Marine natural products. XXVI. Biologically active tridecapeptide lactones from the Okinawan marine sponge Theonella swinhoei (Theonellidae). (2). Structures of theonellapeptolides Ia, Ib, Ic, and Ie

Five tridecapeptide lactones, named theonellapeptolides Ia (1), Ib (2), Ic (3), Id (4), and Ie (5), were isolated from the Okinawan marine sponge Theonella swinhoei. Following the structure elucidation of theonellapeptolide Id (4), the structures of theonellapeptolides Ia (1), Ib (2), Ic (3), and Ie (5) were determined on the basis of chemical and physicochemical evidence including high performance liquid chromatography and circular dichroism combined analysis of the amino acid compositions. Theonellapeptolides Ib (2), Ic (3), Id (4), and Ie (5) exhibit moderate cytotoxic activity towards for L1210 in vitro (IC50 1.6, 1.3, 2.4, and 1.4 micrograms/ml, respectively), and theonellapeptolide Ie (5) exhibits ion-transport activities for Na+ and K+ ions.     

Mass spectral studies of some aryl and aroyl derivatives of glyoxime

Mass spectra of two diaroylglyoximes (Ia and Ib) are reported and compared with those of the corresponding dehydration products, 3,4-diaroyl-1,2,5-oxadiazoles (IIIa and IIIb, respectively). In Ia and Ib, unlike in diarylglyoximes (Id and Ie), the largest ion is [M — 18]⁺, but this does not form in the ion source by a simple thermal dehydration. Similar spectra have been obtained for an alkyl aroyl derivative of glyoxime (Ic) and an isonitroso-β-diketone (II). A specific electron-impact-induced rearrangement leading to the formation of carboxylic acids has been observed in the mass spectra of all the acylated oximes under investigation.     

Effects of substituents on the stabilities of phosphonyl radicals and their hydroxyphosphinyl tautomers

High-level ab initio quantum chemical methods have been used to calculate the radical stabilization energies (RSEs) of phosphonyl radicals XYP(=O)* bearing a range of substituents X and Y. The main influences on these radicals' stabilities are sigma-effects. Due to the high positive charge on phosphorus, sigma-withdrawal is destabilizing, and sigma-donation is stabilizing. The pyramidal geometry at phosphorus minimizes the effect of stabilization by pi-delocalization, while the potentially stabilizing effect of lone-pair donation is outweighed by concomitant sigma-withdrawal. Thus, the calculated RSEs of phosphonyl radicals XHP(=O)* increase in the order X = F < Me(3)N+ < MeO < CF3 < tBu < Me(2)N < NC < H < Ph < MeS < Me(3)Si. The tautomeric hydroxyphosphinyl radicals X(OH)P. exhibit a different set of substituent effects, with RSEs increasing in the order X = CF3 < Me(2)N < Me(3)N+ < MeO < (t)Bu < H < MeS < Me(3)Si < F < NC < Ph. In these radicals, both the sigma- and pi-properties of the X substituent influence stability, in tandem with those of the OH group. A comparison of the absolute enthalpies of isomeric phosphonyl and hydroxyphosphinyl radicals indicates that the hydroxyphosphinyl radicals X(OH)P* are more stable than the phosphonyl radicals XYP(=O)*. This is not a common situation in phosphorus chemistry. It is primarily attributed to the greater phosphorus p character of the singly occupied molecular orbital (SOMO) in the hydroxyphosphinyl radicals compared with the phosphonyl tautomers. As in closed-shell phosphorus species, the magnitude of the effect is modulated by the electronegativity of the substituent X.     

Study on the Interfacial Tensions Between Oils and Alkylbenzene Sulfonate Gemini Surfactant Solutions

Interfacial tensions (IFT) of five alkylbenzene sulfonate Gemini surfactants Ia, Ib, Ic, Id, and Ie at different oils/water systems were measured by a spinning drop interfacial tensiometer. And critical micelle concentration (CMC), the interfacial tension at CMC (γ_CMC), maximum interfacial excess concentration (Γ _max) and the surface area per molecule (A_min) were calculated. The results indicated that the CMC values determined with interfacial tension method were lower than those determined with surface tension method. And γ_CMC for Ie is larger than that for Ia, Ib, Ic, and Id. In addition, the effects of temperature and hydrophobic chains on dynamic IFT were also studied. With the increment of temperature, dynamic IFT is easier to reach a stable value. However, with the increment of hydrophobic chains, dynamic IFT is more difficult to reach a stable value. Each Gemini surfactant produces a minimum IFT when measured against a different n-alkane.     

Polymerization systems driven by aromatization energy: Anionic polymerization of 4-allylidene-2,6-dimethyl-2,5-cyclohexadien-1-one and spiro[2,5]octadienone derivatives

To investigate the polymerization systems driven by aromatization energy, 4-allylidene-2,6-dimethyl-2,5-cyclohexadien-1-one ( Ia ), 5,7-dimethyl-1-vinylspiro[2,5]octa-4,7-dien-6-one ( Ib ), 4,7-dimethyl-1-vinylspiro[2,5]octa-4,7-dien-6-one [ Ic ], 2-vinyl-2′-methylspiro[cyclopropane-1,4′-(1′-naphthalenone)] ( Id ), and 2-phenyl-2′-methylspiro[cyclopropane-1,4′-(1′-naphthalenone)] ( Ie ) were prepared and polymerized with sodium cyanide in N,N-dimethylformamide. Monomer Ia was highly polymerizable even at ?65°C. Monomers Ib–Ie also polymerized well, giving powdery polymers that were soluble in common solvents. All the polymerizations took place through the aromatization of the cyclohexadienone ring, suggesting that the aromatization energy is the driving force for the polymerization of these monomers.     

Polymerizations of substituted cyclopropanes. I. Radical polymerization of 1,1-disubstituted 2-vinylcyclopropanes

Diethyl 2-vinylcyclopropane-1,1-dicarboxylate (Ia), 2-vinylcyclopropane-1,1-dicarbonitrile (Ib), ethyl 1-cyano-2-vinylcyclopropanecarboxylate (Ic), and 1,1-diphenyl-2-vinylcyclopropane (Id) were radically homo- and copolymerized. Ia, Ib, and Ic polymerized cleanly in 1,5-type ring-opening fashion to yield polymers of high molecular weight. Id failed to homopolymerize but copolymerized with common monomers which included maleic anhydride. Infrared (IR) spectra indicated that the double bonds of the polymer chains were in trans form. All polymers were soluble in solvents and solution-cast films were clear and flexible, showing T_g values in the 25–40°C range. Model reactions of those monomers with benzenethiol also indicated predominant 1,5-addition reactions. From the results of our investigation it was concluded that the driving force for the facile radical 1,5-polymerization of Ia, Ib, and Ic was the stabilization of growing radicals by two substituents.     

Rearrangement of 1,4-benzodiazepin-2,4-diones to 3,l-benzoxazin-4-ones

Treatment of 7-chloro-3,4-dihydro-1H-1,4-benzodiazepin-2,5-dione (Ia) with refluxing acetic anhydride in the presence of pyridine afforded 6-chloro-2-methyl-4H-3,1-benzoxazin-4-one (IIa). A plausible reaction path for this novel rearrangement reaction is described: Ia → 4-acetyl-7-chloro-3,4-dihydro-lH-1,4-benzodiazepin-2,5-dione → 7-chloro-1,4-diacetyl-3,4-dihydro-lH-1,4-benzodiazepin-2,4-dione → IIa. When 7-chloro-3,4-dihydro-4-methyl-lH-1,4-benzodiazepin-2,5-dione (Ib), 3,4-dihydro-4-methyl-1H-1,4-benzodiazepin-2,5-dione (Id) and 3,4-dihydro-1-methyl-1H-1,4-benzodiazepin-2,5-dione (Ie) were allowed to react with acetic anhydride under conditions similar to those used for the rearrangement reaction, only acetylation occurred.     

Die 2,6-Diisopropyl-phenylgruppe als sperriger Substituent in Bor-Stickstoff-Verbindungen. II [1]

The 2,6-Diisopropyl-phenyl Group as a Bulky Substituent in Boron-Nitrogen Compounds. II Fluoro-bis(amino)boranes R′ (Me₃Si)N–BF–NHR (R = 2,6-)Me₂CH)₂C₆H₃, R′ = Me ( Ia ), CH₂Me ( Ib ), CHMe₂ ( Ic ), CMe ( Id ), SiMe₃ ( Ie ), R ( If ) react with t-butyllithium (molar ratio 1:1) by elimination of HF to give the amino-imino-boranes ( IIa – f ). The thermal stabilities of the latter depend upon the steric requirement of the substituent R′, IIa – c and IIe dimerize to yield the diazaboretidines IIIa – c and IIIe. IId remains unchanged at 200°C and above, and IIf isomerizes forming the B–Me substituted diazasilaboretidine IVf . If a twofold amount of t-butyllithium is employed, B–CMe₃ substituted diazasilaboretidines ( Va – f ) are the main products. All compounds are characterized by elemental (C, H) analyses and their mass- and n.m.r. (¹H, ¹³C, ¹⁵N (in part), ¹⁹F, ²⁹Si) spectra. Characteristic i.r.-bands are reported for the amino-imino-boranes ( II ). An X-ray structure analysis is presented for IVf .     

Supermesityl-stabilisierte Iminoborane

Supermesityl stabilized Iminoboranes Amino-iminoboranes R′(SiMe₃)N–B≡N–R: IIc (R′ = CHMe₂), IId (R′= CMe₃) and IIe (R′ = SiMe₃) carrying the supermesityl group (R) on the imino nitrogen atoms have been prepared from the corresponding fluorobis(amino)boranes Ic–e by HF-elimination using t-BuLi (IIc, d) or n-lithio-bis(trimethylsilyl)amid (IIe) . The Amino-iminoboranes are thermally stable at room temperature. Upon treatment of the fluorobis(amino)boranes Ia, Ib, Ie with t-BuLi, LiF and HN(SiMe₃)R′ are eliminated and the B-t-butyl substituted iminoborane III is formed. The compounds are characterized by elementar analyses and spectroscopic data (MS, IR, NMR). An X-ray diffraction study has been performed for II d .     

4,4’-[1,n-亚烷基双[(E)-2-(4-氧苯基)乙烯基]]双吡啶的光化学性质(英文)

通过E-[4-[2-（4-羟基苯基）乙烯基]吡啶与1,n-二溴烷烃亲核取代反应合成了4,4’-[1,n-亚烷基双[（E）-2-（4-氧苯基）乙烯基]]双吡啶[n=2（Ia）,3（Ib）,4（Ic）,6（Id）].用元素分析、红外、紫外和质子核磁共振谱鉴定了Ia-Id的结构.将Ia-Id的稀溶液用中压汞灯和低压汞灯交替照射,发现其分子内光环加成反应的存在,并且随着亚烷基碳链的延长,反应速度加快.研究还发现锌离子可以与毗陡环上氮原子发生螯合作用使分子内光环加成反应加快.本文化合物荧光很弱,在较高浓度下有较强分子间激基缔合物荧光.     

4,4′-[1,n-亚烷基双[(E)-2-(4-氧苯基)乙烯基]]双吡啶的光化学性质

通过E-[4-[2-(4-羟基苯基)乙烯基]吡啶与1,n-二溴烷烃亲核取代反应合成了4,4′-[1,n-亚烷基双[(E)-2-(4-氧苯基)乙烯基]]双吡啶[n=2(Ia),3(Ib),4(Ic),6(Id)].用元素分析、红外、紫外和质子核磁共振谱鉴定了Ia～Id的结构.将Ia～Id的稀溶液用中压汞灯和低压汞灯交替照射,发现其分子内光环加成反应的存在,并且随着亚烷基碳链的延长,反应速度加快.研究还发现锌离子可以与吡啶环上氮原子发生螯合作用使分子内光环加成反应加快.本文化合物荧光很弱,在较高浓度下有较强分子间激基缔合物荧光.     

Synthesis and characterisation of mixed ligand Pt(II) and Pt(IV) oxadiazoline complexes

The nitrile ligands in trans-[PtX2(PhCN)2] (X = Cl, Br, I) undergo sequential 1,3 dipolar cycloadditions with nitrones R1R2C=N+(Me)-O(-) (R1 = H, R2 = Ph; R1 = CO2Et, R2 = CH2CO2Et) to selectively form the Delta4-1,2,4-oxadiazoline complexes trans-[PtX2(PhCN) (N=C(Ph)-O-N(Me)-CR1R2)] or trans-[PtX2(N=C(Ph)-O-N(Me)-CR1R2)2] in high yields. The reactivity of the mixed ligand complexes trans-[PtX2(PhCN)(N=C(Ph)-O-N(Me)-CR1R2)] towards oxidation and ligand substitution was studied in more detail. Oxidation with Cl2 or Br2 provides the Pt(IV) species trans-[PtX2Y2(PhCN)(N=C(Ph)-O-N(Me)-CH(Ph))] (X, Y = Cl, Br). The mixed halide complex (X = Cl, Y = Br) undergoes halide scrambling in solution to form trans-[PtX(4-n)Yn(PhCN)(N=C(Ph)-O-N(Me)-CH(Ph))] as a statistical mixture. Ligand substitution in trans-[PtCl2(PhCN)(N=C(Ph)-O-N(Me)-CR1R2)] allows for selective replacement of the coordinated nitrile by nitrogen heterocycles such as pyridine, DMAP or 1-benzyl-2-methylimidazole to produce mixed ligand Pt(II) complexes of the type trans- [PtX2(heterocycle)(N=C(Ph)-O-N(Me)-CR1R2)]. All compounds were characterised by elemental analysis, mass spectrometry, IR and 1H, 13C and 195Pt NMR spectroscopy. Single-crystal X-ray structural analysis of (R,S)-trans-[PtBr2(N=C(Ph)-O-N(Me)-CH(Ph))2] and trans-[PtCl2(C5H5N)(N=C(Ph)-O-N(Me)-CH(Ph))] confirms the molecular structure and the trans configuration of the heterocycles relative to each other.     

Si-disubstituted diallylsilanes in homolytic thiylation and electrophilic fragmentation reactions

Approaches to Si-disubstituted 1-thia-5-silacyclooctanes based on homolytic addition of hydrogen sulfide to diallylsilanes R₂Si(CH₂CH=CH₂)₂ and on intramolecular cyclization of Si-disubstituted (allyl)(γ-sulfanylpropyl)silanes have been studied. In the former case the reactivity of the silanes decreases in the order R = MeO > F > Me > Ph, whereas in the latter case the reactivity order is slightly different: Me > MeO ≈ F ? Ph. The reactions of diphenyl-and dimethyldiallylsilanes with the complex BF₃·2AcOH occur in a different manner: The former involves rearrangement to form fluoro(2-methylpent-4-enyl)diphenylsilane, while the latter, elimination of the two allyl groups to fluorodimethylsilane and propene.     

Synthesis,structure, and reactivity of some N-phosphorylphosphoranimines

A large series of new N-phosphorylphosphoranimines that bear potentially reactive functional groups on both phosphorus centers were prepared by silicon-nitrogen bond cleavage reactions of N-silylphosphoranimines. Thus, treatment of the N-silylphosphoranimines, Me(3)SiN=P(Me)(R)X (R = Me, Ph; X = OCH(2)CF(3) and R = Me, X = OPh), with phosphoryl chlorides, RP(=O)Cl(2) (R' = Cl, Me, Ph), readily afforded the corresponding N-phosphoryl derivatives, R'P(=O)(Cl)-N=P(Me)(R)X, in high yields. Subsequent reaction with 1 or 2 equiv of the silylamine, Me(3)SiNMe(2), resulted in ligand exchange at the phosphoryl (P=O) group to give the P-dimethylamino analogues, R'P(=O)(NMe(2))N=P(Me)(R)X (R' = Cl, NMe(2), Me, Ph; R = Me, Ph; X = OCH(2)CF(3), OPh). These new N-phosphorylphosphoranimines (and one thiophosphoryl analogue) were obtained as thermally stable, distillable liquids and were characterized by NMR ((1)H, (13)C, and (31)P) spectroscopy and elemental analysis. One member of the series, Cl(2)P(=O)N=P(Me)(Ph)OCH(2)CF(3) (4), was also studied by single-crystal X-ray diffraction which revealed that the formal P(O)-N single bond [1.55(1) A] is shorter than the formal N=PR(2)X double bond [1.60(1) A]. Such structural features are compared to those of similar compounds and discussed in relationship to the unexpected thermolysis pathways observed for these N-phosphorylphosphoranimines, none of which produced poly(phosphazenes).     

斯德酮化全物的反应

用3-苄基-4-苯基斯德酮和4-甲酰基-3-芳基斯德酮的硝化研究了在斯德酮环4-取代的去定域化效应和斯德酮环的电子效应的二重性。     

ESR spectroscopic study on the addition of PhCONHCHCO2Me radicals to alkenes and spin traps

Using ESR spectroscopy, the rate constants for the addition of PhCONHCHCO₂Me radicals to alkenes CH₂=CXY (X = Me, Y = Ph; X = H, Y = Ph; X = Me, Y = CO₂Me; X = H, Y = CO₂Me; X = H, Y = CN) and nitrosodurene were determined at 22 °C. It is shown that a linear dependence exists between the donor-acceptor properties of the substituents at the vinyl group and the rate constants for the addition.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 2124–2126, August, 1996.     

Structure and Photochemical Properties of r‐1, c‐2, t‐3, t‐4‐l, 3‐Bis [2‐ (5‐R‐benzoxazolyl) ] −2,4‐di (4‐R' ‐phenyl) cyclobutane

r‐1, c‐2, t‐3, t‐4‐1,3‐Bis[2‐(5‐R‐benzoxazolyl)]‐2,4‐di(4‐R'‐phenyl)cyclobutane (IIa: R=R' = H; IIb: R=Me, R'= H; IIc: R = Me, R' = OMe) was synthesized with high stereo‐selectivity by the photodimerization of trans‐l‐[2‐(5‐R‐benzoxazolyl)]‐2‐(4‐R'‐phenyl) ethene (Ia: R=R' = H; Ib: R = Me, R' = H; Ic: R = Me, R' = OMe) in sulfuric acid. The structures of IIa–IIc were identified by elemental analysis, IR, UV, ¹H NMR, ¹³C NMR and MS. The molecular and crystal structure of IIc has been determined by X‐ray diffraction method. The crystal of IIc (C₃₄H₃₀N₂O₄. 0.5C₂OH) is monoclinic, space group P2₁/n with cell dimensions of a = 1.5416(3), b =0.5625(1), c = 1.7875(4) nm, β = 91.56 (3)°, V= 1.550(1) nm³, Z = 2. The structure shows that the molecule of IIc is centrosymmetric, which indicates that the dimerization process is a head‐to‐tail fashion. The selectivity of the photodimerization of Ia–Ic has been enhanced by using acidic solvent and the reaction speed would be decreased when electron donating group was introduced in the 4‐position of the phenyl group. That the photodimerization is not affected by the presence of oxygen as well as its high stereo‐selectivity demonstrated that the reaction proceeded through an excited singlet state. It was also found that under irradiation of short wavelength UV, these dimers underwent photolysis completely to reproduce its trans‐monomers, and then the new formed species changed into their cis‐isomers through trans‐cis isomerization.     

Heterobimetallic Mo---Sn complexes. Reactions of [Mo(CO)3(CH3CN)2(Cl)(SnRCl2)] (R = Me, Ph) with 4(4-XC6H4)3 (X = Cl, F, H, Me, MeO)

Three families of heterobimetallic compounds were obtained by reaction of [Mo(CO)₃(CH₃CN)₂(Cl)(SnRCl₂)] (R = Ph, Me) with P(4-XC₆H₄)₃ (X = Cl, F, H, Me, MeO). The type of compound obtained dependent on the solvent and concentration of the starting compound. So, [Mo(CO)₂(CH₃COCH₃)₂(PPh₃)(Cl)(SnRCl₂)]·nCH₃COCH₃ (R = Ph, n = 0.5; R = Me, n = 1) (type I) and [Mo(CO)₃{P(4-XC₆H₄)₃}(μ-Cl)(SnRCl₂)]₂ (R = Ph, X = Cl, F, H, Me, MeO; R = Me, X = Cl, F) (type II) were isolated from acetone solution in ca 0.05 M and 0.1 M concentrations, respectively. However, [Mo(CO)₃(CH₃CN) {P(4-XC₆H₄)₃}(Cl)(SnRCl₂)] (R = Ph, X = H; R = Me, X = Cl, F, H) (type III) were obtained from dichloromethane solution independently of the concentration used. All new complexes showed a seven-coordinate environment at molybdenum, containing Mo---Cl and Mo---Sn bonds. Mössbauer spectra indicated a four-coordination at tin for type III complexes.     

5-(2,4-二氯苯氧亚甲基)-2-芳酰胺基-1,3,4-噻二唑的合成

研究了对1-(2,4-二氯苯氧乙酰基)-4-芳酰基氨基硫脲的酸催化环化, 它在酸催化下的环化是定向进行的, 环化途径是生成中间体后脱水而得到5-(2,4-二氯苯氧亚甲基)-2-芳酰胺基-1,3,4-噻二唑, 产物的结构经元素分析, 红外, 核磁以及质谱方法确证。     

Ring transformation of 6-methyl-3,4-dihydro-2H-1,3-oxazine-2,4-diones

Ring transformation of 6-methyl-3,4-dihydro-2H-1,3-oxazine-2,4-dione (Ia) and its N-sub-stituted derivatives, such as 3-methyl (Ib), 3-ethyl (Ic), and 3-benzyl (Id) derivatives is described. Reaction of Ia with hydrazine hydrate gave 1-amino-6-methyluracil (II), while Id reacted with hydrazine hydrate to give 3-hydroxy-5-methylpyrazole (III). Reaction of Ia,b,d with ethyl acetoacetate in ethanol in the presence of sodium ethoxide afforded ethyl 3-acetyl-6-hydroxy-4-methyl-2(1H) pyridone-5-carboxylate derivatives (IVa,b,d). On the other hand, reaction of Ib,c,d with ethyl acetoacetate in tetrahydrofuran in the presence of sodium hydride did not give IV, but gave 3-acetyl-1-alkyl-5-(N-alkylcarbamoyl)-6-hydroxy4-methyl-2(1H) pyridone (VIb,c,d). Mechanisms for the formation of compounds IV and VI are discussed.