A short and facile synthesis of a series of 1,2-dihydroquiazolin-4(3H)-ones was accomplished in good yields via novel reductive cyclization of o-nitrobenzamides with ketones promoted by TiCl4/Zn system. The structure ...A short and facile synthesis of a series of 1,2-dihydroquiazolin-4(3H)-ones was accomplished in good yields via novel reductive cyclization of o-nitrobenzamides with ketones promoted by TiCl4/Zn system. The structure was established on the basis of elemental analysis, IR, 1H NMR and confirmed by a single-crystal X-ray diffraction analysis. This method has the advantages of easily accessible starting materials, convenient manipulation and moderate to high yields.展开更多
An efficient synthesis of 2, 3-disubstituted indole derivatives through low-valent titanium induced reductive cyclization of acylamido carbonyl compounds is described.
Low-valent titanium reagent prepared from titanium tetrachloride and zinc was empolyed to induce the coupling reaction of thiocyanates with tetrahydrofuran yield alkyl 4-hydroxy butyl sulfide and isocyanate yield subs...Low-valent titanium reagent prepared from titanium tetrachloride and zinc was empolyed to induce the coupling reaction of thiocyanates with tetrahydrofuran yield alkyl 4-hydroxy butyl sulfide and isocyanate yield substituted urea.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 reductive coupling reactions of aryl sulfonyl chloride induced by (TiCl4-Zn) reagent affords diaryl disulfide. However, reaction of aryl sulfonyl chloride with α,β-unsaturated ester under the same condition affo...The reductive coupling reactions of aryl sulfonyl chloride induced by (TiCl4-Zn) reagent affords diaryl disulfide. However, reaction of aryl sulfonyl chloride with α,β-unsaturated ester under the same condition affords β-arylsulfo ester.展开更多
Treatment of acyl chlorides and diaryl ketones with an activated Ti(o)reagent,prepared by reduction of TiCl_4 with Zn powder,effects an intermolecular reductive cross-coupling reaction leading to ketones.
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
Double asymmetric Diels-Alder reaction of 1(SR)-p-Tolylsulfinyl-3-penten-2-one with cyclopentadiene using a chiral titanium reagent was performed. The diastereoselectivity dependent on the size of aryl substituent i...Double asymmetric Diels-Alder reaction of 1(SR)-p-Tolylsulfinyl-3-penten-2-one with cyclopentadiene using a chiral titanium reagent was performed. The diastereoselectivity dependent on the size of aryl substituent involved in the chiral ligands was discussed Absolute configuration of the cycloadducts was conformed. Dramatic reversal of selectivity is observed.展开更多
Synthesis of 3,3＇,4,4＇-tetrahydro-4,4＇-bibenzo[e][1,3]oxazine-2,2＇-diones via reaction of salicylidendphenylhy- drazone and triphosgene with the aid of low-valent titanium reagent is described. This method has the...Synthesis of 3,3＇,4,4＇-tetrahydro-4,4＇-bibenzo[e][1,3]oxazine-2,2＇-diones via reaction of salicylidendphenylhy- drazone and triphosgene with the aid of low-valent titanium reagent is described. This method has the advantages of accessible starting materials, good yields and short reaction time.展开更多
We report the concise and protecting-group-free enantioselective total syntheses of circumdatins F and H.In view of the extreme importance of analogs of quinazolinone alkaloids in drug research and discovery,four anal...We report the concise and protecting-group-free enantioselective total syntheses of circumdatins F and H.In view of the extreme importance of analogs of quinazolinone alkaloids in drug research and discovery,four analogs of bioactive quinazolinobenzodiazepine alkaloids,including demethoxycircumdatin H(12)and N-demethyl-benzomalvin A(13),have been synthesized.The method is based on the low-valent titanium-promoted intra-molecular reductive coupling of imides with o-nitrobenzimides,which yielded quinazolino[3,2-a][1,4]benzodi-azepines under mild conditions.In addition,heptacyclic dehydraasperlicin E(16)has been synthesized from asper-licin C by a NCS-mediated dehydra-cyclization reaction.展开更多
The surface organic modification of TiO2 particles with titanate coupling reagent,which was pre-coated with double layers of SiO2 and Al2O3,was studied.Experiments showed that the modified particles exhibited hydropho...The surface organic modification of TiO2 particles with titanate coupling reagent,which was pre-coated with double layers of SiO2 and Al2O3,was studied.Experiments showed that the modified particles exhibited hydrophobic characteristics.The modification state of the particle surface was characterized by IR spectroscopic measurement,pyrolytic gas chromatography,thermogravimetric analysis and X-ray photoelectron spectra.The titanate coupling reagent binding with the hydroxyl on the particle surface was analyzed.The surface characteristics of pre-modification and post-modification particles were compared.展开更多
基金Project supported by the Natural Science Foundation of Education Committee of Jiangsu Province (No. 03KJB150136).
文摘A short and facile synthesis of a series of 1,2-dihydroquiazolin-4(3H)-ones was accomplished in good yields via novel reductive cyclization of o-nitrobenzamides with ketones promoted by TiCl4/Zn system. The structure was established on the basis of elemental analysis, IR, 1H NMR and confirmed by a single-crystal X-ray diffraction analysis. This method has the advantages of easily accessible starting materials, convenient manipulation and moderate to high yields.
文摘An efficient synthesis of 2, 3-disubstituted indole derivatives through low-valent titanium induced reductive cyclization of acylamido carbonyl compounds is described.
文摘Low-valent titanium reagent prepared from titanium tetrachloride and zinc was empolyed to induce the coupling reaction of thiocyanates with tetrahydrofuran yield alkyl 4-hydroxy butyl sulfide and isocyanate yield substituted urea.
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 reductive coupling reactions of aryl sulfonyl chloride induced by (TiCl4-Zn) reagent affords diaryl disulfide. However, reaction of aryl sulfonyl chloride with α,β-unsaturated ester under the same condition affords β-arylsulfo ester.
文摘Treatment of acyl chlorides and diaryl ketones with an activated Ti(o)reagent,prepared by reduction of TiCl_4 with Zn powder,effects an intermolecular reductive cross-coupling reaction leading to ketones.
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Double asymmetric Diels-Alder reaction of 1(SR)-p-Tolylsulfinyl-3-penten-2-one with cyclopentadiene using a chiral titanium reagent was performed. The diastereoselectivity dependent on the size of aryl substituent involved in the chiral ligands was discussed Absolute configuration of the cycloadducts was conformed. Dramatic reversal of selectivity is observed.
基金Project supported by the National Natural Science Foundation of China （No. 21072144） and the Major Basic Research Project of the Natural Science Foundation of the Jiangsu Higher Education Institutions （No. 10KJAI50049）.
文摘Synthesis of 3,3＇,4,4＇-tetrahydro-4,4＇-bibenzo[e][1,3]oxazine-2,2＇-diones via reaction of salicylidendphenylhy- drazone and triphosgene with the aid of low-valent titanium reagent is described. This method has the advantages of accessible starting materials, good yields and short reaction time.
基金support from the National Natural Science Foundation of China(Nos.21332007 and 21472153)the Program for Changjiang Scholars and Innovative Research Team in University(PCSIRT)of Ministry of Education.
文摘We report the concise and protecting-group-free enantioselective total syntheses of circumdatins F and H.In view of the extreme importance of analogs of quinazolinone alkaloids in drug research and discovery,four analogs of bioactive quinazolinobenzodiazepine alkaloids,including demethoxycircumdatin H(12)and N-demethyl-benzomalvin A(13),have been synthesized.The method is based on the low-valent titanium-promoted intra-molecular reductive coupling of imides with o-nitrobenzimides,which yielded quinazolino[3,2-a][1,4]benzodi-azepines under mild conditions.In addition,heptacyclic dehydraasperlicin E(16)has been synthesized from asper-licin C by a NCS-mediated dehydra-cyclization reaction.
文摘The surface organic modification of TiO2 particles with titanate coupling reagent,which was pre-coated with double layers of SiO2 and Al2O3,was studied.Experiments showed that the modified particles exhibited hydrophobic characteristics.The modification state of the particle surface was characterized by IR spectroscopic measurement,pyrolytic gas chromatography,thermogravimetric analysis and X-ray photoelectron spectra.The titanate coupling reagent binding with the hydroxyl on the particle surface was analyzed.The surface characteristics of pre-modification and post-modification particles were compared.
