Intramolecular cyclization of A catalyzed by IDA in benzene or THF yields two γ-lactams through C-alkylation and one δ-and one 7-membered lactam by O-alkylation.
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
25,27-Dipropoxy-p-tert-butylcalix[4]crown-9 cone conformer 5 was readily synthesized via an intramolecular cyclization strategy in good yields. The structures of all the new compounds involved were confirmed by NMR, E...25,27-Dipropoxy-p-tert-butylcalix[4]crown-9 cone conformer 5 was readily synthesized via an intramolecular cyclization strategy in good yields. The structures of all the new compounds involved were confirmed by NMR, ESI-MS and elemental analyses. All of them were proved to be in the cone conformation.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
A convenient and efficient method for the highly regioselecfive synthesis of indene derivatives 4 and 5 from tetraaryl substituted 1,3-butadienes 3 was described. The method involves an intramolecular Friedel-Crafts c...A convenient and efficient method for the highly regioselecfive synthesis of indene derivatives 4 and 5 from tetraaryl substituted 1,3-butadienes 3 was described. The method involves an intramolecular Friedel-Crafts cyclization and a corresponding double-bond positional shift of isomers 4 and 5 in the presence of different Lewis acids under mild conditions with higher than 90% yields.展开更多
Three synthetic routes for the preparation of nitrogen containing cyclic compounds have been developed, in which the assembling of Fomc-Lys(Boc) residue at N-terminal of resin-bound intermediates is a key prerequisite...Three synthetic routes for the preparation of nitrogen containing cyclic compounds have been developed, in which the assembling of Fomc-Lys(Boc) residue at N-terminal of resin-bound intermediates is a key prerequisite. Six peptides with nitrogen containing local cyclic structure were efficiently synthesized in good yield starting from chloromethyl resin.展开更多
Treatment of N-alkoxyamides with bis（trifluoroacetoxy）iodobenzene generated electron deficient nitrogen species, which readily cyclized onto aromatic ring to give N-alkoxy-2- oxoindoles. The effect of different subs...Treatment of N-alkoxyamides with bis（trifluoroacetoxy）iodobenzene generated electron deficient nitrogen species, which readily cyclized onto aromatic ring to give N-alkoxy-2- oxoindoles. The effect of different substituent on aromatic ring to the electrophilic substitution was studied.展开更多
As a versatile type of enzyme,carboxylic acid reductases(CAR)can not only reduce various carboxylic acids to aldehydes in cooperation with cofactors ATP and NADPH but also catalyze the synthesis of amides and esters i...As a versatile type of enzyme,carboxylic acid reductases(CAR)can not only reduce various carboxylic acids to aldehydes in cooperation with cofactors ATP and NADPH but also catalyze the synthesis of amides and esters in the absence of NADPH.Here,we report an intramolecular cyclization catalyzed by CAR only with the use of ATP to transform amino acids into diverse lactams,includingγ-/δ-/ε-lactams and chiral derivatives thereof.The observed wide substrate scope and selectivity enable potential applications to be implemented.Our results demonstrate that CAR-catalyzed lactamization is a promising approach for the synthesis of chiral lactam com-pounds under mild conditions,thereby enriching the toolbox for the biosynthesis of lactams as a viable alternative to purely chemical procedures.展开更多
Aurone derivatives were synthesized in good to high yields by PBu_(3)-catalyzed intramolecular 5-exo cyclization of 2-alkynoylphenols.The reaction proceeds in high regioselectivity without forming 6-endo cyclization p...Aurone derivatives were synthesized in good to high yields by PBu_(3)-catalyzed intramolecular 5-exo cyclization of 2-alkynoylphenols.The reaction proceeds in high regioselectivity without forming 6-endo cyclization products.展开更多
The title compounds 5a-5c were prepared via the reaction of methyl 2-perfluoroalkynoates (4) with methyl 5-oxo-4-(triphenylphosphoranylidene)hex-2-enoate (3), which was obtained from the reaction of methyl propynate (...The title compounds 5a-5c were prepared via the reaction of methyl 2-perfluoroalkynoates (4) with methyl 5-oxo-4-(triphenylphosphoranylidene)hex-2-enoate (3), which was obtained from the reaction of methyl propynate (2) with acetylmethylenetriphenylphosphorane (1) at -5-0 degrees C. Intramolecular elimination of Ph(3)PO took place when compound 5 was heated in aqueous methanol at 115-120 degrees C in sealed tube, yielding dimethyl 2-trifluoromethyl-4-methylisophthalate (6a) from 5a and methyl 5-acetyl-4-hydroxy-2-heptafluoropropanylbenzoate (6b) from 5b, respectively. The structures of compounds 5, 6a and 6b were confirmed by IR, MS, H-1 NMR, F-19 NMR and C-13 NMR spectroscopy and elemental analyses. Rection mechanisms for the formation of compounds 5, 6a and 6b were proposed.展开更多
The conventional free radical polymerization(FRP) of multivinyl monomers(MVMs) inevitably leads to gelation even at low monomer conversion resulting in difficulties to control and monitor the reaction process. Flory a...The conventional free radical polymerization(FRP) of multivinyl monomers(MVMs) inevitably leads to gelation even at low monomer conversion resulting in difficulties to control and monitor the reaction process. Flory and Stockmayer(F-S theory)studied it based on two fundamental assumptions:(1) independent and equivalent vinyl groups;(2) no intramolecular cyclization.However, until now its applicability to FRP of MVMs(especially regarding the extent of intramolecular cyclization) is still controversial. In this paper, Monte Carlo simulations are used to study FRP of divinyl monomers by two kinetic models:with/without cyclization models. The results of the simulations are compared with the calculated gel points based on F-S theory and the experimental data. It is found that the intramolecular cyclization has a negligible impact on the polymerization process and the gel point before gelation, which are in agreement with the prediction by F-S theory, but the effect becomes significant above the gel points.展开更多
Utilization of intermolecular Friedel-Crafts and intramolecular condensation reaction,novel 1,3-di-(pyridine-2-yl)benzene(N,C,N terdentate)skeleton with electro-withdrawing group in 6'position of pyridyl and a cyc...Utilization of intermolecular Friedel-Crafts and intramolecular condensation reaction,novel 1,3-di-(pyridine-2-yl)benzene(N,C,N terdentate)skeleton with electro-withdrawing group in 6'position of pyridyl and a cyclization between 6'position of pyridyl and 6 position of benzyl ring were firstly designed and synthesized.The structures of these novel N,C,N terdentate were confirmed by NMR,MS and X-ray single crystalanalyses.The photophysical properties of these compounds were briefly explored.展开更多
A convenient one-step synthesis of five-membered or six-membered imino-protected cyclic guanidine via an intramolecular ring-closure reaction of alkyl diamine（2a-2g） with 1,3-diamino-protected methylisothiourea（1a ...A convenient one-step synthesis of five-membered or six-membered imino-protected cyclic guanidine via an intramolecular ring-closure reaction of alkyl diamine（2a-2g） with 1,3-diamino-protected methylisothiourea（1a and 1b） was established and investigated.Amino guanidine such as 3-（2-aminoethyl）-1,2-dibenzyloxycarbonylguanidine（4a） has been proved to be the intermediate of the reaction via utilizing mono-protected diamine as starting material.The intramolecular ring closure of 4a results in 2-benzyloxycarbonyliminoimidazolidine（3a）.This new one-step synthesis has advantages of simple condition,easy workup procedure and reasonable yield.展开更多
The organoselenium-induced ring-closure reaction of O-allyl oximes gave cyclic iminium salts, which reacted with Grignard reagents to produce N-alkyl-4-phenylselenoisoxazolidines. 2,5-Dihydroisoxazoles could be obtain...The organoselenium-induced ring-closure reaction of O-allyl oximes gave cyclic iminium salts, which reacted with Grignard reagents to produce N-alkyl-4-phenylselenoisoxazolidines. 2,5-Dihydroisoxazoles could be obtained in good yields by subsequent selenoxide syn-elimination.展开更多
The synthesis of the title compounds starting with the chemoselective dehydrogenation of 3-[2-(3,4-dihydro-1-naphthalenyl)ethyl]imidazolidine-2,4-diones has been described.
The total syntheses of 8-oxyberberine and oxohomoberberines were accomplished starting from commercially available 5-bromobenzo[d][1,3]dioxole,piperonal and sesamol in high total yield.The key steps involved a modifie...The total syntheses of 8-oxyberberine and oxohomoberberines were accomplished starting from commercially available 5-bromobenzo[d][1,3]dioxole,piperonal and sesamol in high total yield.The key steps involved a modified Pomeranz-Fritsch reaction and the intramolecular Heck cyclization.This approach is short,convenient and suitable for the preparation of homoberberine analogues.展开更多
文摘Intramolecular cyclization of A catalyzed by IDA in benzene or THF yields two γ-lactams through C-alkylation and one δ-and one 7-membered lactam by O-alkylation.
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.
基金the Research Foundation of Tongji Medical College,Huazhong University of Science and Technology(No.25514107)Project Chenguang of Wuhan City(No.200750731267)for financial support.
文摘25,27-Dipropoxy-p-tert-butylcalix[4]crown-9 cone conformer 5 was readily synthesized via an intramolecular cyclization strategy in good yields. The structures of all the new compounds involved were confirmed by NMR, ESI-MS and elemental analyses. All of them were proved to be in the cone conformation.
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.
基金Project supported by the National Natural Science Foundation of China （No, 203900506） and the Shanghai Municipal Committee of Science and Technology （Nos, 05JC14057, 054319901）,
文摘A convenient and efficient method for the highly regioselecfive synthesis of indene derivatives 4 and 5 from tetraaryl substituted 1,3-butadienes 3 was described. The method involves an intramolecular Friedel-Crafts cyclization and a corresponding double-bond positional shift of isomers 4 and 5 in the presence of different Lewis acids under mild conditions with higher than 90% yields.
文摘Three synthetic routes for the preparation of nitrogen containing cyclic compounds have been developed, in which the assembling of Fomc-Lys(Boc) residue at N-terminal of resin-bound intermediates is a key prerequisite. Six peptides with nitrogen containing local cyclic structure were efficiently synthesized in good yield starting from chloromethyl resin.
文摘Treatment of N-alkoxyamides with bis（trifluoroacetoxy）iodobenzene generated electron deficient nitrogen species, which readily cyclized onto aromatic ring to give N-alkoxy-2- oxoindoles. The effect of different substituent on aromatic ring to the electrophilic substitution was studied.
基金supported by the National Key Research and Development Program of China(No.2019YFA0905100)the National Natural Science Foundation of China(No.31900909)+1 种基金the Natural Science Foundation Applying a system of Tianjin(No.21JCJQJC00110)and Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project(No.TSBICIP-CXRC-009)Mr Qu also thanks financial support from Youth Innovation Promotion Association,CAS(No.2021175).
文摘As a versatile type of enzyme,carboxylic acid reductases(CAR)can not only reduce various carboxylic acids to aldehydes in cooperation with cofactors ATP and NADPH but also catalyze the synthesis of amides and esters in the absence of NADPH.Here,we report an intramolecular cyclization catalyzed by CAR only with the use of ATP to transform amino acids into diverse lactams,includingγ-/δ-/ε-lactams and chiral derivatives thereof.The observed wide substrate scope and selectivity enable potential applications to be implemented.Our results demonstrate that CAR-catalyzed lactamization is a promising approach for the synthesis of chiral lactam com-pounds under mild conditions,thereby enriching the toolbox for the biosynthesis of lactams as a viable alternative to purely chemical procedures.
基金The authors are grateful to the financial support from the National Natural Science Foundation of China(No.21272004).
文摘Aurone derivatives were synthesized in good to high yields by PBu_(3)-catalyzed intramolecular 5-exo cyclization of 2-alkynoylphenols.The reaction proceeds in high regioselectivity without forming 6-endo cyclization products.
基金Project supported by the National Natural Science Foundation of China.
文摘The title compounds 5a-5c were prepared via the reaction of methyl 2-perfluoroalkynoates (4) with methyl 5-oxo-4-(triphenylphosphoranylidene)hex-2-enoate (3), which was obtained from the reaction of methyl propynate (2) with acetylmethylenetriphenylphosphorane (1) at -5-0 degrees C. Intramolecular elimination of Ph(3)PO took place when compound 5 was heated in aqueous methanol at 115-120 degrees C in sealed tube, yielding dimethyl 2-trifluoromethyl-4-methylisophthalate (6a) from 5a and methyl 5-acetyl-4-hydroxy-2-heptafluoropropanylbenzoate (6b) from 5b, respectively. The structures of compounds 5, 6a and 6b were confirmed by IR, MS, H-1 NMR, F-19 NMR and C-13 NMR spectroscopy and elemental analyses. Rection mechanisms for the formation of compounds 5, 6a and 6b were proposed.
基金supported by the National Natural Science Foundation of China(51573129)Science Foundation Ireland Principal Investigator Award(13/IA/1962)+1 种基金Investigator Award(12/IP/1688)Health Research Board(HRA-POR-2013-412)
文摘The conventional free radical polymerization(FRP) of multivinyl monomers(MVMs) inevitably leads to gelation even at low monomer conversion resulting in difficulties to control and monitor the reaction process. Flory and Stockmayer(F-S theory)studied it based on two fundamental assumptions:(1) independent and equivalent vinyl groups;(2) no intramolecular cyclization.However, until now its applicability to FRP of MVMs(especially regarding the extent of intramolecular cyclization) is still controversial. In this paper, Monte Carlo simulations are used to study FRP of divinyl monomers by two kinetic models:with/without cyclization models. The results of the simulations are compared with the calculated gel points based on F-S theory and the experimental data. It is found that the intramolecular cyclization has a negligible impact on the polymerization process and the gel point before gelation, which are in agreement with the prediction by F-S theory, but the effect becomes significant above the gel points.
基金Financial support was from the National Natural Science Foundation of China(Nos.51773021,51911530197,U1663229,51473140)Six talent peaks project in Jiangsu Province(No.XCL-102)+2 种基金the Talent project of Jiangsu Specially-Appointed ProfessorNatural Science Fund for Colleges and Universities in Jiangsu Province(No.19KJA430002)the Open Fund of Key Laboratory of Advanced Display and System Applications of Ministry of Education,Shanghai University and Natural Science Foundation of Hunan Province(No.2017JJ2245)
文摘Utilization of intermolecular Friedel-Crafts and intramolecular condensation reaction,novel 1,3-di-(pyridine-2-yl)benzene(N,C,N terdentate)skeleton with electro-withdrawing group in 6'position of pyridyl and a cyclization between 6'position of pyridyl and 6 position of benzyl ring were firstly designed and synthesized.The structures of these novel N,C,N terdentate were confirmed by NMR,MS and X-ray single crystalanalyses.The photophysical properties of these compounds were briefly explored.
基金Project 81001366 supported by NSFC and basic scientific research foundation of Institute of Materia Medica(No.2009CHX07) for financial support.
文摘A convenient one-step synthesis of five-membered or six-membered imino-protected cyclic guanidine via an intramolecular ring-closure reaction of alkyl diamine（2a-2g） with 1,3-diamino-protected methylisothiourea（1a and 1b） was established and investigated.Amino guanidine such as 3-（2-aminoethyl）-1,2-dibenzyloxycarbonylguanidine（4a） has been proved to be the intermediate of the reaction via utilizing mono-protected diamine as starting material.The intramolecular ring closure of 4a results in 2-benzyloxycarbonyliminoimidazolidine（3a）.This new one-step synthesis has advantages of simple condition,easy workup procedure and reasonable yield.
基金Project supported by the National Natural Science Foundation of China (Nos. 20332060,20272050).
文摘The organoselenium-induced ring-closure reaction of O-allyl oximes gave cyclic iminium salts, which reacted with Grignard reagents to produce N-alkyl-4-phenylselenoisoxazolidines. 2,5-Dihydroisoxazoles could be obtained in good yields by subsequent selenoxide syn-elimination.
文摘The synthesis of the title compounds starting with the chemoselective dehydrogenation of 3-[2-(3,4-dihydro-1-naphthalenyl)ethyl]imidazolidine-2,4-diones has been described.
基金This work was supported by the National Natural Science Foundation of China(No.81373259).
文摘The total syntheses of 8-oxyberberine and oxohomoberberines were accomplished starting from commercially available 5-bromobenzo[d][1,3]dioxole,piperonal and sesamol in high total yield.The key steps involved a modified Pomeranz-Fritsch reaction and the intramolecular Heck cyclization.This approach is short,convenient and suitable for the preparation of homoberberine analogues.
