Condensation of Ethyl 2-Oxoindoline-3-glyoxylate with o-Aminophenol and o-Phenylenediamine

A method is presented for the synthesis of 3-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-1,4-dihydroquinoxalin-2-one and 2-(2-oxo-1,2-dihydro-3H-indol-3-ylidene)-2H-1,4-benzoxazin-3(4H)-one by the reaction of ethyl 2-oxoindoline-2-glyoxylate with o-aminophenol and o-phenylenediamine. Proposed reaction mechanisms are presented.     

Novel synthesis of 1,4-thiazin-2-one O-(tert-butyl) oximes and benzo[b][1,4]thiazin-2-one O-(tert-butyl) oximes in the presence of K2CO3/SiO2

A simple and efficient method was developed for the synthesis of 1,4-thiazin-2-one O-(tert-butyl) oximes and benzo[b][1,4]thiazin-2-one O-(tert-butyl) oximes from N-tert-butoxy acyl imidoyl bromides and 2-aminothiols in the presence of K₂CO₃/SiO₂. Twenty five novel compounds were readily synthesized in excellent yields using this procedure. The products possessed Z-stereochemistry with regard to the CN double bond. The reaction proceeded with initial substitution of bromine in the N-tert-butoxy acyl imidoyl bromides by mercapto groups in the presence of K₂CO₃/SiO₂, and subsequent intramolecular Schiff base formation.     

Ring-opening polymerization of 1,4-oxathian-2-one and its copolymerization with δ-valerolactone

Monomer 1,4-oxathian-2-one ( OX ) was synthesized by a one pot two-step method, and it was oxidized to the sulfone ester monomer, 1,4-oxathian-2-one-4,4-dioxide ( OX-SO ₂ ). Three organic catalysts, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and diphenyl phosphate (DPP) were screened for the ring-opening polymerization (ROP) of OX in dichloromethane at 30°C. It was found that OX has a high polymerizability, the TBD-catalyzed ROP is very fast but with serious side reactions, the DBU-catalyzed ROP is moderately controlled, and the DPP-catalyzed ROP is well controlled until the polymerization reach equilibrium. Bulk ROP of OX-SO ₂ was achieved with stannous octoate ((Sn[Oct]₂) at 130°C. Poly(OX) is a semicrystalline polyester (T_m = 40-60°C, T_g = −39.6°C), while Poly(OX-SO ₂ ) is a highly crystalline polyester(T_g = 55°C, T_m = 211°C with decomposition). Kinetics experiments of OX and δ-valerolactone (VL) revealed that VL polymerized faster than OX with DPP as the catalyst. Thermodynamic parameters of the ROP of OX and VL under identical conditions were measured; the ROP of OX is thermodynamically more favorable than that of VL. A series of random copolymers of OX and VL was prepared using TBD as the catalyst and confirmed that the in-chain heteroatom greatly affected the crystallization of the copolymers.     

Synthesis of poly(1,4-dioxan-2-one-co-trimethylene carbonate) for application in drug delivery systems

Poly(1,4-dioxan-2-one-co-trimethylene carbonate), P(DON-co-TMC), copolymers with different compositions were synthesized by copolymerizations of 1,4-dioxan-2-one (DON) and trimethylene carbonate (TMC) at 120°C in the presence of Sn(Oct)₂. Their structures and compositions were determined with FT-IR and ¹H-NMR spectroscopies. The intrinsic viscosities of copolymers increased with the increase of the TMC fraction in feed. The DSC results of copolymers showed that the glass transition temperatures (T_gs) of copolymers are lower than those of homopolymers. Most copolymers are amorphous except for one with a high DON composition. The hydrophilicity of the copolymers is in proportion with the DON molar fraction in the copolymers. It was found that the Levonorgestrel (LNG) release rate is dependent of the composition and flexibility of polymer chains. The fastest one is the copolymer with nearly a equivalent fraction of DON to TMC. Among copolymers with other compositions, a higher DON fraction would be favorable to the release of LNG. All measurements demonstrate an almost constant release rate in the period of 1 month. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1301–1307, 1998     

A new synthesis of 3-hydroxy-2,3-dihydro-1,4-benzodioxin-2-carboxamides and 3-aminomethylene-1,4-benzodioxin-2(3H)-one derivatives

The 1,4-benzodioxin-2-carboxylic esters or carboxamides react with nucleophilic amines to give access to 3-hydroxy-2,3-dihydro-1,4-benzodioxin-2-carboxamides and 3-aminomethyn-1,4-benzodioxin-2(3H)-one precursors of potential therapeutical compounds. The basic environment (K₂CO₃ or amine) facilitates the process.     

Synthesis of 2-Benzylidene and 2-Hetarylmethyl Derivatives of 2H-1,4-Benzoxazin-3-(4H)-ones as Neuroprotecting Agents

A wide variety of the title compounds were synthesized by conventional and microwave methods in which the main step is a condensation of an aldehyde with a 1,4-benzoxazin-3-(4H)-one. In all cases, the Z diasteromers were the major products. Of particular importance is the synthesis of novel 2-(3,5-dibromo-4-hydroxy) and 2-(4-acetoxy-3,5-dibromobenzylidene derivatives of 2H-1,4-benzoxazin-3-(4H)-ones, four of which were shown in a previous publication to exhibit potent neuroprotecting properties. The yields of titled compounds ranged from 25 to 83%.     

Three-component condensation of pyridin-2-one, bis(2-chloroethyl)amine hydrochloride, and K2CO3 in DMF as a new method for oxazolidinylethylation

Three-component condensation of pyridin-2-one, bis(2-chloroethyl)amine hydrochloride, and K₂CO₃ in DMF unexpectedly gave N-and O-oxazolidinylethylation products of pyridin-2-one in the ratio 3: 2. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1047–1048, May, 2007.     

(±)-2,3,5-trichloro-4,4-ethylenedioxycyclopent-2-en-1-one and its 5-allyl-substituted derivative in conjugated 1,4-addition with dimethyldilithium cyanocuprate

(±)-2,3,5-Trichloro-4,4-ethylenedioxycyclopent-2-en-1-one reacts with Me₂CuCNLi₂ to give depending on conditions the corresponding 3-methyl substituted cyclopentenone (Ad _N E adduct) or a mixture of unsaturated acyclic acids formed as the result of abnormal cleavage reaction of C(1)−C(2) bond in the trichorocyclopentenone. Reactions of conjugated 1,4-addition of Me₂CuCNLi₂ to (±)-5-allyl-2,3,5-trichloto-4,4-dimethoxycyclopent-2-en-1-one lead to products of replacement of vinylic Cl atom at C(3) by Me group and those of C(5)-dechlorination. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1990–1994, November, 1997.     

Control of electron demand in the cycloadditions of 2(H)-1,4-oxazin-2-ones

3-Methoxy-5-chloro-6-methyl-2(H)-1,4-oxazin-2-one 4, 3-methoxy-5-chloro-6-phenyl-2(H)-1,4-oxazin-2-one 5, 3-phenylsulfenyl-5-chloro-6-methyl-2(H)-1,4-oxazin-2-one 6, and 3-phenylsulfenyl-5-chloro-6-phenyl-2(H)-1,4-oxazin-2-one 7, are ambident dienes and undergo Diels-Alder cycloadditions with electron neutral, rich and deficient dienophiles.     

An unexpected skeletal transformation of 1,4-dihydroxythioxanthen-9-one on treatment with iodic acid: the first construction of the 2-(5-oxofuran-2-ylidene)-1-benzothienyl-3-one core

Treatment of 1,4-dihydroxythioxanthen-9-one with iodic acid gives, depending on the reaction conditions, predominantly either thioxanthen-1,4,9-trione or, unexpectedly, 2-(5-oxofuran-2(5H)-yliden)-1-benzothienyl-3(2H)-one. The latter is obtained in 60% yield.     

A Novel and Efficient Reaction of Imidazolidin-2-one and N-Acylbenzotriazoles: A Facile Synthesis of 1-Acylimidazolidin-2-one

Acylation of imidazolidin-2-one with readily available N-acylbenzotriazoles, in the presence of K₂CO₃, produced 1-acylimidazolidin-2-ones and N,N′-diacyl-imidazolidin-2-one in moderate to good yields. The utilization of N-acylbenzotriazoles which make the reaction simple and mild, may be especially advantageous when the corresponding acid chlorides are not stable or not easily prepared. It's also an example of the reaction of N-acylbenzotriazoles and amide.     

A facile and efficient approach for the synthesis of 3-arylthiazol-2(3H)-one

A facile and efficient method for synthesis of 3-arylthiazol-2(3H)-one through the reaction of acyl azide and 1,4-dithiane-2,5-diol was reported. This reaction proceeded at 80?°C at first and then in acidic condition at room temperature, to afford products in good yields for a wide range of substrates and a possible mechanism has also been proposed.     

虾青素的合成

以α-紫罗兰酮为起始原料, 采用2C₁₅＋C₁₀→C₄₀路线合成了虾青素. 并经过选择性环氧化三甲基硅基烯醇醚双键的关键步骤, 设计并完成了关键中间体C₁₅部分——6-羟基-3-(3-羟基-3-甲基-1,4-戊二烯)-2,4,4-三甲基-2-环己烯-1-酮的合成.     

Electrocarboxylation of 1,4-dibromobut-2-ene in a CO2-DMF liquid mixture

The possibility of synthesizing dihydromuconic acid by cathodic carboxylation of 1,4-dibromobut-2-ene in the liquid CO₂-aprotic solvent system was investigated. The low yield of dihydromuconic acid in this reaction was explained by the competing reductive debromodimerization and oligomerization of 1,4-dibromobut-2-ene, which lead to the predominant formation of 1,8-dibromo-2,6-octadiene and polymeric products. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1637–1641, September, 1997.     

Novel access to 1,4-benzodiazepin-2-ones via the Buchwald reaction and application to the synthesis of novel heterocyclics

A new two step strategy for the preparation of 1,4-benzodiazepin-2-ones has been developed starting from the 2-halogenobenzophenone under Buchwald conditions (Pd(OAc)₂, XantPhos, Cs₂CO₃, dioxane 100 °C). This strategy has been extended to two 2-halogeno-3-benzoyl-azines (pyridines, pyridazines).     

The synthesis of benzophenothiazine derivatives

Summary The reaction of substituted 1,4-naphthoquinones with 2-aminothiophenol ando-aminoheterocyclic thiones in acidic condition afforded benzophenothiazin-5-one and azabenzophenothiazin-5-one derivatives, respectively.

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Die Synthese von Benzophenothiazin-Derivaten

Zusammenfassung Die Reaktion von substituierten 1,4-Naphthochinonen mit 2-Aminophenol bzw.o-aminoheterocyclischen Thionen führte unter sauren Bedingungen zu Benzophenothiazin-5-onen bzw. Azabenzophenothiazin-5-onen.

     

Synthesis and efficiency of photolysis of methylated 2-dialkylamino- and 2-piperidino-1,4-naphthoquinones

2-Dialkylamino- and 2-piperidino-1,4-naphthoquinones with a methyl group in position 3 or 5(8) of the naphthoquinone were synthesized by reacting dimethyl- and diethylamines and piperidine with 2- and 5-methyl-1,4-naphthoquinones. The quantum yields of photoconversion of the synthesized compounds in benzene were determined. A 1.2- to 6.5-fold increase of the quantum yield over that of 2-dimethylamino-1,4-naphthoquinone was established. A comparison of the quantum yields with the calculated charges on the reaction centers in the excited (T ₁) state showed that there is not a linear relationship between them.Institute of Organic Chemistry, Russian Academy of Sciences, Siberian Branch, 630090 Novosibirsk. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 3, pp. 707–714, March, 1992.     

Synthesis of annelated derivatives of tetrafluoro-10<Emphasis Type="Italic">H</Emphasis>-imidazo[1,2-<Emphasis Type="Italic">b</Emphasis>][1,2]benzooxazin-10-one and 2-pentafluorophenylpyrazine 1,4-dioxide by condensation of alicyclic 2-hydroxyamino oximes with pentafluorophenylglyoxal

Reactions of alicyclic 2-hydroxyamino oximes with pentafluorophenylglyoxal afford mixtures of annelated derivatives of 2-pentafluorophenylpyrazine 1,4-dioxide and tetrafluoro- 10H-imidazo[1,2-b][1,2]benzooxazin-10-one. The structures of the latter were established by X-ray diffraction analysis.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1636–1639, August, 2004.     

烃基硅铜酸盐与2-芳基-2-环烯酮1,4-加成反应的立体选择性及2-取代- 3-硅基环烷酮的合成

研究了烷基苯基硅铜酸盐与2-环烯酮的1,4-加成反应的立体选择性, 并合成了一系列新的2-取代-3-硅基环烷酮. 结果表明, 在0 ℃下用饱和NH₄Cl溶液处理, 烷基苯基硅铜酸盐与2-芳基-2-环烯酮的1,4-加成反应的立体选择性不同程度地受芳基和环的大小影响, 得到顺、反两种产物; 并首次发现室温下用甲醇处理反应时, 其立体选择性不受或者很少受环大小、芳基的性质以及与硅原子相连的取代基的影响, 只得到反式产物. 芳基溴甲烷与由烷基苯基硅铜酸盐与2-环烯酮1,4-加成所得的烯醇盐反应时, 只得到反式产物. 合成产物的结构用IR, ¹H NMR, ¹³C NMR, MS和HRMS等进行了表征.     

Synthesis of 4-nitromethylene-1,4-dihydropyrimidine derivatives as pyrimidine nucleoside analogues

The synthesis of 4-nitromethylene-1,4-dihydropyrimidine derivatives as pyrimidine nucleoside analogues was developed, starting from 3-nitropyran-2-one N-functionalized amidines. Primary amines were reacted with amidines yielding 4-nitromethylene-1,4-dihydropyrimidine derivatives. In an initial survey, several 4-nitromethylene-1,4-dihydropyrimidines turned into 4-nitromethylene-1,2,3,4-tetrahydropyrimidine derivatives under different reduction conditions. The reduction reaction also induced a change in the exocyclic double bond configuration from (E) to (Z), due to an intramolecular hydrogen bond.