共查询到20条相似文献,搜索用时 31 毫秒
1.
Zeper Abliz Junji Aoki Toyotoshi Ueda Teruo Kan Minoru Takekawa Satoshi Iwashima 《Journal of mass spectrometry : JMS》1993,28(5):607-614
Electron impact mass spectra were measured for five isomers of pyridinobenzanthrones and three isomers of benzobenzanthrones. The fragmentation pattern and intensity of M2+, [M – H]+, [M – CO]i+, [M – CO – H(or 2H)]i+ and [M – CO – HCN]i+ (i = 1, 2) ions indicated remarkable differences and very interesting features according to the isomers with or without nitrogen and condensation positions of a pyridino or benzo ring to the benzanthrone skeleton. Further, the competition of decompositions through [M – H]+, [M – CO]+˙ or [M – HCN]+˙ ions was confirmed by the observation of metastable ions and the appearance energies of fragment ions. Interesting observations from these results were expulsion of an H atom in close proximity to the area around an O?C group, a weak bonding interaction between sp2 C? H and an O?C group, inducing specific hydrogen rearrangement, and characteristic charge localization on heteroatoms. 相似文献
2.
John G. Stuart Michael J. Quast Gary E. Martin Vincent M. Lynch Stanley H. Simonsen Milton L. Lee Raymond N. Castle Jerry L. Dallas Boban K. John LeRoy F. Johnson 《Journal of heterocyclic chemistry》1986,23(4):1215-1234
Syntheses of benzo[3,4]phenanthro[1,2-b]thiophene, benzo[3,4]phenanthro[2,1-b]thiophene and their 1-methyl analogs are reported as potential constituents of solvent refined coal liquids and for mutagenicity testing. The attempted synthesis of the 13-methyl analogs which gave the 11-methyl isomers is also described. Total assignments of the 1H- and 13C-nmr spectra based on long range optimized heteronuclear protoncarbon two-dimensional chemical shift correlation are reported. Carbon assignments obtained for benzo[3,4]-phenanthro[1,2-b]thiophene using this approach were confirmed with a 125 MHz 13C–13C INADEQUATE spectrum. X-Ray crystal structures were determined for benzo[3,4]phenanthro[1,2-b]thiophene and 1-methyl-benzo[3,4]phenanthro[2,1-b]thiophene. Both molecules were helically distorted from planarity. Close intramolecular contacts between the bay region H1–H13 and ClMe-H13 of 2.03 and 2.28 Å, respectively, were responsible for the distortions. There were no close intermolecular contacts of <3.5Å. both molecules refined to an R value of <0.05. 相似文献
3.
Marvin L. Tedjamulia Yoshinori Tominaga Raymond N. Castle Milton L. Lee 《Journal of heterocyclic chemistry》1983,20(4):861-866
The synthesis of benzo[b]phenanthro[2, 3-d]thiophene ( 5 ), benzo[b]phenanthro[4, 3-d]thiophene ( 6 ), benzo-[b]phenanthro[2, 1-d]thiophene ( 9 ), benzo[b]phenanthro[3, 2-d]thiophene ( 14a ), anthra[1, 2-b]benzo[d]thiophene ( 24 ), anthra[2, 3-b]benzo[d]thiophene ( 29 ) and anthra[2, 1-b]benzo[d]thiophene ( 30 ) is described as well as the preparation of 13-methylbenzo[b]phenanthro[3, 2-d]thiophene ( 14b ). 相似文献
4.
The synthesis of benzo[b]phenanthro[1,2-d]thiphene ( 1 ), benzo[b]phenanthro[4,3-d]thiophene ( 2 ), benzo-[b]phenanthro[2,1-d]thiophene ( 3 ) and benzo[b]phenanthro[3,4-d]thiophene ( 4 ) from appropriately substituted olefines by photochemical cyclodehydrogenation is described. The photolysis of olefin 9 gave a mixture of 4 and anthra[1,2-b]benzo[d]thiophene ( 5 ). 相似文献
5.
Lyle W. Castle Milton D. Johnston Charalampos L. Camoutsis Raymond N. Castle 《Journal of heterocyclic chemistry》1992,29(7):1805-1815
The 1H nmr spectra of phenanthro[9′,10′:4,5]thieno[2,3-c]quinoline, benzo[f]phenanthro-[9′,10′:4,5]thieno[2,3-c]quinoline and benzo[h]phenanthro[9′,10′:4,5]thieno[2,3-c]quinoline are highly congested. For each compound, all protons abide in an aromatic environment complicated by pseudo-symmetric regions which result in multiple overlap of the different spin systems these molecules contain. We illustrate here the utility of the HMQC-TOCSY experiment to identify spin systems when the proton spectrum is highly congested. To complete the assignment of the 1H and 13C nmr spectra of each compound the HMBC experiment is used to assign the quaternary carbons. 相似文献
6.
Yoshinori Tominagaxs Lyle W. Castle Raymond N. Castle 《Journal of heterocyclic chemistry》1996,33(4):1017-1018
Photocyclization of the substituted 2-(naphth-1-yl)-3-(thien-2-yl)propenoic acid ( 3 ) in the presence of iodine and air in a benzene-cyclohexane mixture afforded a separable mixture of three compounds, phenanthro[2,1-b]thiophene-10-carboxylic acid ( 4 ), phenanthro[2,1-b]thiothene ( 5 ), and naphtho[1,8-cde]-thieno[3,2-g][2]benzopyran ( 6 ) 相似文献
7.
The synthesis of three novel polycyclic heterocyclic ring systems are reported via photocyclization. The specific final products in these ring systems are: phenanthro[9′,10′:4,5]thieno[2,3-c]quinoline ( 13 ), benzo[h]-phenanthro[9′,10′:4,5]thieno[2,3-c]quinoline ( 14 ), and benzo[f]phenanthro[9′,10′:4,5]thieno[2,3-c]quinoline ( 15 ). 相似文献
8.
The syntheses of the K-oxides and K-imine derivatives of benzo[b]phenanthro[2,3-d]thiophene and benzo-[b]phenanthro[3,2-d]thiophene are described. The parent hydrocarbons 1 and 2 were oxidized with osmium tetroxide and sodium metaperiodate, and the dialdehydes 12 and 18 so formed, cyclized to the corresponding epoxides 1a,12b-dihydrobenz[b]oxireno[9,10]phenanthro[2,3-d]thiophene ( 7 ) and 1a,12b-dihydrobenz-[b]oxireno[9,10]phenanthro[3,2-d]thiophene ( 13 ). Reaction of the oxiranes with sodium azide gave mixtures of azido-alcohols that, in turn, were transformed to the thiaarene imines 1a,12b-dihydro-1H-benz[b]azirino-[9,10]phenanthro[2,3-d]thiophene ( 8 ) and 1a,12b-dihydro-1H-benz[b]azirino[9,10]phenanthro[3,2-d]thiophene ( 14 ), respectively, with the aid of tri-n-butylphosphine. 相似文献
9.
A phenanthrene-fused cyclooctatetraene, namely benzo[a]phenanthro[9,10-e]cyclooctene has been synthesized by employing the “Reich-Paquette” procedure. 相似文献
10.
Masatomo Iwao Milton L. Lee Raymond N. Castle 《Journal of heterocyclic chemistry》1980,17(6):1259-1264
All isomers of the parent phenanthro[b]thiophenes, namely, phenanthro[1,2-b]thiophene, phenanthro-[2,1-b]thiophene, phenanthro[2,3-b]thiophene, phenanthro[3,4-b]thiophene, phenanthro[3,4-b]thiophene, phenanthro[4,3-b]thiophene and phenanthro[9,10-b]thiophene have been synthesized. 相似文献
11.
Hirotaka Kudo Marvin L. Tedjamulia Raymond N. Castle Milton L. Lee 《Journal of heterocyclic chemistry》1984,21(6):1833-1839
The synthesis of phenanthro[1,2-c]dibenzothiophene (6) , phenanthro[4,3-c]dibenzothiophene (10) , phenanthro[2,1-a]dibenzothiophene (14) , phenanthro[3,4-a]dibenzothiophene (16) , phenanthro[1,2-a]dibenzothiophene (19) , phenanthro[2,1-b]dibenzothiophene (20) , 8-methylphenanthro[3,2-a]dibenzothiophene (24) , 7-methylphenanthro[1,2-a]dibenzothiophene (25) , phenanthro[3,4-a]dibenzothiophene (27) , phenanthro[4,3-a]-dibenzothiophene (28) , 6-methylphenanthro[2,3-a]dibenzothiophene (31) , and 5-methylphenanthro[4,3-a]dibenzothiophene (32) is described. 相似文献
12.
Esa Mki Kalevi Pihlaja Imre Huber Ferenc Fülp Gbor Bernth Pirjo Vainiotalo 《Journal of mass spectrometry : JMS》1993,28(1):18-22
The electron impact ionization mass spectra of dipyrido [1,2-a:4,3-d]pyrimidinones are strongly influenced by the degree of aromaticity of the fused rings. The molecular ions of the compounds are fairly stable. The main routes of fragmentation involve formation of the [M – H]+ ion and loss of substituents, H2CN˙, CO and alkyl radicals. 相似文献
13.
Thomas Hellman Morton 《Journal of mass spectrometry : JMS》1991,26(1):18-23
An ion–neutral complex is a non-covalently bonded aggregate of an ion with one or more neutral molecules in which at least one of the partners rotates freely (or nearly so) in all directions. A density-of-states model is described, which calculates the proportion of ion–neutral complex formation that ought to accompany simple bond cleavages of molecular ions. Application of this model to the published mass spectrum of acetamide predicts the occurrence of ions that have not hitherto been reported. Relative intensities on the order of 0.1 (where the abundance of the most intense fragment ion = 1) ere predicted for [M – HO]+ and [M – CH4]+˙ ions, which have the same nominal masses as the prominent [M – NH3]+˙ and [M – NH2]+ fragments. High-resolution mass spectrometric experiments confirm the presence of the predicted fragment ions. The [M – HO]+ and [M – CH4]+˙ fragments were observed with relative abundances of 0.02 and 0.04, respectively. Differences between theory and experiment may be ascribed to effects of competing distonic ion pathways. 相似文献
14.
Marina Rentzea Gsta Rimmler Franz A. Neugebauer 《Journal of mass spectrometry : JMS》1993,28(5):494-498
Not only strongly basic aromatic amines such as ‘proton sponges’ show characteristic [M – Me2NH – H]+ peaks corresponding to cyclization to stable heterocyclic ions under electron impact. The fragmentation of the title compounds, which are weak bases, leads to [M – RNH2 – C6H5]+ heteroaromatic ions. These are the 7-phenyl-7H-benz[kl]acridine radical cation and the delocalized stable 7H-benz[kl]acridin-7-ylium ion as shown by unimolecular metastable ion spectra, collision-induced decomposition (CID) tandem mass spectrometry (MS/MS) and accurate mass measurements. The high-collision-energy CID tandem mass spectra of these ions are perfectly superimposable on those of the ions produced by the reference substance, 7-phenyl-7H-benz[kl]acridine obtained as a by-product in the Ullmann phenylation of 1,8-diaminonaphthalene. This combination of MS/MS experiments also provides strong support for the gas-phase reaction mechanism leading to the benz[kl]acridine ions and for the structures of these ions. 相似文献
15.
J. A. Rowley 《Journal of mass spectrometry : JMS》1989,24(11):997-1000
The positive electron impact (EI) and isobutane chemical ionization (CI) mass spectra of six nitramine nitrates were studied with the aid of some accurate mass measurements. In the EI spectra, β fission relative to both the nitramine and nitrate ester is important. In the CI spectra a major ion occurs at [MH – 45]+ and was found to be mainly due to [M + 2H ? NO2]+. All of the compounds except N-(2 hydroxyethyl)-N-(2′,4′,6′-trinitrophenyl)nitramine nitrate gave an [MH]+ ion. The [MH – 45]+ ion in the isobutane CI mass spectra of tetryl is also due to [M + 2H ? NO2]+. 相似文献
16.
Lyle W. Castle Milton D. Johnston Charalampos L. Camoutsis Raymond N. Castle 《Journal of heterocyclic chemistry》1992,29(7):1869-1871
The pseudo-symmetric structure of benzo[f]phenanthro[9′,10′:4,5]thieno[2,3-c]quinoline causes overlap of the resonances corresponding to H1 and H15 and also those of H11 and H12. We report here the observation of nOe between these pseudo-equivalent protons using the HMQC-NOESY experiment acquired without decoupling during acquisition. 相似文献
17.
M. J. Musmar Gary E. Martin Marvin L. Tedjamulia Hirotaka Kudo Raymond N. Castle Milton L. Lee 《Journal of heterocyclic chemistry》1984,21(3):929-933
Application of autocorrelated homonuclear (COSY) and proton-carbon chemical shift correlation two-dimensional nmr experiments to the problem of assigning the 1H- and 13C-nmr spectra of phenanthro[4,3-a]dibenzothiophene fails despite their considerable utility in the assignment of the spectra of the smaller phenanthro[b]thiophenes. The failure of these techniques in the case of phenanthro[4,3-a]dibenzothiophene is predominantly due to the inability of the COSY spectrum to provide the means of subgrouping the proton resonances into their component spin subsystems. Two-dimensional relayed coherence transfer nmr experiments which first established coherence between vicinally coupled protons which is then transferred to the carbon spins which are ultimately observed circumvent these problems. The application of two-dimensional relayed coherence transfer to phenanthro[4,3-a]dibenzothiophene is described, the technique leading to the sub-grouping of all five of the proton spin subsystems and thus providing a means of beginning the total assignment. 相似文献
18.
The fragmentations of [(CH3)2SiO]n, (Dn), where n = 4, 5, 6, 7, 8, 9, 10, 12 and 15 are reported. The behaviour of these compounds under electron-impact is governed by the size of the siloxane ring. Rings smaller than D6 have base peaks corresponding to [M – 15]+ ions; larger rings all show base peaks of m/e 73 [Si(CH3)3]+. A transannular mechanism previously applied only to D5 and D6 is extended and modified to account for the behaviour of larger rings. A ring con-traction mechanism is proposed which leads to the formation of smaller rings and doubly charged ions. A new transannular mechanism is proposed to account for the production of [M – 177]+ and [M – 193]+ ions. 相似文献
19.
J. H. Beynon R. M. Caprioli R. G. Cooks N. M. M. Nibbering T. A. Molenaar-Langeveld 《Journal of mass spectrometry : JMS》1975,10(10):824-830
The metastable ions [M]2+, [M – H]2+· and [M – H2]2+ from malononitrile fragment by loss of [CH]+, [C]+· and [C]+·, respectively. The reaction of the molecular ion involves the methylene and nitrile carbon atoms in the statistical probability ratio, while that of [M – H]2+· involves exclusively the nitrile carbon and that of [M ? H2]2+ involves an approximately equal contribution, from both sources. It is suggested that the metastable molecular ion fragments through a bipyrimidal intermediate. 相似文献
20.
The CA spectra of the [M – Alkene]+·- and [M – Alkyl]+- ions from several 2-alkoxy-benzoic acid methyl esters and two 2H labelled 2-ethoxybenzoic acid methyl esters are discussed. The results show that the [M – alkene]+· ions decomposing after 10?5 s by collisional activation have the structure of the ionised salicylic acid methyl ester. Moreover, it is demonstrated that the [M – methyl]+ ions from the 2-ethoxy esters exist in two different structures. No equilibration between these two structures is observed even after 10?5s. Structures for several daughter ions generated by collisional activation are discussed using the CA spectra of the labelled compounds. 相似文献