The [1,5]-Brook rearrangement: an initial application in anion relay chemistry

The [1,5]-Brook rearrangement proceeds efficiently in a series of hydroxyl dithiane substrates with sodium and potassium bases; less effective are lithium bases. That the mode of silyl migration is intramolecular was demonstrated by a crossover experiment. Finally, the tricomponent anion relay chemistry (ARC) coupling tactic was demonstrated employing the [1,5]-Brook rearrangement.     

A modified bischler-napieralski reaction. Synthesis of 2,3,4,9- tetrahydro-1H-pyrido[3,4-B]indole derivatives and their base-catalyzed transformation to N-acetyl-N-[2-[1 -acetyl-2-[1 -(acetyloxy)-1-propenyl]- 1H-indol-3-yl]ethyl]acetamides

The treatment of N-[2-(1H-indol-3-yl)ethyl]alkanamide, 1 (1), with phosphorus oxychloride under controlled conditions gave l-alkyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-ol, 2 . The reaction of 2 with acetic anhydride or with methyl isocyanate at room temperature resulted in the formation of amido carbinol 3 and urea carbinol 7, respectively. The former was transformed into amido ester 4 by boiling acetic anhydride. When the reaction of 3 with acetic anhydride was carried out in the presence of excess triethylamine at 105°, C-N bond cleavage of the tetrahydropyridine ring took place with concurrent bis(N-acetylation) to give the enol ester derivative 5 . The structures of all compounds are consistent with chemical and spectral evidence.     

Cyclisation of 4-[2-Cyclofentenyl]-3-Hydroxy [1] Benzopypan-2-One

4-[2-cyclopentenyl]-3-hydroxy [1] bonzopyran-2-one(3) was cyclised to the bicyclie coumar in-1,3-ethano-2-bromo-1,2-dihydro-3H-pyrano [2,3-c] [1] benzopyran-5-one (6) by a sequence of reactions viz. acetylation of 3, addition of bromine to cyclopenteny double bond and treating the resulting acetyldibromo compound (5) with 4% alcoholic KOH, Cyclisation of compound (3) with mercuric acetate in methanol gave condensed furan derivative 7 which on reductive demercuration with zinc borohydride in dimethoxyethane gave the 1,3-propano-1,2-dihydrofuro [2,3-c] [1] benzopyran-4-one, 8. Cyclisation of compound 2 with come. H₂SO₄ furnished a mixture of bicyclic derivative 9 ad furo coumarin derivative 8.     

功能性二茂铁单、双乙基咪唑的合成

以单、双乙酰基二茂铁为原料,经还原和脱水反应,高效地合成了单、双齿功能性配体--二茂铁乙基咪唑和二茂铁双乙基咪唑,其结构经1H NMR,IR,MS和元素分析表征.     

Synthesis of 4-[3-(1H)-indolyl]-2-[N-guanidinomethyl]thiazole dihydrochloride

The title compound 3b was synthesized in three steps from acetaminothioacetamide ( 4b ) in 15% overall yield. This represents the first synthesis of a 2-guanidinomethylthiazole, which is a homolog of an important pharmacophore, 2-guanidinothiazole.     

A convenient method for the preparation of [1-2H]- and [1-3H]-terminal acetylenes

Conclusions A convenient one-step method has been proposed for the preparation of 1-isotope-substituted acetylenes based on the use of a phase transfer catalyst.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No, 8, pp. 1921–1922, August, 1985.     

One-pot synthesis of 7-bromo-1-[4-(1-cyano-1-methylethyl)]-phenyl-[1,2,4]-triazole-[4,3-a]-quinoxalin

[1,2,4]-Triazole-[4,3-a]-quinoxaline is an important component of many drugs. The yield of the reported methods for triazole cyclization step was usually as low as 20%. In this article, the triazole cyclization step was successfully done by using microwave method with a high yield of 75% for the first time.     

Novel liquid crystals based on [1]benzothieno[3,2- b][1]benzothiophene

Four series of new [1]benzothieno[3,2- b][1]benzothiophene derivatives have been synthesized. In the non-chiral series a SmA phase occurs, while the chiral series exhibits a rather wide antiferroelectric SmC^A* phase just below the SmA phase. The SmA-SmC^A* phase transition has been studied using DSC and dielectric spectroscopy. In the SmC^A* phase the spontaneous quantities have been measured. The tilt angle shows a typical temperature dependence and the values of spontaneous polarization are rather moderate. The length of the helical pitch increases on increasing the length of the non-chiral alkyl chain.     

Novel liquid crystals based on [1]benzothieno[3,2- b ][1]benzothiophene

Four series of new [1]benzothieno[3,2- b ][1]benzothiophene derivatives have been synthesized. In the non-chiral series a SmA phase occurs, while the chiral series exhibits a rather wide antiferroelectric SmC * A phase just below the SmA phase. The SmA-SmC * A phase transition has been studied using DSC and dielectric spectroscopy. In the SmC * A phase the spontaneous quantities have been measured. The tilt angle shows a typical temperature dependence and the values of spontaneous polarization are rather moderate. The length of the helical pitch increases on increasing the length of the non-chiral alkyl chain.     

Properties of 4H-[1]benzopyrano[3,4-c]-[1,2,5]-selenodiazol-4-one

4H-[1]benzopyrano[3,4-c][1,2,5]selenodiazol-4-one has been synthesized by the reaction of 3,4-diaminocoumarin with selenous acid and its reaction with several nucleophiles (alkali, ammonia, amines, hydrazine hydrate) and its nitration have been studied. Using PMR spectroscopy, a comparative kinetic study of the opening of the lactone ring in 6,8-dinitro-4H-[1]benzopyrano[3,4-c][1,2,5]seleno- and thiadiazol-4-ones has been carried out.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 128–133, January, 1991.     

Synthese von Thieno[2,3—d]-1,2,3-triazin- und [1]Benzothieno [2,3—d]-1,2,3-triazin-Derivaten

The title substances, derivatives of two new heterocyclic ring systems, were synthesized by intramolecular cyclisations of diazonium compounds, prepared from derivatives of 2-amino-thiophene-3-carboxamide and of 2-amino-benzo[b]thiophene-3-carboxamide. By-reactions and substitution reactions are mentioned.     

Trimethylbisdehydro[23]- and -[25]annulenones

Syntheses of trimethylbisdehydro [23]- and -[25]annulenones have been described, and the examination of their ¹H NMR spectra suggests the diatropicity and the paratropicity of the 25-membered and 25-membered rings, respectively.     

Biosynthesis of the antibiotic verrucarin E use of [1-13C]-, [2-13C]-, [1,2-13C]- and [2-13C, 2-2H3]-acetates. Verrucarins and roridins, 37th communication [1]

The origin of the carbon skeleton of verrucarin E (1) from acetate as precursor is confirmed. Incorporation studies with [1,2-¹³C]-acetate have demonstrated that two acetoacetate units couple together as shown in pattern A (Scheme 2) and not as in B . Analysis of the deuterium distribution in both verrucarin E (1) isolated after the incorporation of [2-¹³C,2-²H₃]-acetate and in sodium acetate obtained after Kuhn-Roth oxidation of the metabolite demonstrated that C(7) is derived from the starter unit of one of the acetoacetate moieties. The deuterium exchange in verrucarin E (1) occurring during fermentation was investigated.     

5-(1-芳基-1-吡咯-2-基)-1氢-四唑类化合物的合成与表征

利用阳极氧化反应, 将一系列N-芳基吡咯电氰化, 区域专一地得到吡咯氰化物2, 分离收率为76%~85%. 将其与叠氮化钠反应, 合成了一系列具有潜在血管紧张素Ⅱ受体(AT)拮抗活性的新型四唑化合物. 该合成路线的原料易得, 并以阳极氰化芳香氮杂环引入氰基为关键步骤, 可作为在芳香氮杂环上引入四唑基团的通用合成路线.     

The preparation of 8-[4-[4-(2-pyrimidinyl)-1-piperaziny]butyl]-8-azaspiro[4,5] decane-7,9-dione hydrochloride

8-[4-[4-(2-Pyrimidinyl)-1-piperaziny]butyl]-8-azaspiro [4,5] decane-7,9-dione hydrochloride (buspirone hydrochloride) was obtained in one pot with a 51.8% overall yield. The key intermediate, 1-(2-pyrimidinyl) piperazine, was synthesized through chlorination and cyclization condensation reaction with diethanolamine as initial material. This modified protocol has the notable advantages of mild reaction condition, convenient operation, and high overall yield.