Syntheses of the tedanolides and myriaporones

This review covers the synthetic contributions leading to the syntheses of the polyketides tedanolide, 13-deoxytedanolide and the structurally related myriaporones. Fragment syntheses that lead to valuable insight into the subtle synthetic problems of the tedanolides are also presented.     

Synthesis of the C1-C12 fragment of the tedanolides. Aldol-non-aldol aldol approach

The combination of highly stereoselective non-aldol aldol and aldol processes allows the preparation of the completely protected C1-C12 fragment 2 of the novel macrocyclic cytotoxic agent tedanolide 1.     

Anti aldol selectivity in a synthetic approach to the C1-C12 fragment of the tedanolides

In a synthetic approach to the completely protected C1-C12 fragment of the macrocyclic cytotoxic agent tedanolide 1, we carried out the tin-catalyzed Mukaiyama aldol reaction between the 2,3-dialkoxypropanal 5 and the silyl enol ether 6 derived from the ketone 7, which gave, unexpectedly, the anti aldol isomer, rather than the expected syn isomer 4, as the major diastereomer formed.     

Syntheses of the cylindrospermopsin alkaloids

An intramolecular 1,3-dipolar cycloaddition has efficiently constructed the A-ring portions of the cylindrospermopsin alkaloids. A nitro-aldol addition of an elaborated nitroalkane to a pyrimidine aldehyde followed by an intramolecular reductive guanidinylation has enabled the syntheses of all three alkaloids in this family in 18-19 steps. We report the first asymmetric synthesis of cylindrospermopsin, unambiguously assigning its absolute configuration.     

某些氮杂环烷衍生物的合成

多氮杂环多羧酸及其氮取代化合物因其特殊的螯合能力近年来得到了日益广泛的研究,多氮杂环烷多乙酸的合成及其应用研究报道较多[1～3],而多氮杂环多丙酸及氮上带3个碳原子以上取代基的化合物研究较少,随着氮原子上碳链的增长,此类化合物作为配体其硬度下降,有助于分离某些金属离子.我们以Cyelen.4HCl及Cyclam为原料以LiOH为碱在水溶液中与氯丙酸反应合成了化合物Ⅰ,Ⅱ,用Cyclen和Cyclam为原料与丙烯腈回流合成了化合物Ⅲ,Ⅳ.     

Synthesis of the C1-C12 fragment of the tedanolides. Selective hydroboration-protonation of allylic alcohol approach

The combination of highly stereoselective vinyllithium addition and hydroboration-protonation of the resulting allylic alcohol permits the preparation of the completely protected C₁-C₁₂ fragment 2 of the novel macrocyclic cytotoxic agent tedanolide 1.     

Efficient synthesis of the C(1)-C(11) fragment of the tedanolides. The nonaldol aldol process in synthesis

[reaction: see text] The nonaldol aldol process developed in our laboratories has been applied to the synthesis of a C(1)-C(11) fragment 22 of the novel macrocyclic cytotoxic agents tedanolide and 13-deoxytedanolide 1 and 2. The commercially available hydroxy ester 7 was converted in 24 steps into compound 22 using two nonaldol aldol reactions.     

Syntheses in the quinoline series

2-Formyl-8-hydroxyquinoline and 5,7-dimethyl-2-formyl-8-hydroxyquinoline derivatives were synthesized. The use of nitrophenols as the oxidizing agents in the reaction of the appropriate aminophenols with crotonaldehyde leads to a substantial increase in the yields of quinaldines. According to the IR spectroscopic data, the oximes of the formylhydroxyquinolines have a syn configuration.See [1] for communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 235–239, February, 1978.     

Syntheses in the pyridine series

The conditions for obtaining some -dialkylaminoethyl pyrid-4-yl sulfide N¹-oxides and their quaternary salts have been studied. It has been shown that the addition of alkyl iodides to the bases obtained takes place in a similar manner to their addition to pyrid-4-yl sulfides not containing a N-oxide group.For part VII see [1]     

Syntheses in the phenothiazine series

2,3-Dihydrothiazolo[4,5-b]phenothiazine-2-thione was obtained by the reaction of 2-amino-phenothiazine with sulfur and carbon disulfide, and the action of alkyl halides on it was studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 42–44, January, 1971.See [1] for communication XXVIII.     

Syntheses of ortho-Adamantylphenols

Reactions of 1-haloadamantane with aromatic compounds such as benzene, toluene, bromobenzene and so on in the presence of Friedel-Craft type catalysts to afford adamantyl-(1)-benzene derivatives have been reported¹ already, but little is known about the reaction with phenolic cómpounds, the only example being the synthesis of 1,3-bis-(p-hydroxyphenyl)-5,7-dimethyl-adamantane by the reaction of 1,3-dibromo-5,7-dimethyladamantane and phenol reported in a patent literature.²     

Syntheses on the basis of arylfurans

The Meerwein reaction cannot serve as a method for the preparation of 5-arylfurfurals with electron-donor substituents in the benzene ring. A convenient method for the synthesis of such arylfurfurals is formylation of the appropriate arylfurans.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1011–1013, August, 1971.     

Syntheses in the phenothiazine series

Some nucleophilic substitution reactions of 2-methylmercapto-3-methylthiazolo[4,5-b]phenothiazinium methosulfate were studied. Cleavage of the latter with alcoholic alkali gives bis(2-2-methylamino-3-phenothiazinyl) disulfide; cleavage and subsequent alkylation gives new disubstituted phenothiazines.     

Syntheses in the phenothiazine series

3-Aminophenothiazine is synthesized by hydrazinolysis of 3-phthalimidophenothiazine, prepared by thionating 4-phthalimidodiphenylamine. The structure of the compound is confirmed by preparation of derivatives.For Part XVIII see [1]     

Syntheses in the pyridine series

A new procedure for preparing 2-methyl-6-methoxy-4-thioquinolone (I), 2-methyl-7-chloro-4-thioquinoline (II), 2-thiopyridone (III) and 5-nitro-2-thiopyridone (IV) has been proposed. This involves the reactions of the corresponding halogen derivatives of quinoline and pyridine with sodium thiosulfate. Compounds I and II were synthesized for the first time.     

Syntheses in the pyridine series

It has been shown that when they are heated in 2 N caustic soda solution alkyl pyrid-2-yl sulfides are hydrolyzed at the Py-S bond with the formation of pyridones and the corresponding thiols. The latter were determined quantitatively by iodometric titration.For part VIII, see [1].     

螺烯类化合物的合成研究进展

研究发现螺烯类化合物具有优异的光学和电学性质,已经成为有机化学的研究热点之一,综述了近年来螺烯化合物的合成方法研究进展.     

苯并环丁烯类化合物的合成

苯并环丁烯类化合物是一类具有优异特性的聚合物材料,它具有极其广泛的用途和商业开发前景。本文给出了当前苯并环丁烯单体、衍生物和聚合物的合成方法,并简要介绍了苯并环丁烯类化合物在合成研究和工程中的应用。