo-2-hydroxynaphthalen-1-yl]aryl-phenyl)methyl)-3-chloro-4-(aryl-phenyl)azetidin-2-ones. For the structural elucidation of series of compounds, different analytical and spectroscopic techniques such as elemental analysis, IR spectra, ¹H-NMR spectra and mass spectra were used. All the newly synthesized compounds were tested for their anti-bacterial activity studies. It revealed that some of the compounds possesses moderate to good activities as compared to standard drugs. The widest spectrum of anti-bacterial activities against both gram-positive and gram-negative bacterial strains among the examined compounds possessed having more hydroxyl group along with β-lactam ring compared to other substituted azetidinones.     

Photodissociation and collision-induced dissociation of molecular ions from methylphenol and chloromethylphenol

The photodissociation of molecular ions from a series of methylphenols and chloromethylphenols was studied using Fourier transform ion cyclotron resonance mass spectrometry (FTMS). The photodissociation spectra contain both UV and visible absorption maxima. The positions of these bands correlate well with solution electronic absorption spectra and photoelectron spectra, respectively, suggesting that photodissociating populations of the molecular ions have not rearranged. The molecular ion of benzyl alcohol can be readily distinguished from the isomeric 2- and 4-methylphenol ions on the basis of the position and intensity of the photodissociation bands, and the identity of the photoproduct. The p-chlorophenol isomers, 4-chloro-2-methylphenol and 4-chloro-3-methylphenol, cannot be distinguished by their photodissociation spectra. Minor differences exist between these spectra and that of the o-chlorophenol isomer 2-chloro-5-methylphenol, suggesting that the relative positions of the chloro and hydroxy groups may have a greater effect on photodissociation than the position of the methyl group. For comparison, low-energy collision-induced dissociation using FTMS was also performed on the same ions.     

Mannich's arsindole (1,3-dichloro-2-diethylaminomethylbenzo[b]arsole hydrochloride). Ultraviolet spectrum and behaviour on electron impact. A comparison with other heterocyclic and acyclic chloroarsines

The ultraviolet and mass spectra of the title compound have been recorded and compared with those of 2-chloro-2-phenylvinyldichloroarsine (and other chloroarsines). The spectra of the arsindole resemble those of related indoles, phosphindoles and other aromatic heterocyclic systems, and are markedly different from those of the above acyclic chloroarsine, indicating the probable involvement of arsenic in a cyclic π-delocalised system.     

Conversion of 2-acetamido-1-thiochromone to the corresponding 4-chloro and 4-amino derivatives

2-Acetimido-4-chloro-2H-1-thiochromene, in which the chlorine atom is exchanged by hydroxy and amino groups, was synthesized by the action of phosphorus oxychloride on 2-acetamido-1-thiochromone. It was established on the basis of the IR, UV, PMR, and mass spectra that the product of the reaction of this compound with aniline has the 2-acetaraido-1-thiochromene structure.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 622–625, May, 1978.     

A convenient synthesis of 2-amino-4H-1,3,4-oxadiazino[5,6-b]-quinoxaline derivatives

The reaction of 6-chloro-2-(1-methylhydrazino)quinoxaline 4-oxide 5 with a 2-fold molar amount of ethyl chloroglyoxalate gave ethyl 8-chloro-4-methyl-4H-1,3,4-oxadiazino[5,6-b]quinoxaline-2-carboxylate 6 , whose reaction with hydrazine hydrate afforded the C₂-hydrazinocarbonyl derivative 7 . The reaction of compound 7 with nitrous acid provided the C₂-acylazide derivative 8 , which was converted into the C₂-amino 9 , C₂-carbamate 11a-c, 12a,b , and C₂-ureido 13a-c, 14 derivatives. The mass spectral fragmentation patterns were examined for compounds 10–14 , wherein the molecular ion peak did not appear in the mass spectra of compounds 10c, 11a-c, 12a,b, 13c , and 14.     

4-Hydroxy-2-quinolones 141. Synthesis and structure of 5R-3-hydroxy-1,5-dihydropyrazolo[4,3-<Emphasis Type="Italic">c</Emphasis>]quinolin-4-ones

Treatment of 1R-4-chloro-3-ethoxycarbonyl-2-oxo-1,2-dihydroquinolines with p-toluenesulfonylhydrazide in refluxing ethanol and in the presence of triethylamine gives the 3-hydroxy-5R-1,5-dihydropyrazolo[4,3-c]quinolin-4-ones. The possible mechanism of formation, features of the steric structure of the synthesized compounds, and their NMR and mass spectra are discussed. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 233–238, February, 2008.     

Vibrational analysis of tertiary alkyl chlorides

Vibrational spectra were obtained for 2-chloro-2-methylpentane, 3-chloro-3-methylpentane, 2-chloro-2-methylhexane, and 3-chloro-3-methylhexane. All four compounds exist in T_HHH and T_CHH conformations in the neat liquid, and the T_HHH' conformer of the last named compound also seems to be present. Only the T_HHH conformer is present in the crystalline state of the two pentanes, but the hexanes could not be made to crystallize and both conformers were present in the solid. A 44-parameter modified valence force field was used in normal coordinate calculations, with fifteen force constants being adjusted to fit 188 assigned frequencies below 1500 cm^?1 of six molecules (two conformers each of 2-chloro-2-methylbutane, 2-chloro-2-methylpentane, and 3-chloro-3-methylpentane). The resulting force constant values were used in zero-order calculations of the two hexanes as an aid in interpreting vibrational spectra for those compounds.     

The synthesis of the benzyltetrahydropyrans

The 2-benzyl-, 3-benzyl- and 4-benzyltetrahydropyrans have been prepared via the reaction of benzylsodium with 2-chloro-, 3-bromo- and 4-chlorotetrahydropyran in 49, 29 and 27% yields, respectively. The structures of these compounds were substantiated from their nmr, mass spectra and analytical data.     

STUDIES IN THE HETEROCYCLIC COMPOUNDS V1. SOME REACTIONS OF 5-CHLORO-2-THIOPHENESULFONYL DERIVATIVES

Abstract

The reactions of 5-chloro-2-thiophenesulfonyl chloride are described. Treatment of the sulfonyl chloride with ammonia, hydrazine hydrate, sodium azide, indole and imidazole gave the sulfonamides (5), sulfonohydrazide (4), sulfonyl azide (3), 1-(5-chloro-2-thiophenesulfonyl)indole (27) and 1-(5-chloro-2-thiophenesulfonyl)-imidazole (26), respectively. The sulfonyl chloride was reacted further with 20 aryl-and cycloalkyl-amines to give the corresponding sulfonamides (6)-(25). Attempted chlorination of the sulfonyl chloride (2) with sulfuryl chloride or bromination of the sulfonyl azide (3) with pyridinium bromide perbromide failed. However, nitration of the sulfonyl chloride (2) with fuming nitric acid gave the 4-nitro-sulfonyl chloride (28), which with sodium azide afforded the 5-chloro-4-nitro-sulfonyl azide (29). The sulfonyl azides, (3) and (29), have been reacted with triphenylphosphine, triethylphosphite, norbornene and cyclohexene. The azides reacted further with indole and 1-methylindole to give the 2-sulfonyl-iminoindolines (34)-(36). The infra-red spectra and mass spectra of some of the substituted thiophenesulfonyl derivatives are discussed.     

Differentiation of estriol glucuronide isomers by chemical derivatization and electrospray tandem mass spectrometry

This paper describes a way of differentiating between the three isomers of estriol glucuronide by the use of chemical derivatization and liquid chromatography/electrospray tandem mass spectrometry (MS/MS). In their native form, these isomers gave rise to almost identical product ion spectra, involving the neutral loss of 176 Da (i.e. monodehydrated glucuronic acid), which made it impossible to determine the position of conjugation by MS/MS alone. In order to change the fragmentation pathways, positive charges were introduced into the analytes by chemical derivatization. The following reagents were tested: 2-chloro-1-methylpyridinium iodide, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 2-picolylamine. Interestingly, derivatization using a combination of all three reagents gave a selective fragmentation pattern that could differentiate between the isomers estriol-16-glucuronide and estriol-17-glucuronide. Estriol-3-glucuronide, which lacks a free phenolic group, could be differentiated through a different type of reaction product when exposed to 2-chloro-1-methylpyridinium iodide. Furthermore, in order to assist structural assignment of the fragments, their accurate masses were determined using a hybrid quadrupole time-of-flight mass spectrometer and fragmentation pathways were elucidated by the use of MS3 on an ion trap mass spectrometer.     

Heterocyclic Compounds with a Bridge Nitrogen Atom. 14. Cycloaddition of Acetylenedicarboxylic Acid Ester to 2-Chloro-N-phenacylpyridinium Ylide. Crystal Structure of Dimethyl Ester of 5-Chloro-3-(p-nitrobenzoyl)indolizine-1,2-dicarboxylic Acid

Derivative of 5-chloroindolizine is formed in the reaction of 2-chloro-1-(p-nitrophenacyl)pyridinium ylide with acetylenedicarboxylic acid dimethyl ester, the structure of which was demonstrated by X-ray diffraction analysis. According to data of ¹H NMR and mass spectra indolizine obtained undergoes an unusual intramolecular cyclization with the formation of benz[e]cycl[3.3.2]azine nucleus.     

Vibrational spectra of 1-chloro-2-methylpropane and 1-chloro-2,2-dimethylpropane

Infrared and Raman spectra are obtained for 1-chloro-2-methylpropane and 1-chloro-2,2-dimethylpropane. The former compound exists as a mixture of P_C and P_H' conformers in the liquid and unannealed solid states, but only the P_C conformer is present in the crystalline solid. Vibrational assignments are made for both conformers of 1-chloro-2-methylpropane and for 1-chloro-2,2-dimethylpropane with the aid of normal coordinate calculations.     

Spectrométrie de Masse d'Hétérocycles Azotés. X–Contribution à l'Etude du Comportement de ll'Ion Aniline et des Ions Aminopyridines avant Fragmentation par Perte de HCN

The study of the mass analysed ion kinetic energy spectra of deuterated derivatives of aniline, aminopyridines and 2-chloro-5-aminopyridine shows that prior to HCN loss, hydrogen scrambling does not occur for aminopyridines and is limited but noticeable for aniline. In the case of this last compound the extent of scrambling varies markedly for small variations in the energy of the ions studied, these variations being within the energy window corresponding to metastable ions. Furthermore, an examination of the mass analysed ion kinetic energy spectra of monodeuterated derivatives of aminopyridines leads to the rejection of the generally accepted mechanism for HCN loss from the molecular ions of these compounds.     

Stereochimie d'heterocycles du groupe IVB—I : Syntheses stereoselectives d'alcoxy-1 et d'amino-1 sila-1 cyclobutanes

Stereoselective synthéses (60 to 90%) of some silacyclobutanes were performed by alcoholysis or aminolysis of 2 (or 3)-methyl-1-chloro-1-silacyclobutanes. Relative configurations of 2 (or 3)- methyl-1-alkoxy (or 1-amino)-1-silacyclobutanes thus prepared have been assigned from their NMR spectra. The mechanism of these stereoselective reactions, based on the rapid stereomutation of 1-chloro-1-silacyclobutanes, is discussed.     

A NOVEL SERIES OF PALLADIUM(II) AND PLATINUM(II) COMPLEXES WITH 1,4-BENZODIAZEPINES AS LIGANDS

Abstract

The complexing behaviour towards palladium(II) and platinum(II) halides of some 1,4-benzodiazepines is reported. The ligands used in this study are 7-chloro-2-methylamino-5-phenyl-3H-1,4-benzodiazepin-4-oxide, 1,3-dihydro-7-nitro-5-phenyl-2H-1,4-benzodiazepin-2-one and 7-chloro-1-methyl-5-phenyl-3H-1,4-benzodiazepin-2-one. The complexes have been studied by means of magnetic susceptibility measurements, infrared and far infrared spectra, electronic spectra and conductivity measurements. The most convincing structural evidence for these complexes is a square planar stereochemistry with bridging ligands joining two metal ions and terminal halides in the 1:1 complexes and terminal ligands and terminal halides in the 1:2 derivatives. Assignments for the metal-ligand and metal-halide bands have also been made.     

Chiroptical properties of (R)-3-chloro-1-butene and (R)-2-chlorobutane

Coupled cluster and density functional models of specific rotation and vacuum UV (VUV) absorption and circular dichroism spectra are reported for the conformationally flexible molecules (R)-3-chloro-1-butene and (R)-2-chlorobutane. Coupled cluster length- and modified-velocity-gauge representations of the Rosenfeld optical activity tensor yield significantly different specific rotations for (R)-3-chloro-1-butene, with the latter providing much closer comparison (within 3%) to the available gas-phase experimental data at 355 and 633 nm. Density functional theory overestimates the experimental rotations for (R)-3-chloro-1-butene by approximately 80%. For (R)-2-chlorobutane, on the other hand, all three models give reasonable comparison to experiment. The theoretical specific rotations of the individual conformers of (R)-3-chloro-1-butene are much larger than those of (R)-2-chlorobutane, in disagreement with previous studies of the temperature dependence of the experimental rotations in solution. Simulations of VUV absorption and circular dichroism spectra reveal large differences between the coupled cluster and density functional excitation energies and the rotational strengths. However, while these differences lead to very different specific rotations for (R)-3-chloro-1-butene, they have much less impact on the computed specific rotations for (R)-2-chlorobutane. In addition, the coupled cluster VUV absorption spectrum of (R)-2-chlorobutane compares well to experiment.