Synthesis and reactivity of allenes substituted by selenenyl groups at 1- and 3-positions

1,3-Bis(methylseleno)- and 1,3-bis(benzylseleno)-1,3-diphenylpropadienes were synthesized by reaction of Ph(2)C(3) dianion, prepared from 1,3-diphenylpropyne and n-butyllithium, with dimethyl diselenide or benzylselenocyanate in the presence of TMEDA, and reaction of the dianion with a mixture of dimethyl diselenide and benzylselenocyanate yielded 1-benzylseleno-3-methylselenoallene along with the symmetric allenes. Diselenocyclic allenes and tetraselenocyclic bisallenes were also obtained by reacting the dianion with corresponding alkane diselenocyanates. The thermal reaction of the 1,3-bis(alkylseleno)allenes mainly afforded enediynes through radical pathway, and the nine-membered cyclic allene provided intramolecular cyclization product via an intramolecular rearrangement. Heating of the cyclic bisallenes gave compounds derived from intramolecular cyclization products together with a small amount of the enediynes. Irradiation of allenes caused rearrangement of the selenenyl group to give alkynes, and the alkynes also reacted photochemically to yield the enediynes.     

新型双子表面活性剂在H2S和CO2盐水溶液中对碳钢的缓蚀性能

合成了一系列含有羟基的双子表面活性剂:1,3-双(十二烷基二甲基氯化铵)-2-丙醇(12-3OH-12),1,3-双(十四烷基二甲基氯化铵)-2-丙醇(14-3OH-14),1,3-双(十六烷基二甲基氯化铵)-2-丙醇(16-3OH-16)和1,3-双(十八烷基二甲基氯化铵)-2-丙醇(18-3OH-18).采用静态失重法、极化曲线和交流阻抗技术研究了其在H2S/CO2腐蚀环境中对L360钢的缓蚀作用.结果表明,三种研究方法取得的结论是一致的,缓蚀效果为14-3OH-14>12-3OH-12>16-3OH-16>18-3OH-18.其中,12-3OH-12和14-3OH-14都表现出很好的缓蚀效果,在35mg·L-1的较低浓度下缓蚀率就达95%以上.极化曲线测试结果表明n-3OH-n(n=12,14,16,18)型双子表面活性剂是一种以阳极抑制为主的混合型缓蚀剂.除n=18外,其它三种双子表面活性剂n-3OH-n(n=12,14,16)在L360钢表面的吸附服从朗缪尔等温线,并且属于物理和化学混合吸附.提出了一个用来解释双子表面活性剂在H2S/CO2溶液中缓蚀机理的吸附模型.     

Chemo-, regio-, and stereoselective cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with alpha-chloroacetic acid chlorides and alpha-chloroacetic acetals

Treatment of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with alpha-chlorocarboxylic acid chlorides resulted in chemo- and regioselective formation of 6-chloro3,5-dioxo esters, which were regioselectively converted into functionalised 3(2H)furanones. Chemo- and regioselective condensation of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with alpha-chloroacetic dimethyl acetal afforded 6-chloro-5-methoxy-3-oxo esters, which could be regio- and stereoselectively transformed into 2-alkylidene-4-methoxytetrahydrofurans.     

Synthesis of 3,4-Bis(Butylselanyl)Selenophenes and 4-Alkoxyselenophenes Promoted by Oxone®

We describe herein an alternative transition-metal-free procedure to access 3,4-bis(butylselanyl)selenophenes and the so far unprecedented 3-(butylselanyl)-4-alkoxyselenophenes. The protocol involves the 5-endo-dig electrophilic cyclization of 1,3-diynes promoted by electrophilic organoselenium species, generated in situ through the oxidative cleavage of the Se-Se bond of dibutyl diselenide using Oxone^® as a green oxidant. The selective formation of the title products was achieved by controlling the solvent identity and the amount of dibutyl diselenide. By using 4.0 equiv of dibutyl diselenide and acetonitrile as solvent at 80 °C, four examples of 3,4-bis(butylselanyl)selenophenes were obtained in moderate to good yields (40–78%). When 3.0 equiv of dibutyl diselenide were used, in the presence of aliphatic alcohols as solvent/nucleophiles under reflux, 10 3-(butylselanyl)-4-alkoxyselenophenes were selectively obtained in low to good yields (15–80%).     

Investigation of reactions of the organozinc reagents prepared from zinc and dialkyl dibromomalonates with the derivatives of 2-arylmethyleneindan-1,3-dione and 5-arylmethylene-2,2-dimethyl-1,3-dioxane-4,6-dione

Organozinc compounds prepared from dialkyl dibromomalonates and zinc react with 2-arylmethyl-eneindan-4,6-diones, 5-arylmethylene-2,2-dimethyl-1,3-dioxane-4,6-diones, as well as with 2-[4-(1,3-dioxoindan-2-ylidenemethyl)phenyl]methyleneindan-1,3-dione and 5-[4-(2,2-dimethyl-4,6-dioxo-1,3-dioxane-2-ylidenemethyl)phenyl]methylene-2,2-dimethyl-1,3-dioxane-4,6-diones to form dialkyl 3-aryl-1′3′-dioxaspiro(cyclopropane-2,2′-indan)-1,1-dicarboxylates, dimethyl 3-aryl-6,6-dimethyl-5,7-dioxa-4,8-dioxaspiro[2,5]octan-2,2-dicarboxylates, dialkyl 2-{4-[3,3-bis (alkoxycarbonyl)-1′,3′-dioxaspiro(cyclopropane-2,2′-indan)-1-yl]phenyl}-1′,3′-dioxaspiro[cyclopropane-2,2′-indan]-1,1-dicarboxylates, and dialkyl 2-{4-[2,2-bis(alkoxycarbonyl)-6,6′-dimethyl-4,8-dioxo-5,7-dioxaspiro[2,5]oct-1-yl]phenyl}-6,6-dimethyl-4,8-dioxo-5,7-dioxaspiro[2,5]octan-1,1-dicarboxylate respectively.     

Reaction of dimethylphosphorous acid with 2,5-bis(carbomethoxy)-3,4-diphenylcyclopentadienone

Conclusions The reaction of 2,5-bis(carbomethoxy)-3,4-diphenylcyclopentadienone with dimethyl phosphite, both in the presence of Et₃N and in the absence of catalysts, goes with the formation of the dimethyl esters of 2-oxo-4,5-diphenyl-1,3-dicarbomethoxy-4-cyclopentene- and 2-oxo-4,5-diphenyl-1,3-dicarbomethoxy-3-cyclopentene-1-phosphonic acids. In contrast to alcohols and primary amines, dimethyl phosphite does not form the 1,4-addition products with this acceptor.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1119–1125, May, 1980.     

Synthesis of 4-hydroxy- and 2,4-dihydroxy-homophthalates by [4+2] cycloaddition of 1,3-bis(silyloxy)-1,3-butadienes with dimethyl allene-1,3-dicarboxylate

The reaction of 1,3-bis(trimethylsiloxy)-1,3-butadienes with dimethyl allene-1,3-dicarboxylate provides a convenient and regioselective approach to a variety of functionalized 4-hydroxy- and 2,4-dihydroxy-homophthalates.     

Manganese(III)-mediated intermolecular cyclization reactions of alkenes and active methylene compounds

The reactions of 1,1-diphenylethene, 1,1-bis(4-chlorophenyl)ethene, 1,1-bis(4-methylphenyl)ethene, and 1,1-bis(4-methoxyphenyl)ethene with 3,5-diacetyl-2,6-heptanedione in the presence of manganese(III) acetate in acetic acid at 80° yielded 4,6-diacetyl-8,8-diaryl-1,3-dimethyl-2,9-dioxabicyclo[4.3.0]non-3-enes (41-48%), 5-acetyl-2,2-diaryl-6-methyl-2,3-dihydrobenzo[b]furans (20–21%), 3-acetyl-5,5-diaryl-2-methyl-4,5-dihydrofurans (5–10%), and benzophenones (3–7%). Similarly, the reactions of 1,1-diarylethenes with dimethyl 2,4-diacetyl-1,5-pentanedioate or diethyl 2,4-diacetyl-1,5-pentanedioate gave the corresponding 4,6-bis(alkoxycarbonyl)-8,8-diaryl-1,3-dimethyl-2,9-dioxabicyclo[4.3.0]non-3-enes in moderate yields.     

4,5-Dimethylene -1,2-dioxane and derived Diels-Alder adducts

4,5-Dimethylene-1,2-dioxane (1) was prepared by zinc-induced debromination of 4,5-bis (bromomethyl)-1,2-dioxacylohexa-4-en (4) obtained from 2,3-bis (bromomethyl-1,3-butadiene (3) by reaction with singlet oxygen. Diels-Alder additions of 1 with singlet oxygen, dimethyl acetylenedicarboxylate and N-methyl-1,2,4-triazoline-3,5-dione gave adducts 2,6 and 8 respectively. 3,4-Disubtituted furans 5 and 9 were obtained from peroxides 4 and 8 by cobalt (II) tetraphenylporphyrin catalyzed rearrangement.     

Synthesis of 3,5-diaryl-4-chlorophthalates by [4+2] cycloaddition of 1-ethoxy-2-chloro-1,3-bis(trimethylsilyloxy)-1,3-diene with dimethyl acetylenedicarboxylate and subsequent site-selective Suzuki-Miyaura reactions

The [4+2] cycloaddition of 1-ethoxy-2-chloro-1,3-bis(trimethylsilyloxy)-1,3-diene with dimethyl acetylenedicarboxylate (DMAD) afforded dimethyl 4-chloro-3,5-dihydroxyphthalate. Site-selective Suzuki-Miyaura reactions of its bis(triflate) provide a convenient approach to 3,5-diaryl-4-chlorophthalates containing two different aryl groups.     

Synthesis of 1,3-bis[(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dienylidene)(dimethoxyphosphoryl)methyl]-4,6-dimethoxybenzene

A reaction of 1,3-dimethoxybenzene with dimethyl (3,5-di-tert-butyl-4-oxocyclohexa-2,5-dienylidenemethyl)phosphonate gave rise to 1,3-bis[(3,5-di-tert-butyl-4-hydroxyphenyl)-(dimethoxyphosphoryl)methyl]-4,6-dimethoxybenzene, which was oxidized to 1,3-bis[(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dienylidene)(dimethoxyphosphoryl)methyl]-4,6-dimethoxy-benzene.     

Borohydride reduction of acetophenone and esters of dehydrocarboxylic acids in the presence of chiral cobalt(<Emphasis Type="SmallCaps">II</Emphasis>) diamine complexes

The catalytic reduction of acetophenone, methyl α-acetamidocinnamate, and dimethyl itaconate with alcohol-modified sodium borohydride was studied in the presence of complexes CoCl₂·L₂ (L₂ are chiral C ₂-symmetric diamines: (4S,5S)-2,2-dimethyl-4,5-bis(aminomethyl)-1,3-dioxolane, (4S, 5S)-2,2-dimethyl-4,5-bis(methylaminomethyl)-1,3-dioxolane, (4S, 5S)-2,2-dimethyl-4,5-bis(dimethylaminomethyl)-1,3-dioxolane, and (4S, 5S)-2,2-dimethyl-4,5-bis(diphenylaminomethyl)-1,3-dioxolane). The maximum enantiomeric excess of (S)-1-phenylethanol was 24%, that of dimethyl α-methylsuccinate was 38%.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 342–347, February, 2005.     

Unusual reaction of 3-amino-1,2,4-triazole with 1,3-diiodopropan-2-one

3-Amino-1,4-bis(2-oxopropyl)-4H-1,2,4-triazolium triiodide is the product of the reaction of 3-amino-1,2,4-triazole with 1,3-diiodopropan-2-one in acetone in the absence of bases and phase-transfer catalysts. In dimethyl sulfoxide, conversely, a water soluble polyionene consisting of three aminotriazole rings bound by 1,3-dimethylenecarbonyl bridges is formed. The effect of the solvent on the alkylation of 3-amino-1,2,4-triazole with 1,3-diiodopropan-2-one was studied.     

Distinguishing conventional and distonic radical cations by using dimethyl diselenide

Dimethyl diselenide is demonstrated to be among the most powerful reagents used to identify distonic radical cations. Most such ions readily abstract CH₃Se^. from dimethyl diselenide. The reaction is faster and more exclusive than CH₃S^. abstraction from dimethyl disulfide, a reaction used successfully in the past to identify numerous distonic ions. Very acidic distonic ions, such as HC⁺(OH)OCH^.₂, do not undergo CH₃Se^. abstraction, but instead protonate dimethyl diselenide. In sharp contrast to the reactivity of distonic ions, most conventional radical cations were found either to react by exclusive electron transfer or to be unreactive toward dimethyl diselenide. Hence, this reagent allows distinction of distonic and conventional isomers, which was demonstrated directly by examining two such isomer pairs. To be able to predict whether electron transfer is exothermic (and hence likely to occur), the ionization energy of dimethyl diselenide was determined by bracketing experiments. The low value obtained (7.9 ± 0.1 eV) indicates that dimethyl diselenide will react with many conventional carbon-, sulfur-, and oxygen-containing radical cations by electron transfer. Nitrogen-containing conventional radical cations were found either to react with dimethyl diselenide by electron transfer or to be unreactive.     

Alkylation of 2-methylimidazole with iodomethylsilanes

2-Methyl-1,3-bis[(1-methylsilolan-1-yl)methyl]-1H-imidazolium triiodide, 1,3-bis{[dimethyl-(phenyl)silyl]methyl}-2-methyl-1H-imidazolium iodide and triiodide, and cyclic 3,3,5,5,10-pentamethyl-4-oxa-7-aza-1-azonia-3,5-disilabicyclo[5.2.1]deca-1(10),8-diene iodide were synthesized by solvent-free reactions of 2-methyl-1H-imidazole with 1-(iodomethyl)-1-methylsilolane, (iodomethyl)(dimethyl)phenylsilane, and ethynyl(iodomethyl)(dimethyl)silanes, respectively, in the absence of base catalyst.     

Electrophilic substitution reactions of indole alkaloids with α,β-unsaturated carbonyl compounds in the presence of K10 montmorillonite

Reactions of indole, 1-methylindole, and 3-methylindole with dimethyl acetylenedicarboxylate in the presence of K10 montmorillonite as a catalyst led to the formation of the corresponding dimethyl 2,2-bis(indolyl)butanedioates. The reaction of 2-methylindole with dimethyl acetylenedicarboxylate gave dimethyl 2-(2-methyl-1H-indol-3-yl)maleate and dimethyl 2-methyl-1H-1-benzoazepine-3,4-dicarboxylate. Dimethyl 1,5-dimethyl-1H-1-benzoazepine-3,4-dicarboxylate was obtained by treatment of 1,3-dimethylindole with dimethyl acetylenedicarboxylate using K10 clay as a catalyst. Published in Russian in Zhurnal Organicheskoi Khimii, 2006, Vol. 42, No. 6, pp. 900–902. The text was submitted by the authors in English.     

Synthesis of Macrocyclic Pyrimidine Derivatives

A reaction was studied of previously unknown 1,3-bis(2-hydroxy-3-chloropropyl)uracil, 1,3-bis(2- hydroxy-3-chloropropyl)-6-methyluracil, and 1,3-bis(2-hydroxy-3-chloropropyl)-5-fluorouracil with 1,3-bis[3-(3-methyl-2H-5-pyrazolon-1-yl)-2-hydroxypropyl]-6-methyluracil.     

Synthesis of 2-(1,5,9-Triazabicyclo[7.3.1]tridec-10-en-5-yl)-4-methylthiobutanoic Acid Derivatives

Reactions of 1,3-bis(3-chloro-2-hydroxypropyl)uracil, 1,3-bis(3-chloro-2-hydroxypropyl)-6-methyluracil, 1,3-bis(3-chloro-2-hydroxypropyl)-5-hydroxy-6-methyluracil, and 1,3-bis(3-chloro-2-hydroxypropyl)-5-fluorouracil with 2-amino-4-methylthiobutanoic acid (methionine) were studied for the first time.     

A synthesis of lumazine derivatives

Treatment of 6-amino-1,3-dimethyl-5-nitrosouracil (Ia) with dimethyl acetylenedicarboxylate (DMAD) in dimethylformamide (DMF) afforded 6,7-bis(dimethoxycarbonyl)-1,3-dimethyllumazine (II). Similarly, the reaction of 6-amino-1,3-dimethyl-5-phenylazouracil with DMAD gave also II. Hydrolysis of II with hydrochloric acid gave 1,3-dimethyllumazine-6-carboxylic acid (III). III was chlorinated with thionyl chloride and then aminated with ethanolic ammonia to give rise to 6-carbamoyl-1,3-dimethyllumazine (V). V was alternatively synthesized by the treatment of Ia with propiolamide in DMF.     

Synthesis of some new nitrogen bridge-head pyrido[1,2,4]triazepines

Ring closure reactions of 1,6-diamino-4-(4-chlorophenyl)-2-oxopyridine-3,5-dicarbonitrile with various 1,3-dielectrophiles, namely, diethyl malonate, ethyl ethoxymethylenecyanoacetate, 2-cyano-3,3-bis(methylthio)acrylonitrile, dimethyl acetylenedicarboxylate, dehydroacetic acid, chromone-3-carbonitrile, and 3-formylchromone led to the formation of the target biheterocyclic 1,2,4-triaze-pines. The reactions with 3-phenylazo-2,4-pentadione, ethyl α-cyano-α-phenylazoacetate, and 3,1-benz-oxazin-4-one derivative are also described.