Fragmentation of 1,4,5,8-tetraazaphenanthrenes upon electron impact: A new example of structural integrity of gas phase heteroaromatic cations

1,4,5,8-Tetraazaphenanthrene and some derivatives have been studied by mass and ion kinetic energy spectrometries. Deuterium labelling experiments show an unexpected structural integrity of the gas phase molecular ions which eliminate H(D)CN, even near threshold energies (field-free region reactions). The loss of N(1(8)) predominates largely over the loss of N(4(5)); the consecutive losses of H(D)CN are also highly specific. A similar specificty is observed for the chlorinated and methylated isomers. The atoms of the homocycle are not involved in the first steps of the fragmentation as indicated by the behaviour of 9-chloro-and 9-methyl-tetraazaphenanthrenes.     

新型1,4,5,8-萘酰亚胺类衍生物的合成

以1,4,5,8-萘四甲酸二酐(1)和2-乙基己胺(2)为原料,设计并合成了3种新型的1,4,5,8-萘酰亚胺类衍生物,其结构经1H NMR,IR和MS表征。中间体N-(2-乙基己基)-萘-1,8-二甲酸单酐-4,5-单甲酰亚胺的最佳反应条件为:19.7 mmol,n(1)∶n(2)=1.1∶1.0,以醋酸锌为催化剂,在DMF(20 mL)中于140℃反应15h,收率25%。     

Synthesis of 1,4,5,8-tetramethyl-2,3-diethoxycarbonylporphyrin

The synthesis of 1,4,5,8-tetramethyl-2,3-diethoxycarbonylporphyrin from the dihydrobromide of 1,3,7,13,17,19-hexamethyl-8,12-diethoxycarbonylbiladiene is described.     

Synthesis and structure of 1,4,5,8-tetraethynylnaphthalene derivatives

1,4,5,8-Tetraethynylnaphthalene derivatives 4a-c were synthesized for the first time. X-ray crystallographic structure analysis of 4a revealed three different modes of distortion, expanding of the substituents, twisting of the naphthalene skeleton and bending of the acetylene units, to reduce steric repulsion.     

Synthesis of 1-substituted-6-methyluracils

A series of 6-methyl-1H-pyrimidin-2,4-diones bearing different substituents in the 1-position of the uracil ring were prepared starting from substituted ureas and diketene.     

Trans-1,4,5,8-tetracarboethoxy- and 1,4,5,8-tetramethyl- 1,4,5,8-tetraazadecalin (tad)

Chemical correlation between the title compounds ($\text{7}$ and $\text{8}$) was performed. X-ray crystallographic analysis of the novel tetraurethane ($\text{7}$) proved the $\text{trans}$ configuration of ($\text{7}$) and indirectly that of tetramethyl TAD ($\text{8}$). The latter's chemical and conformational behavior is examined and discussed.     

Synthesis of 3-substituted-1-methylpyrazoles

Reaction of 3-bromo-1-methylpyrazole 1 with t-butyllithium at ? 100° followed by quenching of the lithiopyrazole intermediate allows regiospecific introduction of substituents into the 3-position of the 1-methylpyrazole ring.     

7-取代-8-羟基喹啉的合成

由2-氯辛烷与8-羟基喹啉钠反应制得7-(1′-甲基庚基)-8-羟基喹啉.用长碳链脂肪醛在碱性介质中与8-羟基喹啉反应,合成了一系列7-烯基-8-羟基喹啉(1);对不同结构长碳链脂肪醛合成作了研究.     

Synthesis of 1-substituted-7-hydroxyquinolinium salts

The reaction of 7-acetoxyquinoline with trifluorosulfonate esters of primary alcohols in methylene chloride or acetonitrile, followed by acid hydrolysis, provides a general synthesis of 1-substituted-7-hydroxyquinolines, whose phenolate anions are fluorescent.     

Molecular dynamics simulations of trans-1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin-based polymer-bonded explosives

Molecular dynamics has been applied to investigate the low-sensitivity explosive TNAD (trans-1,4,5,8-tetranitro-1,4,5,8-tetraazadecalin)-based polymer-bonded explosives (PBXs) with four typical fluorine polymers, PVDF (polyvinylidenedifluoride), PCTFE (polychlorotrifluoroethylene), F(2311) (fluorine rubber), and F(2314) (fluorine resin). The elastic constants, mechanical properties (tensile modulus, bulk modulus, shear modulus, and Poission ratio), binding energies, and detonation performances are first reported for the TNAD-based PBXs. The results show that the mechanical properties of TNAD can be effectively improved by the addition of small amounts of fluorine polymers, and the overall effect of fluorine polymers on the mechanical properties of the PBXs along three crystalline surfaces is (001) > (010) > (100). On each crystal surface, improvement in the ductibility made by the fluorine polymers changes approximately in the sequence of PVDF > F(2311) > F(2314) > PCTFE. The binding energies between different TNAD crystalline surfaces and different polymer binders with the same chain segment or mass fraction both decrease in the order of (010) > (100) > (001). The binding properties of the polymers with the same chain segment on each crystal surface of TNAD increase as PVDF < F(2311) < F(2314) < PCTFE, while those of different polymers in the same content decrease in the sequence of PVDF > F(2311) > F(2314) > PCTFE. The detonation performances of the PBXs decrease in comparison with the pure crystal, but they are superior to those of TNT.     

Synthesis of 1-substituted-3,3-dimethyl-3,4-dihydroisoquinolines

The Ritter reaction between -substituted propionitriles and dimethylbenzylcarbinols gives 3,3-dimethyl-3,4-dihydroisoquinolines containing substituents in the 1-position corresponding to those in the starting nitrile.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 657–659, May, 1991.     

Synthesis of 3-glycosyl-5-substituted-2-isoxazolines

The synthesis of eight 3-glycosyl-5-substituted-2-isoxazolines is described. They are obtained by 1,3-dipolar cycloaddition from some 2-deoxy-sugar oximes. A side product was isolated. The physical and spectroscopycal characterization of all compounds are reported.     

三嗪树枝状1,4,5,8-萘酰亚胺化合物的合成和荧光性能

采用收敛法合成了3代内核为1,4,5,8-萘酰亚胺, 端基分别含8个和16个乙基的三嗪树枝状大分子, 产物经IR, 1H NMR, 13C NMR及元素分析表征. 实验结果表明, 该方法无需保护/脱保护, 反应条件温和, 收率非常高. 通过荧光光谱对其荧光特性进行了初步研究, 发现经过树枝状修饰后的产物具有更好的荧光性能, 且随着代数的增加, 树枝状产物的荧光强度不断增强.     

5-取代-1H-1,2,4-三氮唑-3-羧酸的合成

三氮唑类化合物具有很强的生物活性[1,2],尤其是利用5 氨基 1H 1,2,4 三氨唑 3 羧酸为原料制得的Schiff碱具有较强的生根性能和较好的细胞分裂活性[3,4]本文以5 氨基 1H 1,2,4 三氨唑 3 羧酸为原料,经Sandmeyer反应将 NH2转变 Cl、 Br、 I和 CN。其合成路线如下:1　实验部分1 1　仪器与试剂Impact 420型傅里叶红外光谱仪;HP8452A二极管阵列紫外/可见光光度计;PE 2400型元素自动分析仪:XL 200MHz超导核磁共振仪;M 80AGC/MS质谱仪。5 氨基 1H 1,2,4 三氮唑 3 羧酸(工业纯,武汉中储鹤翔新技术有限公司,纯度95%以上),其余试剂均…     

Intramolecular titanium-promoted deoxygenative cyclization to 9-substituted-1,2,3,4-tetrahydrofluorene skeleton

The Mukaiyama aldol reaction of 2-aryl-1-cyclohexene-1-carboxaldehydes with phenyl trimethylsilyl ketene acetal unexpectedly resulted in the formation of 9-substituted-1,2,3,4-tetrahydrofluorene derivatives via a novel intramolecular titanium-promoted deoxygenative cyclization. By successive treatment of the corresponding allyl alcohols with n-butyllithium and titanium tetrachloride, the cyclization products were obtained in good yields.     

Synthesis of some 1-substituted-3-or-5-styrylpyrazoles

The synthesis of the title compounds by the Wittig-Horner reaction is described, using the 3-or-5-hydroxymethylpyrazole derivatives as precursors.     

Synthesis of 3-alkyl-8-substituted- and 4-hydroxy-8-substituted-2,3,4,5-tetrahydro-1H-2-benzazepines

Based on the Schmidt reaction and an iodolactone ring expansion reaction, two different synthetic routes to substituted 2,3,4,5-tetrahydro-1H-2-benzazepines were developed. The Schmidt reaction on 2,3-dihydro-2H-1-naphthalenone ( 1 ) gave 3 , the product resulting from the alkyl group migration, as the major product instead of the tetrazole 2. This prompted the investigation of the Schmidt reaction on aromatic ketones 8 and 12. The product 9 due to alkyl group migration was the major product of the Schmidt reaction on 2-methyl-3,4-dihydro-2H-1-naphthalenone ( 8 ). The β-keto diester 12 gave a mixture of decarb-oxylated lactams after the Schmidt reaction. In this case, the lactam 13 resulting from the migration of the aromatic ring dominated over the other lactam 14. When lactam 14 was subjected to nitration, a single regioisomer was produced and transformed to the bromo alcohol 19. The other approach was based on the single pot ring expansion of the iodolactone 22 to the lactam 23 in the presence of methanolic ammonia. The iodolactone 22 was readily prepared from 2-allylbenzoic acid.     

Synthesis of nucleosides of 5-substituted-1,2,4-triazole-3-carboxamides

Nucleosides of 5-substituted-1,2,4-triazole-3-carboxamides were prepared by the acid-catalyzed fusion procedure and by glycosylation of the appropriate trimethylsilyl derivative. The following nucleosides were obtained in two steps starting from methyl 4-substituted-1,2,4-triazole-3-carboxylates: 5-chloro-1-β- D -ribofuranosyl-1,2,4-triazole-3-carboxamide ( 6 ), 3-chloro-1-β- D -ribofuranosyl-1,2,4-triazole-5-carboxamide ( 5 ), 3-nitro-1-β- D -ribofuranosyl-1,2,4-triazole-5-carboxamide ( 12 ), 3-amino-1-β- D -ribofuranosyl-1,2,4-triazole-5-carboxamide ( 13 ), 5-methyl-1-β- D -ribofuranosyl-1,2,4-triazole-3-carboxamide ( 15 ), and 3-methyl-1-β- D -ribofuranosyl-1,2,4-triazole-5-carboxamide ( 16 ). In addition, 5-amino-1-β- D -ribofuranosyl-1,2,4-triazole-3-carboxamide ( 7 ), and 1-β- D -ribofuranosyl-1,2,4-triazole-3-carboxamide-5-thiol ( 8 ) were prepared from 6 .