The mechanism of nitrocompounds quenching of the fluorescence of 5, 5′ dipheny1 2, 2′ bisoxazole (POOP) and trans 1, 2 bis [2 (5 phenyloxazolyl)] ethene (POEOP) has been studied. It was found that the fluores...The mechanism of nitrocompounds quenching of the fluorescence of 5, 5′ dipheny1 2, 2′ bisoxazole (POOP) and trans 1, 2 bis [2 (5 phenyloxazolyl)] ethene (POEOP) has been studied. It was found that the fluorescence of oxazoles was quenched mainly by the absorption competition and radiationless energy transfer of nitrocompounds. The fluorescence quenching rate constants of nitrobenzene and nitromethane are 3.0×10 10 L·mol -1 ·s -1 and 1.5×10 8 L·mol -1 ·s -1 respectively for POEOP. This remarkable difference was explicated.展开更多
Disubstituted oxazoles were prepared conveniently by treatment of aromatic -methyl ketones and nitriles with poly[styrene(iodosodiacetate)] in one-pot process.
In this work,NH_(2)-substituted oxazoles and NO_(2)/NF_(2)/NHNO_(2)-substituted ethylenes/acetylenes were designed and used as dienes and dienophiles,respectively,in order to develop new bridge-ring insensitive high e...In this work,NH_(2)-substituted oxazoles and NO_(2)/NF_(2)/NHNO_(2)-substituted ethylenes/acetylenes were designed and used as dienes and dienophiles,respectively,in order to develop new bridge-ring insensitive high energy compounds through the Diels-Alder reaction between them.The reaction type,reaction feasibility and performance of reaction products were investigated in detail theoretically.The results showed that dienes most possibly react with dienophiles through the HOMO-diene controlled normal Diels-Alder reaction at relatively low energy barrier.Tetranitroethylene could react with the designed dienes much more easily than other dienophiles,and was employed to further design 29 new bridge-ring energetic compounds.Due to high heat of formation,density and oxygen balance,all designed bridge-ring energetic compounds have outstanding detonation performance,16 of them have higher energy than HMX(1,3,5,7-tetranitro-1,3,5,7-tetrazocine)and 2 others even possess comparative energy with the representative of high energy compounds CL-20(2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane).The predicted average h50 value of these bridge-ring energetic compounds is 83 cm,showing their low impact sensitivity.The NH2 groups could obviously impel the proceeding of Diels-Alder reactions,but would slightly decrease the energy and sensitivity performance.In all,the new designed bridge-ring compounds have both high energy and low sensitivity,and may be produced through Diels-Alder reactions at relatively low energy barrier.This paper may be helpful for the theoretical design and experiment synthesis of new advanced insensitive high energy compounds.展开更多
An efficient N–H and C(sp~3)-H functionalization of aryl ketones with benzylamines/amino acids was developed under mild conditions by virtue of anodic oxidation. A variety of functionalized 2,5-diaryloxazoles were ob...An efficient N–H and C(sp~3)-H functionalization of aryl ketones with benzylamines/amino acids was developed under mild conditions by virtue of anodic oxidation. A variety of functionalized 2,5-diaryloxazoles were obtained with good to excellent yields. Moreover, some important natural products can be prepared by this method. The reaction features a broad substrate scope, scalability, metal-free and chemical oxidant-free.展开更多
Main observation and conclusion A facile and efficient strategy for the synthesis of 5-aryl-2-(quinolin-2-yl)oxazoles via rhodium-catalyzed formal[3+2]cyclization of 4-aryl-1-tosyl-1H-1,2,3-triazoles with quinoline-2-...Main observation and conclusion A facile and efficient strategy for the synthesis of 5-aryl-2-(quinolin-2-yl)oxazoles via rhodium-catalyzed formal[3+2]cyclization of 4-aryl-1-tosyl-1H-1,2,3-triazoles with quinoline-2-carbaldehydes has been described.The protocol employs mild conditions and offers good yields of diverse 2,5-aryloxazole derivatives with a broad reaction scope.It is amenable to gram-scale synthesis and easily transformation.Moreover,this 5-aryl-2-(quinolin-2-yl)oxazole skeleton is indeed a new fluorophore and its applications in metal ions probes are also investigated and showed fluorescent responses to mercury ion.展开更多
Disubstituted oxazoles were prepared conveniently by treatment of aromatic -methyl ketones and nitriles with poly[styrene(iodosodiacetate)] in a one-pot manner.
A practical one-pot protocol for the synthesis of 2,5-disubstituted oxazoles from 1-aryl-2-nitroethanones was reported. In the presence of iron/AcOH in acetonitrile, the reaction of 1-aryl-2-nitroethanones with trimet...A practical one-pot protocol for the synthesis of 2,5-disubstituted oxazoles from 1-aryl-2-nitroethanones was reported. In the presence of iron/AcOH in acetonitrile, the reaction of 1-aryl-2-nitroethanones with trimethyl orthoacetate or trimethyl orthobenzoate delivered the corresponding 2,5-disubstituted oxazoles in moderate to good yields.展开更多
Nine 5-aryl-2-methyloxazole derivatives were synthesized via gold-catalyzed alkyne oxidation. All of the compounds have been screened for their antiproliferative activities against MCF-7 cell （human breast carcinoma...Nine 5-aryl-2-methyloxazole derivatives were synthesized via gold-catalyzed alkyne oxidation. All of the compounds have been screened for their antiproliferative activities against MCF-7 cell （human breast carcinoma）, A549 cell （human lung carcinoma） and Hela cell （human cervical carcinoma） lines in vitro. The results revealed that compounds 1b, 1c and 1d exhibited strong inhibitory activities against the MCF-7 cell lines （with ICso values of 4.6, 9.7 and 2.2 μmol/L, respectively）.展开更多
In the presence of Cu（OAc）2·H2O, a variety of 5-trifluoromethyl-2,4-disubstituted oxazoles were easily synthesized via t-BuOOH （TBHP）/I2-mediated tandem oxidative cyclization from readily available starting m...In the presence of Cu（OAc）2·H2O, a variety of 5-trifluoromethyl-2,4-disubstituted oxazoles were easily synthesized via t-BuOOH （TBHP）/I2-mediated tandem oxidative cyclization from readily available starting materials aryl methanamines and α-trifluoroacetyl-substituted ketones or esters under mild conditions, The mechanism was proposed.展开更多
以L-丝氨酸、L-丙氨酸和L-苏氨酸为起始原料,采用两种不同的方法分别合成了天然海洋化合物Leucam ide A的关键中间体口恶唑化合物Ⅰ及甲基口恶唑化合物Ⅱ。甲酯保护的L-丝氨酸和叔丁氧羰基保护的L-丙氨酸为原料,以N,N′-二环己基碳二亚...以L-丝氨酸、L-丙氨酸和L-苏氨酸为起始原料,采用两种不同的方法分别合成了天然海洋化合物Leucam ide A的关键中间体口恶唑化合物Ⅰ及甲基口恶唑化合物Ⅱ。甲酯保护的L-丝氨酸和叔丁氧羰基保护的L-丙氨酸为原料,以N,N′-二环己基碳二亚胺(DCC)为缩合试剂,1-羟基苯并三氮唑(HOB t)为助剂,三乙胺为碱,缩合得到二肽后,利用Burgess试剂关环成口恶唑啉,再以1,8-二氮杂二环[5.4.0]十一烷-7-烯(DBU)和B rCC l3进行氧化脱氢,得到口恶唑化合物Ⅰ,收率为47.8%。甲基口恶唑化合物Ⅱ是以L-丝胺酸和L-苏氨酸为起始化合物。L-丝胺酸经甲酯化,叔丁氧羰基保护氨基后,以2,2-二甲氧基丙烷进行羟基和氨基的双保护,脱甲酯得到Garner酸,再与甲酯保护的L-苏氨酸缩合得到二肽。利用Dess-M artin Period inane试剂氧化其中的仲羟基,以三苯基膦和碘为试剂关环得到甲基口恶唑Ⅱ,反应收率46.1%。目标化合物及中间体结构经NMR进行了鉴定。展开更多
The purification of 4,5-diphenyl-2-methyloxazole preparation was improved.Influences of concentration and solvent on the fluorescent property of 4,5-diphenyl-2-methyloxazole and 4,5-diphenyl-2-styryloxazole were studi...The purification of 4,5-diphenyl-2-methyloxazole preparation was improved.Influences of concentration and solvent on the fluorescent property of 4,5-diphenyl-2-methyloxazole and 4,5-diphenyl-2-styryloxazole were studied,and fluorescence quantum yield(Φ)of the two compound were also studied in the paper.展开更多
文摘The mechanism of nitrocompounds quenching of the fluorescence of 5, 5′ dipheny1 2, 2′ bisoxazole (POOP) and trans 1, 2 bis [2 (5 phenyloxazolyl)] ethene (POEOP) has been studied. It was found that the fluorescence of oxazoles was quenched mainly by the absorption competition and radiationless energy transfer of nitrocompounds. The fluorescence quenching rate constants of nitrobenzene and nitromethane are 3.0×10 10 L·mol -1 ·s -1 and 1.5×10 8 L·mol -1 ·s -1 respectively for POEOP. This remarkable difference was explicated.
文摘Disubstituted oxazoles were prepared conveniently by treatment of aromatic -methyl ketones and nitriles with poly[styrene(iodosodiacetate)] in one-pot process.
基金the Natural Science Foundation of Jiangsu(BK20170761)Natural Science Foundation of Nanjing Institute of Technology(JCYJ201806)+1 种基金Science Innovation Project for Undergraduates of Nanjing Institute of Technology(TB202002005)Outstanding Scientific and Technological Innovation Team in Colleges and Universities of Jiangsu Province,and Jiangsu Overseas Visiting Scholar Program for University Prominent Young&Middle-aged Teachers and Presidents.
文摘In this work,NH_(2)-substituted oxazoles and NO_(2)/NF_(2)/NHNO_(2)-substituted ethylenes/acetylenes were designed and used as dienes and dienophiles,respectively,in order to develop new bridge-ring insensitive high energy compounds through the Diels-Alder reaction between them.The reaction type,reaction feasibility and performance of reaction products were investigated in detail theoretically.The results showed that dienes most possibly react with dienophiles through the HOMO-diene controlled normal Diels-Alder reaction at relatively low energy barrier.Tetranitroethylene could react with the designed dienes much more easily than other dienophiles,and was employed to further design 29 new bridge-ring energetic compounds.Due to high heat of formation,density and oxygen balance,all designed bridge-ring energetic compounds have outstanding detonation performance,16 of them have higher energy than HMX(1,3,5,7-tetranitro-1,3,5,7-tetrazocine)and 2 others even possess comparative energy with the representative of high energy compounds CL-20(2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane).The predicted average h50 value of these bridge-ring energetic compounds is 83 cm,showing their low impact sensitivity.The NH2 groups could obviously impel the proceeding of Diels-Alder reactions,but would slightly decrease the energy and sensitivity performance.In all,the new designed bridge-ring compounds have both high energy and low sensitivity,and may be produced through Diels-Alder reactions at relatively low energy barrier.This paper may be helpful for the theoretical design and experiment synthesis of new advanced insensitive high energy compounds.
基金the financial support from the National Natural Science Foundation of China (Nos.2177218522001241)+1 种基金the support from the Science and Technology Major Project of Anhui Province of China (No.201903a07020003)the Science and Technology Major Project of Fuyang of Anhui Province of China(No.FK20208018)。
文摘An efficient N–H and C(sp~3)-H functionalization of aryl ketones with benzylamines/amino acids was developed under mild conditions by virtue of anodic oxidation. A variety of functionalized 2,5-diaryloxazoles were obtained with good to excellent yields. Moreover, some important natural products can be prepared by this method. The reaction features a broad substrate scope, scalability, metal-free and chemical oxidant-free.
基金the National Natural Sci-ence Foundation of China(No.21772001)the Anhui Provincial Natural Science Foundation(No.1808085MB41)the Cultiva-tion Project for University Outstanding Talents of Anhui Province(2019).
文摘Main observation and conclusion A facile and efficient strategy for the synthesis of 5-aryl-2-(quinolin-2-yl)oxazoles via rhodium-catalyzed formal[3+2]cyclization of 4-aryl-1-tosyl-1H-1,2,3-triazoles with quinoline-2-carbaldehydes has been described.The protocol employs mild conditions and offers good yields of diverse 2,5-aryloxazole derivatives with a broad reaction scope.It is amenable to gram-scale synthesis and easily transformation.Moreover,this 5-aryl-2-(quinolin-2-yl)oxazole skeleton is indeed a new fluorophore and its applications in metal ions probes are also investigated and showed fluorescent responses to mercury ion.
基金Project supported by the National Natural Science Foundation of China (No. 29932020).
文摘Disubstituted oxazoles were prepared conveniently by treatment of aromatic -methyl ketones and nitriles with poly[styrene(iodosodiacetate)] in a one-pot manner.
基金Supporting information for this article is available on the WWW under http：//dx.cloi.org/10, 1002/cjoc.201100683 or from the author. AcknowledgementWe thank the National Natural Science Foundationof China （Nos. 20872087, 21002061, 20902057, 21142012）, the State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Leading Academic Discipline Project of Shanghai Municipal Education Commission （No. J50101）, and the Graduate Innovation Fund of Shanghai University for financial support. We thank Dr. Hongmei Deng （Laboratory for Microstructures, Shanghai University） for NMR measurements. We are indebted to Professor Ran Hong of SIOC for enlightening discussions.
文摘A practical one-pot protocol for the synthesis of 2,5-disubstituted oxazoles from 1-aryl-2-nitroethanones was reported. In the presence of iron/AcOH in acetonitrile, the reaction of 1-aryl-2-nitroethanones with trimethyl orthoacetate or trimethyl orthobenzoate delivered the corresponding 2,5-disubstituted oxazoles in moderate to good yields.
基金supported by NSFC (No. 21276068)Department of Science and Technology Foundation of Hunan Province (No. 2010SK2001)Hunan Natural Science Foundation (No. 11JJ5008)
文摘Nine 5-aryl-2-methyloxazole derivatives were synthesized via gold-catalyzed alkyne oxidation. All of the compounds have been screened for their antiproliferative activities against MCF-7 cell （human breast carcinoma）, A549 cell （human lung carcinoma） and Hela cell （human cervical carcinoma） lines in vitro. The results revealed that compounds 1b, 1c and 1d exhibited strong inhibitory activities against the MCF-7 cell lines （with ICso values of 4.6, 9.7 and 2.2 μmol/L, respectively）.
基金Project supported by the National Natural Science Foundation of China （Nos. 20872088, 21072126）, the Leading Academic Discipline Projects of Shanghai Municipal Education Commission （No. J50102） and the Graduated Student Innovation Fund of Shanghai University （No. SHUCX 112034）
文摘In the presence of Cu（OAc）2·H2O, a variety of 5-trifluoromethyl-2,4-disubstituted oxazoles were easily synthesized via t-BuOOH （TBHP）/I2-mediated tandem oxidative cyclization from readily available starting materials aryl methanamines and α-trifluoroacetyl-substituted ketones or esters under mild conditions, The mechanism was proposed.
文摘以L-丝氨酸、L-丙氨酸和L-苏氨酸为起始原料,采用两种不同的方法分别合成了天然海洋化合物Leucam ide A的关键中间体口恶唑化合物Ⅰ及甲基口恶唑化合物Ⅱ。甲酯保护的L-丝氨酸和叔丁氧羰基保护的L-丙氨酸为原料,以N,N′-二环己基碳二亚胺(DCC)为缩合试剂,1-羟基苯并三氮唑(HOB t)为助剂,三乙胺为碱,缩合得到二肽后,利用Burgess试剂关环成口恶唑啉,再以1,8-二氮杂二环[5.4.0]十一烷-7-烯(DBU)和B rCC l3进行氧化脱氢,得到口恶唑化合物Ⅰ,收率为47.8%。甲基口恶唑化合物Ⅱ是以L-丝胺酸和L-苏氨酸为起始化合物。L-丝胺酸经甲酯化,叔丁氧羰基保护氨基后,以2,2-二甲氧基丙烷进行羟基和氨基的双保护,脱甲酯得到Garner酸,再与甲酯保护的L-苏氨酸缩合得到二肽。利用Dess-M artin Period inane试剂氧化其中的仲羟基,以三苯基膦和碘为试剂关环得到甲基口恶唑Ⅱ,反应收率46.1%。目标化合物及中间体结构经NMR进行了鉴定。
文摘The purification of 4,5-diphenyl-2-methyloxazole preparation was improved.Influences of concentration and solvent on the fluorescent property of 4,5-diphenyl-2-methyloxazole and 4,5-diphenyl-2-styryloxazole were studied,and fluorescence quantum yield(Φ)of the two compound were also studied in the paper.
