SYNTHESIS AND PROPERTIES OF COPOLYMERS FROM 1-[3,5-BIS(TRIMETHYLSILYL)PHENYL]-2-PHENYLACETYLENE

Copolymerization of 1-[3,5-bis(trimethylsilyl)phenyl]-2-phenylacetylene (m,m-(Me₃Si)₂DPA) with other diphenylacetylene derivatives and their copolymer properties were investigated. Homopolymerization of m,m-(Me₃Si)₂DPA by TaCl₅─n-Bu₄Sn (1:2) did not give the polymer due to steric hindrance. However, m,m-(Me₃Si)2DPA copolymerized with diphenylacetylene (DPA), 1-phenyl-2-[p-(trimethylsilyl)phenyl]acetylene (p-Me₃Si DPA), and 1-phenyl-2-[m-(trimethylsilyl)phenyl]acety-lene (m-Me₃SiDPA) in the presence of TaCl₅─n-Bu₄Sn at various feed ratios to give copolymers in moderate yields. The formed copolymers were yellow to orange solids, which were soluble in common organic solvents such as toluene and CHCl₃. The highest weight-average molecular weights (M_w) of these copolymers reached ca. 6 × 105 and tough films could be obtained by solution casting. Their onset temperatures of weight loss in air were observed around 400°C, indicating high thermal stability. The oxygen permeability coefficients at 25°C of copoly(m,m-(Me₃Si)₂ DPA/DPA) (feed ratio 1:1) and copoly(m,m-(Me₃Si)₂DPA/p-Me₃SiDPA) (feed ratio 1:2) were 21 and 100 barrers, respectively, medium in magnitude among polymers from substituted acetylenes.     

The ion kinetic energy and mass spectra of isomeric methyl indoles

The mass spectra of the seven isomeric methylindoles were recorded and the [metastable ion]/[daughter ion] ratios for the reactions m/e 130 → m/e 103 and m/e 103 → m/e 77 have been obtained. The ratios indicate that the decomposing [M — 1] ions (m/e 130) from the 4, 5, 6 and 7 isomers are energetically similar as are the [M — 1] ions from the 2 and 3 isomers. The results observed for the m/e → 103 m/e 77 reaction showed that the decomposing m/e 103 ions from the 2, 3, 4, 5, 6 and 7 isomers all have the same energy distribution. N-Methylindole gave ratios which were similar to the 4 to 7 isomers at 70eV but different at 20 eV. The ion kinetic energy (IKE) spectra of all the isomeric methylindoles were also obtained and the results compared with the data obtained from the [metastable ion]/[daughter ion] approach. The results from the IKE spectra indicated that the energy distributions of the [M — 1] and [(M — 1) — HCN] ions from 1-methylindole and the [(M — 1) — HCN] ions from 2-methylindole could readily be distinguished from other isomers whose [metastable ion]/[daughter ion] ratios were similar. Thus by using both techniques certain ambiguities can be resolved.     

Bemerkungen zur Synthese von 5-Amino-m-xylol-2-sulfonsäure und 5-Amino-m-xylol-4-sulfonsäure

Some comments on the syntheses of 5-amino-m-xylene-2-sulfonic acid and 5-amino-m-xylene-4-sulfonic acid Treatment of 5-amino-m-xylene ( 1 ) with oleum led to a 55:45 mixture of 5-amino-m-xylene-2-sulfonic acid ( 2 ) and 5-amino-m-xylene-4-sulfonic acid ( 3 ). The structure of both isomers was proven by reaction of sulfur dioxide with the diazonium chlorides derived from 2-amino-5-nitro-m-xylene ( 5 ) and 4-amino-5-nitro-m-xylene ( 8 ) giving 5-nitro-m-xylene-2-sulfonyl chloride ( 6 ) and 5-nitro-m-xylene-4-sulfonyl chloride ( 9 ) respectively, followed by hydrolyses to the corresponding sulfonic acids 7 and 10 , and final Béchamp reductions. The sulfonic acid 2 was also prepared by sulfonation of 5-acetylamino-m-xylene ( 4 ) to 5-acetylamino-m-xylene-2-sulfonic acid ( 11 ) and subsequent hydrolysis. A further procedure for the synthesis of 3 was sulfonation of 5-amino-2-chloro-m-xylene ( 12 ) – prepared by Béchamp reduction of 2-chloro-5-nitro-m-xylene ( 13 ) – or of 5-amino-2-bromo-m-xylene ( 15 ) – prepared by bromination of 4 and subsequent hydrolysis – to 5-amino-2-chloro-m-xylene-4-sulfonic acid ( 16 ) and 5-amino-2-bromo-m-xylene-4-sulfonic acid ( 17 ) respectively, followed by hydrogenolysis.     

芳香桥式双(苯并氮杂-15-冠-5)的合成及其对碱金属和重金属离子的选择键合

通过11,12-苯并-1,7,10,13-四氧杂-4-氮杂环十五烷-11-烯(苯并氮杂-15-冠-5)分别与间二苄溴, 间苯二甲酰氯和对苯二甲酰氯反应, 合成了N,N'-间二苄基双(苯并氮杂-15-冠-5) (1)、N,N'-间苯二甲酰基双(苯并氮杂-15-冠-5) (2)和N, N'-对苯二甲酰基双(苯并氮杂-15-冠-5) (3) 等三个芳香桥式双(苯并氮杂-15-冠-5)衍生物, 并解析了化合物3的晶体结构. 进而采用溶剂萃取的方法研究了它们与一价金属阳离子的键合行为. 结果表明, 双冠醚2对碱金属钠离子和重金属铊离子表现出较高的选择萃取能力, 而双冠醚1对重金属银离子表现出较高的选择萃取能力.     

由3-二茂铁-2-丁烯酸根和1,10-邻菲啰啉构筑的一维链状铅(II)配位聚合物的合成、晶体结构及电化学性质

Pb(OAc)₂•3H₂O, 3-二茂铁-2-丁烯酸钠以及1,10-邻菲啰啉在甲醇中反应得到了铅的配位聚合物: [Pb(m-OOCCH＝C(CH₃)Fc)(m₂-OOCCH＝C(CH₃)Fc)(phen)]_n (Fc＝(h⁵-C₅H₅)Fe(h⁵-C₅H₄); phen＝1,10-邻菲啰啉). 单晶测试表明: 每个铅离子为六配位, 其中4个氧原子来自4个3-二茂铁-2-丁烯酸根, 另2个氮原子来自邻菲啰啉; 相邻的铅离子通过3-二茂铁-2-丁烯酸根的单齿和双齿氧原子桥连形成了一个无限的一维长链. 研究了标题化合物在DMF溶液中的电化学性能.     

Synthetische untersuchungen zum reaktionsverhalten von 2-phenyl-5-oxo-5H-naphtho[1,8-bc] thiophen — thia-pseudophenalenon

The reactivity of 2-phenyl-5-oxo-5H-naphtho[1,8-bc]thiophene ( 1 ) with the N-sulfonyl-heterokumulenes ( 2a-2c, 2d-2e. 2f-2k ) was of interest. We obtained the N-sulfonylimino-pseudophenalenones ( 5a-5k ). Phenylisocyanate and m-chlorophenylisocyanate reacted with 1 only in the presence of the Lewis acid anhydrous aluminum chloride to give the derivatives 6a and 6b . From diphenylketene ( 7 ) and 1 we obtained the pseudophenafulvene 8 , and from the fluorenketene ( 9 ) and 1 we obtained the pentapseudophenafulvalene 10 .     

Site of alkylation of N-methyl- and N-ethylaniline in the gas phase: a tandem mass spectrometric study

N-Methylaniline (NMA) was ethylated and N-ethylaniline (NEA) was methylated under chemical ionization conditions using C₂H₅I and CH₃I, respectively, as reagent gases. The structures of the resulting m/z 136 adduct ions have been probed using metastable ion and collision-induced dissociation (CID) methods. From the similarity of the spectra obtained and from the presence of structure-diagnostic ions at m/z 59 (CH₃NHC₂H₅^+•) and m/z 44 (CH₃NHCH₂⁺), it is concluded that predominantly N-alkylation occurs in both systems. This interpretation was aided by the use of C₂D₅I and CD₃I as reagents. Adduct ions of m/z 136 were also formed by ethylation of the isomeric toluidines and by methylation of the ring-ethylanilines. The resulting CID mass spectra were distinctly different from those obtained for the m/z 136 ions obtained by alkylation of NMA and NEA. Protonation of N-ethyl-N-methylaniline using CH₃C(O)CH₃ as Brønsted acid reagent produced an m/z 136 species whose CID mass spectrum also featured intense ion signals at m/z 59 and 44. This observation led to the conclusion that protonation with acetone as reagent results, in this case, in dominant N-protonation. However, the CID mass spectrum of the m/z 136 ion formed when CH₃OH was the protonating agent featured a weak signal at m/z 44 and no signal at m/z 59. Hence it was concluded that the latter m/z 136 ion contains a larger contribution from the ring-protonated adduct. Copyright © 2004 John Wiley & Sons, Ltd.     

Controllable Topological Transformations of 818 Molecular Metalla-knots by Oxidation of Thiazole-Based Ligands

By exploiting coordination-driven self-assembly, high yields of two 8₁₈ molecular metalla-knots could be obtained using a thiazole-moiety-containing asymmetric dipyridyl ligand 2-(pyridin-4-yl)-5-(pyridin-4-ylethynyl)benzo[d]thiazole ( L₁ ), as confirmed using X-ray crystallographic analysis, electrospray ionization-time-of-flight/mass spectrometry (ESI-TOF/MS), and detailed liquid-state nuclear magnetic resonance (NMR) spectroscopy. To modulate the self-assembled structures, m-chloroperbenzoic acid (m-CPBA) was utilized to oxidize thiazole-based ligand L₁ to N-thiazole-oxide-based ligand 2-(pyridin-4-yl)-5-(pyridin-4-ylethynyl)benzo[d]thiazole 3-oxide ( L₂ ), which enabled the selective construction of the corresponding tetranuclear macrocycles. Notably, two molecular metalla-knots could be topologically transformed from 8₁₈ knots to simple monocycles because the L₁ alkyne bond was inert toward m-CPBA, as confirmed by liquid-state NMR spectroscopy, ESI-TOF/MS, and elemental analysis.     

A Novel Conversion of 2, 4‐Diaryl‐2, 3‐dihydro‐1 H‐1, 5‐benzodiazepines into 2, 4‐Diaryl‐3 H‐1, 5‐benzodiazepines

A novel conversion of 2, 4‐diaryl‐2, 3‐dihydro‐1 H‐1, 5‐benzodiazepins into 2, 4‐diaryl‐3 H‐1, 5‐benzodiazepines by the reaction with m‐chloroperbenzoic acid (MCPBA) was reported.     

Synthesis,characterisation and thermal behaviour of some complexes with ligands having 1,3,4-thiadiazole moieties

Summary The investigations concerning the thermal behaviour of a series of Ni(II) and Cu(II) complexes of type [MLCl_n]·mH₂O ((1) M:Ni, L:L(1), n=1, m=2; (2) M:Cu, L:L(2), n=1, m=2; (3) M:Ni, L:L(3), n=2, m=0; (4) M:Cu, L:L(3), n=1, m=2) are presented in this paper. The ligands L(1)-L(3) have been synthesised by template condensation of 1,2-diaminoethane with formaldehyde and 2-amino-1,3,4-thiadiazole-5-thiole or 2-acetamino-1,3,4-thiadiazole-5-sulfonamide. The bonding and stereochemistry of the complexes have been characterised by IR, electronic and magnetic studies at room temperature. The thermal behaviour provided confirmation of the complex composition as well as the number and the nature of water molecules and the intervals of thermal stability. The different nature of the ligands and/or the metallic ions generates a different thermal behaviour for complexes. The complexes do not show biological activity against HIV virus.     

Identification of m-Mentha-3(8),6-diene (Isosylveterpinolene) in Black Pepper Oil

m-Mentha-3(8),6-diene (&sequals n01; isosylveterpinolene; 5 ), which has not been found in nature before, was shown by GC/MS analysis and co-injection with a synthetic sample to be present to the extent of 0.12 – 0.17% in black and green pepper oil. The synthetic reference 5 was prepared by deconjugation of 3-methylcyclohex-2-en-1-one ( 1 ), subsequent alkylation with lithium 2-lithio-2-methylpropanoate, and decarboxylative dehydration of the resulting hydroxycarboxylic acid 3 employing dimethylformamide dimethyl acetal. On polar GC columns, 5 was eluted between p-cymene and terpinolene, and was characterized by an MS similar to that of terpinolene, but with the fragment m/z 121 (59, [M−Me]⁺) being less intense than that of the molecular ion at m/z 136 (67, M⁺). Since m-mentha-3(8),6-diene was also found to the extent of 0.24% in the headspace of ground black peppercorns, it can be considered to be of genuine natural origin, and thus is the first established example of a naturally occurring m-menthadiene.     

Nucleotides. Part LXXII

The synthesis of various N‐methylated nucleosides (m⁶A, m³C, m⁴C, m³U) is described. These minor nucleosides can be obtained by simple methylation with diazomethane of [2‐(4‐nitrophenyl)ethoxy]carbonyl(npeoc)‐protected nucleosides. These methylated compounds are easily further derivatized to fit into the scheme of the [2‐(dansyl)ethoxy]carbonyl (dnseoc) approach for RNA synthesis (dansyl=[5‐(dimethylamino)naphthalen‐1‐yl]sulfonyl). Various oligoribonucleotides containing N⁶‐methyladenosine were synthesized, underlining the usefulness of the dnseoc approach, especially for the synthesis of natural tRNA‐derived oligoribonucleotide sequences.     

Fluorinated 1,3-diketones, 2-trifluoroacetyl phenols and their derivatives: versatile reactants in phosphorus chemistry

The role of fluorinated β-diketones, their tautomers (keto–enols) and their derivatives as reagents towards λ³P compounds is reviewed, including 2-trifluoroacetyl phenols, possessing formally a keto–enol system, and their derivatives. In an ‘insertion’ reaction phosphine and the keto–enol tautomers of 1,1,1,5,5,5-hexafluoro- and 1,1,1-trifluoropentan-2,4-dione furnished primary (S) or (R) α-hydroxy phosphines, whose enol functions probably isomerized the corresponding keto compounds. Further addition and isomerisation furnished 1,3α,5,7β-tetrakis(trifluoromethyl)-2-phospha-6-oxa-9-oxabicyclo[3.3.1]-nonan-3β,7α-diol and 1,7-trifluoromethyl-3,5-methyl-2,4,8-trioxa-6-phophaadamantane, exclusively one diastereomer in each case. The main mechanistic feature of these reactions is a consecutive diastereoselective hemiketal cyclization. 1,1,1,5,5,5-Hexafluoro- and 1,1,1-trifluoropentan-2,4-dione, as well as 2-trifluoroacetyl phenol and its imino derivatives reacted diastereospecifically with phosphonous acid dichlorides, RPCl₂ to give in a concerted mechanism thermally stable tricyclic λ⁵σ⁵P phosphoranes containing two five-membered rings and one six-membered ring. Surprisingly, the two CF₃ groups bonded to an sp³-hybridized carbon were in a cisoid arrangement having closest non-bonding FF distances of 301.4 or 273.5 pm. These findings reflect the ‘through space’ F---F coupling constants of the tricyclic phosphoranes (J_FF=4.0–7.0 Hz), in solution. 4,4,4-Trifluoro-3-hydroxy-1-phenyl-butan-1-one and methyl or phenyl phosphonous acid dichlorides gave similar tricyclic phosphoranes decomposing at ambient temperature to furnish 1,2λ⁵σ⁴-oxaphospholanes and (E)-1,1,1-trifluoro-4-phenyl-but-2-en-4-one. Dialkylphosphites and 1,1,1,5,5,5-hexafluoropentan-2,4-dione reacted to give either the (Z)-enol phosphonates or the respective γ-ketophosphonates from which in two cases four diastereomeric 2-oxo-2,5-dialkoxy-3,5-bis(trifluoromethyl)-3-hydroxy-1,2λ⁵σ⁴-oxa-phospholanes were obtained. 2-Trifluoroacetyl cyclohexanone, 4,4,4-trifluoro-3-trimethylsiloxy-1-phenylbutan-1-one, 1-benzoyl-2-trifluormethyloxirane, 1-benzoyl-2-trifluoro-methylaziridine, 2-trifluoroacetyl-1-trimethylsiloxybenzene and (trifluoroacetyl-1-phenyl) diethyl phosphate reacted with tris(trimethylsilyl) phosphite to give functionalized α-trimethylsiloxy phosphonates, which could easily be transferred into the respective phosphonic acids. In the case of an oxirane and an aziridine ketone no ring cleavage was observed. For 1,1′-(2-hydroxy-5-methyl-m-phenylene)-bis-ethanone and 1,1′-(2-trimethylsiloxy-5-methyl-m-phenylene)-bis-ethanone benzoxaphospholanes were obtained. Trialkyl phosphites and 1,1,1,5,5,5-hexafluoropentan-2,4-dione furnished cyclic phosphoranes containing the 3-hydroxy-3,5-bis(trifluoromethyl)-1,2λ⁵σ⁵-oxaphospholene structural element, stable at ambient temperature only in the case of one cyclic phosphite precursor. (E)-1,1,1-Trifluoro-4-phenyl-but-2-en-4-one and trimethylphosphite reacted to form 1,2λ⁵σ⁵-oxaphosphol-4-ene as the sole product. Results similar to the reaction of 1,1′-(2-hydroxy-5-methyl-m-phenylene)-bis-ethanone with diethyltrimethylsilylphosphite were obtained for trimethylphosphite and 2-trifluoroacetyl phenol where a deoxygenated phosphorane was found, easily hydrolyzed to give the respective phosphonic acid. With dialkylisocyanato phosphites and the keto components, 1,1,1,5,5,5-hexafluoro- and 1,1,1-trifluoropentan-2,4-dione, 4,4,4-trifluoro-1-phenyl-1,3-butandione, 2-trifluoroacetyl cyclohexanone, 2-trifluoroacetyl phenol and 1,1′-(2-hydroxy-5-methyl-m-phenylene)-bis-ethanone reacted in a ‘double’ cycloaddition to form bicyclic phosphoranes containing the 4,8-dioxa-2-aza-1λ⁵σ⁵-phosphabicyclo[3.3.0]-oct-6-en-3-one ring system; for the imino derivatives of 2-trifluoroacetyl phenol a corresponding 8-oxa-2,4-diaza- system was generated. For (E)-1,1,1,5,5,5-hexafluoro-4-trimethylsiloxy-3-penten-2-one however, a cyclic spiroimino phosphorane was obtained which underwent a [2+2] cyclodimerization to form a diazadiphosphetidine. Dimethylpropynyl phosphonite and 1,1,1,5,5,5-hexafluoropentan-2,4-dione yielded diastereoselectively a bisphosphorane, namely 1,4-bis(trifluoromethyl)-3,6-dioxa-2,2,7,7-tetramethoxy-2,7-di(1-propynyl)-2,7-diphosphabicyclo[2.2.1] heptane. When trimethylsilanyl–phosphenimidous acid bis-trimethylsilanyl–amide, Me₃SiN=PN(SiMe₃)₂, was allowed to react with 1,1,1,5,5,5-hexafluoro- and 1,1,1-trifluoropentan-2,4-dione, (E)-1,1,1,5,5,5-hexafluoro-4-trimethylsiloxy-3-penten-2-one, 2-trifluoroacetyl cyclopentanone, 2-trifluoroacetyl phenol and its imino derivatives, 2-imino-1,2λ⁵σ⁴-oxaphospholenes were found containing two diastereomers in each case, which added hexafluoroacetone across the P=N bond to give 1,3,2λ⁵σ⁵-oxazaphosphetanes.     

Synthesis and Properties of Nonpolar DNA (Arylalkyl)phosphonates

The eight (arylalkyl)‐modified phosphoramidites (=(arylalkyl)phosphonamidites) 1 – 8 (Fig. 2) were synthesized (Schemes 1–3) and incorporated at different positions into 2′‐deoxyoligonucleotides. The [P(R)]‐ and [P(S)]‐diastereoisomers of the hexanucleotides 32 – 39 (Table 1) and of the dodecanucleotides 41 – 45 (Table 2) obtained were separated by means of reversed‐phase HPLC. UV, CD, and fluorescence spectroscopy were used to investigate the thermal stability (T_m) and the structural changes of their DNA duplexes with 5′‐d(CGCGCG)‐3′ and 5′‐d(ATGATTGACCTG)‐3′, respectively. The T_m values significantly depend on the place of modification (Table 2). A dangling‐end effect is observed when the [3‐(anthracen‐9‐yl)propyl]‐modified 8 is attached at the 5′‐terminus (see duplex with 45c ). In the case of the incorporation of aromatic moieties tethered via a methylene linker to the P‐atom (benzyl‐ and (naphthalen‐1‐ylmethyl)‐modified 1 and 6 , resp.), the duplexes with the [P(R)]‐oligonucleotides are more stable than those with the [P(S)]‐isomers, whereas in the case of longer alkyl chains at the P‐atom (see 2 – 5 ), the T_m values show the reverse tendency. The observed T_m differences are assigned to changes in base stacking (Figs. 6 and 7).     

稀土与N-对甲苯磺酰甘氨酸配合物的合成、晶体结构与性质

Complexes { [Ln（H20）2（TsGlyH）a]m·nH2O}∞ （Ln=La （1）, m=2, n=6; Nd （2）, m=2, n=7; Eu （3）, m=2, n= 0; Gd （4）, m=2, n=2; Er （5）, m=3, n=5 and Yb （6）, m=3, n=0, TsGlyH=N-p-tosylglycine monoanion）, have been prepared and characterized by IR spectra, elemental analysis, and TG-DTG 4 and 5 were structurally determined by X-ray diffraction analysis, showing that both of them are comprised of a one dimensional chain structure established via the coordination of μ-carboxylate groups from N-p-tosylglycinate to the corresponding lanthanide（Ⅲ） ions. The one dimensional chains were found inclined to form two-dimensional network via hydrogen bonding and then three dimensional network structure via non-classical hydrogen bonding. The fluorescence spectra of them revealed that the fluorescence of the ligand was quenched by Ln（Ⅲ） ions. In the tested biological activity experiments, they behaved inhibiting effects against the growth of bacteria, indicating that it is a potential medicament worthy of further investigation.     

Potential cerebral perfusion agents. Synthesis and evaluation of new radioiodinated barbituric acid analogs

Two new ¹²⁵I-labeled barbituric acid analogs, 5-ethyl-5-(E-1-iodo-1-penten-5-yl)2-thiobarbituric acid ( 4 ) and 5-ethyl-5-( m -iodophenyl)barbituric acid ( 7 ), have been prepared and evaluated in rats as potential cerebral perfusion agents. Annulation of 2-ethyl-2-(E-1-iodo-1-penten-5-yl)malonate ( 3 ) with thiourea in the presence of sodium ethoxide gave the 5-ethyl-5-(E-1-iodo-1-penten-5-y1)-thiobarbituric acid ( 4 ). Diethyl 2-ethyl-2-phenyl-malonate was treated with thallium(III) trifluoroacetate followed by addition of aqueous potassium iodide to provide diethyl 2-ethyl-2-(m-iodophenyl)malonate ( 10 ). The malonic ester derivative 10 was condensed with urea in the presence of sodium hydride to give the desired 5-ethyl-5-(m-iodophenyl)barbituric acid ( 7 ), and a decarbethoxylation product, 2-(m-iodophenyl)butyric acid ( 11 ). Iodine-125-labeled 4 and 7 were synthesized in the same manner and the tissue distribution of these new agents evaluated in rats. Both [¹²⁵I] 4 and [¹²⁵I] 7 showed high brain uptake. Significant in vivo deiodination was detected with [¹²⁵I] 4 whereas [¹²⁵I] 7 was found to be stable to deiodination.     

New complex oxides of the A3n+3mA′nB3m+nO9m+6n family: Ba6A′Mn4O15 (A′=Mg, Ni)

Complex oxides Ba₆AMn₄O₁₅, where A=Mg (I) and Ni (II), belonging to the homologous series A_3n+3mA′_nB_3m+nO_9m+6n (n=1, m=1) were obtained by solid state reaction method from Ba carbonate and oxides MgO, NiO, MnO₂. Both new oxides are incommensurate. Their crystal structures were interpreted as composite ones with two subcells: a=10.042(3) Å, c₁=4.318(2) Å, c₂=2.565(1) Å, c₁/c₂=1.6834 for (I) and a=10.044(3) Å, c₁=4.308(2) Å, c₂=2.551(1) Å, c₁/c₂=1.6887 for (II). Magnetic susceptibility measurements in the range 2–850 K revealed antiferromagnetic correlations in Ba₆MgMn₄O₁₅ (T_N=7 K) and a pseudo-square-planar environment of some Ni²⁺ cations in Ba₆NiMn₄O₁₅.     

Synthesis of two metabolites of 2,4-diamino-5(3,4,5-trimethoxybenzyl)-pyrimidines (Trimethoprim)

The synthesis of two metabolites M₃ and M₄ of 2,4-diamino-5-(3, 4, 5-trimethoxybenzyl)-pyrimidine (trimethoprim, 1 ) is reported. M₃ (trimethoprim 1-oxide) as well as the isomeric 3-oxide were prepared by oxidation of 1 with m-chloroperbenzoic acid. The structure of M₃ was finally established by x-ra analysis [4]. The metabolite M₄ [2, 4-diamino-5-(3-hydroxy-4, 5-dimethoxy-benzyl)-pyrimidine] was prepared by condensation of 3-benzyloxy-4, 5-dimethoxybenzaldehyde ( 2 ) with 3-methoxypropionitrile ( 3 ) and guanidine followed by hydrogenolysis of the intermediate 3-benzyloxy compound 4 .     

新型3-取代-6-(4-氯苯基)-7-(1H-1,2,4-三唑-1-基)-1',2',4'-三唑[3,4-b]-1",3",4"-噻二嗪衍生物的合成及抗菌活性

通过3-取代-4-氨基-5-巯基-1,2,4-三唑(3a～3m)和2-溴-2-(1H–1,2,4-三唑-1-基)-4′-氯代苯乙酮(2)的缩合反应, 合成了13个新型3-取代-6-(4-氯苯基)-7-(1H-1,2,4-三唑-1-基)-1',2',4'-三唑[3,4-b]-1",3",4"-噻二嗪衍生物4a～4m. 化合物结构经元素分析, ¹H NMR, IR和MS进行了表征. 抗菌试验表明所合成的化合物对细菌表现出中等程度的抑制活性.     

Cleavage of NpzCH2 -OP and unexpected formation of bis(3,5-dimethyl-1H-pyrazol-1-yl)methane (dmbpm): X-ray crystal structure of [PdCl2(dmbpm)]

In the reaction of (3,5-dimethyl-1H-pyrazol-1-yl)methyldiphenylphosphinite (dmpmp) with [PdCl₂(CH₃CN)₂], we have obtained hydrolysis and phosphorus oxidation products and the unexpected complex cis-[PdCl₂(dmbpm)] (dmbpm = bis(3,5-dimethyl-1H-pyrazol-1-yl)methane). Modifications in the synthesis of dmpmp (high temperature, strong base, and the presence of Ph₂P(O)Cl) show that dmbpm is a by-product from the synthetic route to dmpmp. The complex cis-[PdCl₂(dmbpm)] is isolated and fully characterized by mass spectrometry, analytical, and spectroscopy techniques and the crystal structure is obtained by X-ray diffraction methods.