Selective transformation reaction of 6,8-dioxabicyclo[3.2.1]octane structure to δ,ε-enone and application to the synthesis of Douglas-fir tussock moth pheromone

Lewis acid induced C-O bond cleavage of a bicyclic ketal compound using AcCl-NaI produced a mixture of δ,ε-enone, allylic acetate and diacetate derivatives via a common 5-membered acetoxonium intermediate. A selective method to the synthesis of δ,ε-enone in high yield was introduced and applied to the synthesis of Douglas-fir tussock moth pheromone.     

Condensed tetracyclic systems with an isatin fragment in the molecule

A new method for the synthesis of the dioxodihydro-1H-benzo[b]furoindole heterocyclic systems from the corresponding isomeric amino acids with the amino groups at positions 2 and 3 is described. By this method it is possible not only to obtain the indicated tetracyclic systems in the form of one isomer but also to interconvert them; from the tetracyclic systems with angular structure it is possible to obtain the corresponding isomers with linear structure and vice versa. The classical Sandmeyer reaction served a model for such transformations. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1314–1321, September, 2007.     

Cross-condensation of derivatives of cyanoacetic acid and carbonyl compounds. 2. One-pot synthesis of substituted 2-amino-7-methyl-5-oxo-4,5-dihydropyrano[4,3-b]pyrans in ethanol and ionic liquid [bmim][PF6]

The three-component reaction of 4-hydroxy-6-methylpyran-2(2H)-one with cyanoacetic acid derivatives and carbonyl compounds in EtOH or in the ionic liquid, viz., 1-butyl-3-methylimidazolinium hexafluorophosphate ([bmim][PF₆]), affords substituted 2-amino-7-methyl-5-oxo-4,5-dihydropyrano[4,3-b]pyrans. The yield of substituted pyrano[4,3-b]pyrans in [bmim][PF₆] is by 10—14% higher than that in EtOH.     

A Divergent Approach to the Diastereoselective Synthesis of 3,3‐Disubstituted Oxindoles from Atropisomeric N‐Aryl Oxindole Derivatives

3,3‐Disubstituted oxindoles were divergently synthesized by diastereoselective transformations including nucleophilic addition, alkylation, and cycloaddition using common, axially chiral N‐aryl oxindoles. Notably, high diastereoselectivities (up to >95:5) were observed with ortho‐monosubstituted N‐aryl oxindoles to give various oxindole scaffolds, and facile removal of the p‐(benzyloxy)aryl moiety in axially twisted amides was achieved by a mild, two‐step sequence.     

三氯化铟高效催化3-(1-吡咯基)吲哚-2-酮类化合物的合成方法

使用三氯化铟在乙醇中回流的条件下催化不同的靛红衍生物与4-羟基脯氨酸反应,以较高的产率(83-99%)和纯度合成得到了相应的产物3-(1-吡咯基)吲哚-2-酮化合物,并对这个反应做了一个比较全面系统的研究.     

A convenient E-diastereoselective synthesisof NH-isatin N′-arylimines via the aza-Wittig reaction

A general synthesis of NH-isatin N′-arylimines involves the aza-Wittig reaction of isatin and aryl azides, providing higher E-diastereoselectivity as compared to previously described methods. The procedure is applicable even to anilines which do not directly react with isatins.     

A novel entry into a new class of spiroheterocyclic framework: regioselective synthesis of dispiro[oxindole-cyclohexanone]pyrrolidines and dispiro[oxindole-hexahydroindazole]pyrrolidines

2,6-Bis(arylmethylidene)cyclohexanones undergo a regioselective 1,3-dipolar cycloaddition reaction with the azomethine ylide derived from isatin and sarcosine by a decarboxylative route affording a series of 1-N-methyl-spiro[2.3¹]oxindole-spiro[3.2¹¹]6¹¹-arylmethylidenecyclohexanone-4-aryl-pyrrolidines which were further annulated to give a series of novel 1-N-methyl-spiro[2.3¹]oxindole-spiro[3.7¹¹](3¹¹-aryl)Δ^111,711a-hexahydro-2H-indazole-4-aryl-pyrrolidines. The structures of which were established by spectroscopic techniques as well as single crystal X-ray analysis.     

掺杂La2O3的硫酸钛在缩醛(酮)反应中的催化活性

硫酸钛掺杂La2O3后经高温焙烧制得一种新型固体酸催化剂。用环己酮缩乙二醇反应表征其催化活性的反应条件为：环己酮200mmol,n(环己酮)：n(乙二醇)=1．0：1．5,带水剂环己烷15mL,硫酸钛催化剂[w(La2O3)0．05,400℃焙烧3h]用量4．1％(以环己酮质量计),回流分水1h,收率94．5％。结果表明,催化活性随La2O3含量的增加而升高,随焙烧温度的升高而降低。催化剂吸附吡啶的红外光谱证实催化剂表面存在明显的Broensted酸中心和Lewis酸中心。该催化剂对其它缩醛(酮)反应也有催化活性。     

H4 SiW12 O40 /C催化合成丁酮1,2-丙二醇缩酮

以丁酮和1,2-丙二醇为原料,活性炭负载硅钨酸（H4SiW12O40／C）为催化剂,催化合成了丁酮1,2-丙二醇缩酮。正交试验筛选出最佳反应条件为：丁酮200mmol,n（丁酮）：n（1,2-丙二醇）=1．0：1．4,ω（催化剂）=1．2％（以反应物质量计）,反应时间1h。在此最佳反应条件下,丁酮1,2-丙二醇缩酮的收率可达71．13％。     

Water-Promoted Synthesis of 3,3′-Di(indolyl)oxindoles

The reaction of isatin and indoles in refluxing water/ethanol (7:3) affords 3,3′-di(indolyl)oxindoles in excellent yields.