An alternative construction of A-B-D ring-system of erythrinan and homoerythrinan alkaloids by TiCl4-mediated tandem semipinacol/intramolecular Schmidt reaction of α-siloxyepoxyazide was addressed and the unusual epo...An alternative construction of A-B-D ring-system of erythrinan and homoerythrinan alkaloids by TiCl4-mediated tandem semipinacol/intramolecular Schmidt reaction of α-siloxyepoxyazide was addressed and the unusual epoxidation stereoselectivity was observed in preparation of the substrate once again.展开更多
In the presence of K2CO3, 2-hydroxyethyltripheny phosphonium bromide (1) reacts with substituted salicylaldehyde (2) and 2-hydroxy-1 naphthaldehyde (4) at 110 ℃ in a sealed tube. The title compounds were prepared in ...In the presence of K2CO3, 2-hydroxyethyltripheny phosphonium bromide (1) reacts with substituted salicylaldehyde (2) and 2-hydroxy-1 naphthaldehyde (4) at 110 ℃ in a sealed tube. The title compounds were prepared in medium yield. The ratio of bromide (1) to aldehyde derivatives was also discussed in this paper.展开更多
Asymmetric 6-substituted-2-methoxy-4-(2,4-dichlorophenyl)-4H-1,3,2-benzodioxaphosphorin a-sulfides were prepared from intramolecular cyclization. The diastereomers were separated by column chromatography and fractiona...Asymmetric 6-substituted-2-methoxy-4-(2,4-dichlorophenyl)-4H-1,3,2-benzodioxaphosphorin a-sulfides were prepared from intramolecular cyclization. The diastereomers were separated by column chromatography and fractional crystallization. Their structures were characterized on the basis of H-1 NMR, P-31 NMR and x-ray diffraction analysis.展开更多
The present study reports the reaction of 4-bromomethylcoumarins with salicylidineaniline in acetone with two equivalents of potassium carbonate resulted in the formation of title compounds at room temperature via int...The present study reports the reaction of 4-bromomethylcoumarins with salicylidineaniline in acetone with two equivalents of potassium carbonate resulted in the formation of title compounds at room temperature via intramolecular aldolization. The obtained compound is thermodynamically and kinetically stable with highly stereoselective and excellent yield.展开更多
Low-valent titanium reagent prepared in situ from TiCl_4 and Zn was employed to induce the intramolecular coupling of nitro group with carbonyl group to give substituted hydroxyl pyrrolines, pyrroles and lactam in goo...Low-valent titanium reagent prepared in situ from TiCl_4 and Zn was employed to induce the intramolecular coupling of nitro group with carbonyl group to give substituted hydroxyl pyrrolines, pyrroles and lactam in good yields.展开更多
The intramolecular reductive coupling reaction of 1,6-bis(subshtuted indolyl)hexane-1,6-dione using zero-valent titanium reagent as catalyst proderes the novel photochromic 1,2-diheterocyclic cyclohexenes 2, together ...The intramolecular reductive coupling reaction of 1,6-bis(subshtuted indolyl)hexane-1,6-dione using zero-valent titanium reagent as catalyst proderes the novel photochromic 1,2-diheterocyclic cyclohexenes 2, together with unexpected compounds 3展开更多
A new condensation reaction of β-keto-δ-valerolactones was developed. The condensation products are composed of a pair of isomers because of the formation ofintramolecular hydrogen bond. Their structures were confir...A new condensation reaction of β-keto-δ-valerolactones was developed. The condensation products are composed of a pair of isomers because of the formation ofintramolecular hydrogen bond. Their structures were confirmed by 1HNMR and elemental analysis.展开更多
A theoretical approach to polycondensation reaction of Aa-Bb type Involving intramolecular cycllzatlon has been proposed by Tang Au-chin et al.. In this paper, the theoretical sol-gel distribution is tested by polycon...A theoretical approach to polycondensation reaction of Aa-Bb type Involving intramolecular cycllzatlon has been proposed by Tang Au-chin et al.. In this paper, the theoretical sol-gel distribution is tested by polycondensation of adipic acid with trimethylol propane in a sto-ichiometric ratio of 0. 8, and the effect of intramolecular cyclization is discussed in detail.展开更多
We reported that a benzyl-type binaphthyl disulfone could be conveniently converted into dibenzophenanthrene. Thus, racemic 1 was treated with lithium diisopropylamide (LDA) afforded dl-dibenzophenanthrene in a modera...We reported that a benzyl-type binaphthyl disulfone could be conveniently converted into dibenzophenanthrene. Thus, racemic 1 was treated with lithium diisopropylamide (LDA) afforded dl-dibenzophenanthrene in a moderate yield, together with an unknown benzensulfonyl-substituted derivative 2. The structures were confirmed by MS, 1H, 13C NMR and elemental analysis. The reaction might involve the initial intramolecular nucleophilic substitution to produce an intermediate 3, followed by elimination of benzenesulfinic acid to form dibenzophenanthrene.展开更多
文摘An alternative construction of A-B-D ring-system of erythrinan and homoerythrinan alkaloids by TiCl4-mediated tandem semipinacol/intramolecular Schmidt reaction of α-siloxyepoxyazide was addressed and the unusual epoxidation stereoselectivity was observed in preparation of the substrate once again.
文摘In the presence of K2CO3, 2-hydroxyethyltripheny phosphonium bromide (1) reacts with substituted salicylaldehyde (2) and 2-hydroxy-1 naphthaldehyde (4) at 110 ℃ in a sealed tube. The title compounds were prepared in medium yield. The ratio of bromide (1) to aldehyde derivatives was also discussed in this paper.
文摘Asymmetric 6-substituted-2-methoxy-4-(2,4-dichlorophenyl)-4H-1,3,2-benzodioxaphosphorin a-sulfides were prepared from intramolecular cyclization. The diastereomers were separated by column chromatography and fractional crystallization. Their structures were characterized on the basis of H-1 NMR, P-31 NMR and x-ray diffraction analysis.
文摘The present study reports the reaction of 4-bromomethylcoumarins with salicylidineaniline in acetone with two equivalents of potassium carbonate resulted in the formation of title compounds at room temperature via intramolecular aldolization. The obtained compound is thermodynamically and kinetically stable with highly stereoselective and excellent yield.
文摘Low-valent titanium reagent prepared in situ from TiCl_4 and Zn was employed to induce the intramolecular coupling of nitro group with carbonyl group to give substituted hydroxyl pyrrolines, pyrroles and lactam in good yields.
文摘The intramolecular reductive coupling reaction of 1,6-bis(subshtuted indolyl)hexane-1,6-dione using zero-valent titanium reagent as catalyst proderes the novel photochromic 1,2-diheterocyclic cyclohexenes 2, together with unexpected compounds 3
文摘A new condensation reaction of β-keto-δ-valerolactones was developed. The condensation products are composed of a pair of isomers because of the formation ofintramolecular hydrogen bond. Their structures were confirmed by 1HNMR and elemental analysis.
文摘A theoretical approach to polycondensation reaction of Aa-Bb type Involving intramolecular cycllzatlon has been proposed by Tang Au-chin et al.. In this paper, the theoretical sol-gel distribution is tested by polycondensation of adipic acid with trimethylol propane in a sto-ichiometric ratio of 0. 8, and the effect of intramolecular cyclization is discussed in detail.
文摘We reported that a benzyl-type binaphthyl disulfone could be conveniently converted into dibenzophenanthrene. Thus, racemic 1 was treated with lithium diisopropylamide (LDA) afforded dl-dibenzophenanthrene in a moderate yield, together with an unknown benzensulfonyl-substituted derivative 2. The structures were confirmed by MS, 1H, 13C NMR and elemental analysis. The reaction might involve the initial intramolecular nucleophilic substitution to produce an intermediate 3, followed by elimination of benzenesulfinic acid to form dibenzophenanthrene.
