Oximes of ketones and aldehydes are efficiently converted to the corresponding carbonyl compounds, using a combination of NaHSO4.H20 and paraformaldehyde in good to excellent yields under solid state conditions at roo...Oximes of ketones and aldehydes are efficiently converted to the corresponding carbonyl compounds, using a combination of NaHSO4.H20 and paraformaldehyde in good to excellent yields under solid state conditions at room temperature for 10 minutes.展开更多
Titanium silicalite (TS-1) without and with extra-framework titanium have been prepared and TiO_2 is also prepared under the same conditions.All the samples are characterized with XRD,FT-IR,and UV–Vis.The effects of ...Titanium silicalite (TS-1) without and with extra-framework titanium have been prepared and TiO_2 is also prepared under the same conditions.All the samples are characterized with XRD,FT-IR,and UV–Vis.The effects of extra-framework titanium in TS-1 on the ammoximation of cyclohexanone have been studied in a continuous slurry reactor.The characterization results reveal that the extra-framework titanium exists as anatase.The catalytic evaluation results show that the anatase has a positive effect on the ammoximation of cyclohexanone by extending the catalytic life because it also exhibits some activity,while the conversion of cyclohexanone and the selectivity to cyclohexanone oxime are not influenced.The anatase TiO_2 does not catalyze H_2O_2 decomposition appreciably compared with TS-1 without extra-framework titanium.The results are very useful in guiding the TS-1 production.展开更多
Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and...Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and conventional heating conditions. Acetylferrocene and acetophenone were subjected to oximation under the two conditions in various solvent mixtures, and the extent of conversion was determined by </span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">H nuclear magnetic resonance spectroscopy. Microwave irradiation was found to accelerate the rate of oximation of both acetylferrocene and acetophenone. Acceleration of the reaction under microwave irradiation was attributed to the efficient absorption of microwaves by the ferrocene nucleus.展开更多
Deoximation reaction is one of the most important transformations in organic synthesis and for fine chemical production.Since oximes are easily synthesized from carbonyl compounds and are stable compounds,this reactio...Deoximation reaction is one of the most important transformations in organic synthesis and for fine chemical production.Since oximes are easily synthesized from carbonyl compounds and are stable compounds,this reaction can be used for protection-deprotection,purification,and characterization of carbonyl compounds in organic synthesis,especially for the synthesis of medicines as well as the natural products.Moreover,because many oximes can be synthesized from non-carbonyl starting materials,the deoximation reaction is also widely used in the production of many carbonyl-contained fine chemicals.Deoximation methods by using stoichiometric reagents are mature and can produce the related carbonyl products in very high yield with broad substrate application scopes.But for environment-protection consideration as well as the production cost controlling purpose in fine chemical industry,developing catalytic deoximation methods is the trend of the field and there are a series of references on this topic in recent years.This short review summarized recent advances on the development of deoximation methods from stoichiometric reaction to catalytic reaction and the mechanisms of some important transformations were discussed in detail for reader reference.展开更多
Deoximation in metal chloride ionic liquids based on 1-alkyl-3-methylimidazolium and triethylene ammonium cations, such as AmimBr(Cl)-MClx (A=ethyl, butyl, benzyl; M=Al, Fe, Cu, Sn and Zn; x=2, 3) and Et3NHCl-FeCl...Deoximation in metal chloride ionic liquids based on 1-alkyl-3-methylimidazolium and triethylene ammonium cations, such as AmimBr(Cl)-MClx (A=ethyl, butyl, benzyl; M=Al, Fe, Cu, Sn and Zn; x=2, 3) and Et3NHCl-FeCl3 were investigated under mild conditions. Ferrate chloride ionic liquid was proved to be an effective catalyst for deoximation of cyclohexanone oxime, exhibiting high conversion of oximes and selectivity to cyclo- hexanone. Good performance for the deoximation of other oximes such as salicylald oxime, acetone oxime, benzo- phenone oxime, 4-nitrobenzald oxime, acetophenone oxime, 2-chlorobenzaldehyde oxime, Acetald oxime, 2-butanone oxime and (1R)-camphor oxime was also achieved with bmimBr-FeCl3 as catalyst and solvent. The de- oximation was determined to carry out via acid-catalytic hydrolysis and the reaction mechanism was proposed.展开更多
A variety of aldoximes and ketoximes were oxidized to corresponding aldehydes and ketones by nitric oxide in the presence of oxygen. A presumed mechanism was suggested.
Caprolactam, which is mainly produced via the Beckmann rearrangement reaction, is an important chemical material. The strict specifications of caprolactam products make the refining process of caprolactam extremely im...Caprolactam, which is mainly produced via the Beckmann rearrangement reaction, is an important chemical material. The strict specifications of caprolactam products make the refining process of caprolactam extremely important. According to the different rearrangement process, the refining process of caprolactam is also different. The main refining sequence of liquid phase rearrangement products includes extraction, ion exchange, hydrogenation, and distillation. The refining process of gas phase rearrangement products is conducted mainly through distillation, crystallization, and hydrogenation. In this paper, the research progress of caprolactam refining technology will be summarized according to different rearrangement reaction processes, which will provide a reference for the selection of appropriate caprolactam refining process.展开更多
A wide variety of aldoximes and ketoximes were regenerated to corresponding carbonyl compounds with Al(NO3)3·9H2O in presence of catalytic amounts of NaBr in CH2Cl2 at room temperature.
Under mild conditions, conversion of a variety of ketoximes and aldoximes to their corresponding amides and nitriles proceeded in the presence of PEG-SO3H with high yields.
The crystal structure of the title compound (C18H18N4O, Mr = 306.36) has been determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P1 with α = 4.783(0), b = 13.577(1), c = 13...The crystal structure of the title compound (C18H18N4O, Mr = 306.36) has been determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P1 with α = 4.783(0), b = 13.577(1), c = 13.830(1) A, α = 63.581(2), β = 88.326(2), γ = 86.161(2)°, V= 802.5(1) A3, Z= 2, Dc = 1.268 g/cm^3, F(000) = 324, μ(MoKa) = 0.082 mm^-1, the final R = 0.0497 and wR = 0.1199 for 3094 observed reflections (I 〉 2σ(I)). The dihedral angles between the phenyl (C(1)-C(4)-(6)) and triazole, the phenyl (C(13)-C(15)-C(18)) and triazole, and the two phenyl rings are 7.9(1), 69.9(1) and 67.8(1)°, respectively. Strong C-H…π interaction joins molecules into a chain along the c axis and contributes to the stability of the structure. Preliminary bioassay results show that the title compound possesses excellent and selective fungicidal activity against Colletotrichum gossypii but displays moderate to weak insecticidal activity against aphides.展开更多
Six Brnsted acidic ionic liquids(ILs) 1a―1f were synthesized and used as the dual solvent-catalyst systems for Beckmann rearrangement reactions. Among ILs 1a―1f, IL 1a exhibited the highest catalytic activity and ...Six Brnsted acidic ionic liquids(ILs) 1a―1f were synthesized and used as the dual solvent-catalyst systems for Beckmann rearrangement reactions. Among ILs 1a―1f, IL 1a exhibited the highest catalytic activity and successfully catalyzed the Beckmann rearrangement of ketoximes, and the corresponding amides were obtained in good to excellent yields(74%―92%). In addition, IL 1a could be recovered easily and reused at least three times without any loss of catalytic activity.展开更多
A pair of E/Z-isomers of 2-phenyl-6,7-dihydrobenzofuran-4(5H)-one O-cyanomethyl oxime,C16H14N2O2,as potential drugs for treating peptic ulcer and other acid-related diseases have been synthesized and characterized b...A pair of E/Z-isomers of 2-phenyl-6,7-dihydrobenzofuran-4(5H)-one O-cyanomethyl oxime,C16H14N2O2,as potential drugs for treating peptic ulcer and other acid-related diseases have been synthesized and characterized by IR,MS and NMR spectra.Meanwhile,the crystal of IIIa was obtained and determined by X-ray single-crystal diffraction.Crystal data: monoclinic system,space group P21 /c,a = 8.423(8),b = 19.596(16),c = 8.770(8),β = 107.750(12)°,V = 1379(2)3,Z = 4,F(000) = 560,Dc = 1.283 g/cm3,μ = 0.086 mm 1,R = 0.0681 and wR = 0.2029 for 14472 independent reflections(Rint = 0.0782) and 2428 observed ones(I 2σ(I)).展开更多
Acetophenone oxime and benzaldehyde oxime were converted to oxime ethers in the presence of alkyl halide or methyl sulfate and KOH in aqueous DMSO in 5 to 70 min. The yields of oxime ethers were 70 - 96%.
HNPC-A9908 (o-(3-phenoxybenzyl)-2-methylthio-1-(4-chlorophenyl) propyl ketone oxime), a novel oxime insecticide, is a highly effective and broad-spectrum insecticide which can be widely used to control many spec...HNPC-A9908 (o-(3-phenoxybenzyl)-2-methylthio-1-(4-chlorophenyl) propyl ketone oxime), a novel oxime insecticide, is a highly effective and broad-spectrum insecticide which can be widely used to control many species of foliar insects on various crops. A study was conducted to evaluate the fate of HNPC-A9908 and study the degradation dynamics of HNPC-A9908 residue in vegetable field ecosystem. The results showed that degradation of HNPC-A9908 was much faster in vegetable pakchoi than in soil, and its half-life in pakchoi and soil was 1.32 and 3.75 d, respectively. The final residue of HNPC-A9908 in pakchoi was at the undetectable level to 0.122 mg/kg. As a conclusion, a dosage of 90 g/hm^2 was suggested and considered to be safe to human beings and animals.展开更多
Dioxane-NO2 was employed to oxidize oximes to corresponding aldehydes and ketones in high yield in nonaqueous condition at room temperature. Thr reaction proved to be mild and selective.
A convenient synthesis of 1-alkyl-2-chloro-1H-indole-3-carbaldehyde oximes(5a―5d) and 1-alkyl-2-phenoxy-1H-indole-3-carbaldehyde oximes(6a―6d) from 2-indolone was completed via the Vilsmeier-Haack reac-tion,with...A convenient synthesis of 1-alkyl-2-chloro-1H-indole-3-carbaldehyde oximes(5a―5d) and 1-alkyl-2-phenoxy-1H-indole-3-carbaldehyde oximes(6a―6d) from 2-indolone was completed via the Vilsmeier-Haack reac-tion,with N-alkylation and oximation as the key steps.An improved one-pot method for the synthesis of 1-alkyl-2-alkoxy-1H-indole-3-carbaldehyde oximes(7a―7h) from 1-alkyl-2-chloro-1H-indole-3-carbaldehydes(3a―3d) was described.The Williamson reactions and esterification reactions were performed and the oxime-ethers and oxime-esters were synthesized,respectively.The new synthesized compounds(3a―11d) were characterized by 1H NMR,IR,MS,and elemental analysis.展开更多
AIM:To evaluate inflammatory activity in patients with Crohn's disease (CD) using technetium-99m-hexamethylpropyleneamine oxime (99mTc-HMPAO) granulocyte scintigraphy.METHODS: Twenty patients (7 male and 13 female...AIM:To evaluate inflammatory activity in patients with Crohn's disease (CD) using technetium-99m-hexamethylpropyleneamine oxime (99mTc-HMPAO) granulocyte scintigraphy.METHODS: Twenty patients (7 male and 13 female) with CD and five healthy volunteers were selected for 99mTc-HMPAO granulocyte scintigraphy. The Crohn's Disease Activity Index (CDAI), blood tests and C-reactive protein (CRP) of each patient were performed 7 d before the scintigraphic images. The leukocytes were labeled according to the International Society of Radiolabeled Blood Elements (ISORBE) consensus protocol and the scintigraphic images, including single photon emission computed tomography, were obtained 30 min and 2 h after injection of the radiolabeled leukocytes.RESULTS:The labeling yield of the leukocytes with the lipophilic complex 99mTc-HMPAO was 55.0%±10%. Six of the 20 patients (30%) presented congruent results for the three parameters investigated (CDAI, Scintigraphic Index and CRP). On the other hand, 14 patients (70%) did not show congruent results. There was no significant correlation between the indices analyzed according to the Spearman test (P>0.05,n=20).CONCLUSION: The results suggest that 99mTc-HMPAO-labeled leukocyte scintigraphy could be important for determining inflammatory activity in CD even in the absence of clinical symptoms.展开更多
文摘Oximes of ketones and aldehydes are efficiently converted to the corresponding carbonyl compounds, using a combination of NaHSO4.H20 and paraformaldehyde in good to excellent yields under solid state conditions at room temperature for 10 minutes.
基金was supported by the National Basic Research Program of China(‘‘973’’Program,No.G2000048005)the National Natural Science Foundation of China(No.21276183)
文摘Titanium silicalite (TS-1) without and with extra-framework titanium have been prepared and TiO_2 is also prepared under the same conditions.All the samples are characterized with XRD,FT-IR,and UV–Vis.The effects of extra-framework titanium in TS-1 on the ammoximation of cyclohexanone have been studied in a continuous slurry reactor.The characterization results reveal that the extra-framework titanium exists as anatase.The catalytic evaluation results show that the anatase has a positive effect on the ammoximation of cyclohexanone by extending the catalytic life because it also exhibits some activity,while the conversion of cyclohexanone and the selectivity to cyclohexanone oxime are not influenced.The anatase TiO_2 does not catalyze H_2O_2 decomposition appreciably compared with TS-1 without extra-framework titanium.The results are very useful in guiding the TS-1 production.
文摘Microwave-assisted reactions are an environmentally friendly approach for synthesizing organic compounds. In this study, oximation of acetylferrocene and acetophenone was conducted under both microwave irradiation and conventional heating conditions. Acetylferrocene and acetophenone were subjected to oximation under the two conditions in various solvent mixtures, and the extent of conversion was determined by </span><sup><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">H nuclear magnetic resonance spectroscopy. Microwave irradiation was found to accelerate the rate of oximation of both acetylferrocene and acetophenone. Acceleration of the reaction under microwave irradiation was attributed to the efficient absorption of microwaves by the ferrocene nucleus.
基金supported by National Key Research and Development Program of China (No. 2018YFD0200100)Natural Science Foundation of Guangling College (Key Project: No. ZKZD17005+4 种基金 major special project: No. ZKZZ18001)Natural Science Foundation of Jiangsu Province (No. BK20181449)Jiangsu Provincial Six Talent Peaks Project (No. XCL-090)Opening Foundation of the Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University (No. 2016GDGP0104)Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Deoximation reaction is one of the most important transformations in organic synthesis and for fine chemical production.Since oximes are easily synthesized from carbonyl compounds and are stable compounds,this reaction can be used for protection-deprotection,purification,and characterization of carbonyl compounds in organic synthesis,especially for the synthesis of medicines as well as the natural products.Moreover,because many oximes can be synthesized from non-carbonyl starting materials,the deoximation reaction is also widely used in the production of many carbonyl-contained fine chemicals.Deoximation methods by using stoichiometric reagents are mature and can produce the related carbonyl products in very high yield with broad substrate application scopes.But for environment-protection consideration as well as the production cost controlling purpose in fine chemical industry,developing catalytic deoximation methods is the trend of the field and there are a series of references on this topic in recent years.This short review summarized recent advances on the development of deoximation methods from stoichiometric reaction to catalytic reaction and the mechanisms of some important transformations were discussed in detail for reader reference.
基金Project supported by the Natural Science Foundation of Heilongjiang Province, China (Nos. ZD200820-01 and B200814).
文摘Deoximation in metal chloride ionic liquids based on 1-alkyl-3-methylimidazolium and triethylene ammonium cations, such as AmimBr(Cl)-MClx (A=ethyl, butyl, benzyl; M=Al, Fe, Cu, Sn and Zn; x=2, 3) and Et3NHCl-FeCl3 were investigated under mild conditions. Ferrate chloride ionic liquid was proved to be an effective catalyst for deoximation of cyclohexanone oxime, exhibiting high conversion of oximes and selectivity to cyclo- hexanone. Good performance for the deoximation of other oximes such as salicylald oxime, acetone oxime, benzo- phenone oxime, 4-nitrobenzald oxime, acetophenone oxime, 2-chlorobenzaldehyde oxime, Acetald oxime, 2-butanone oxime and (1R)-camphor oxime was also achieved with bmimBr-FeCl3 as catalyst and solvent. The de- oximation was determined to carry out via acid-catalytic hydrolysis and the reaction mechanism was proposed.
基金Project supported by the National Natural Science Foundation of China (No. 2967201)the Natural Science Foundation of Gansu Province
文摘A variety of aldoximes and ketoximes were oxidized to corresponding aldehydes and ketones by nitric oxide in the presence of oxygen. A presumed mechanism was suggested.
文摘Caprolactam, which is mainly produced via the Beckmann rearrangement reaction, is an important chemical material. The strict specifications of caprolactam products make the refining process of caprolactam extremely important. According to the different rearrangement process, the refining process of caprolactam is also different. The main refining sequence of liquid phase rearrangement products includes extraction, ion exchange, hydrogenation, and distillation. The refining process of gas phase rearrangement products is conducted mainly through distillation, crystallization, and hydrogenation. In this paper, the research progress of caprolactam refining technology will be summarized according to different rearrangement reaction processes, which will provide a reference for the selection of appropriate caprolactam refining process.
基金support for this work by the research facilities of Ilam University
文摘A wide variety of aldoximes and ketoximes were regenerated to corresponding carbonyl compounds with Al(NO3)3·9H2O in presence of catalytic amounts of NaBr in CH2Cl2 at room temperature.
基金support from the Natural Science Foundation of Gansu Province(No.3ZS061-A25-019)the Scientific Research fund of Gansu Provincial Education Department(No.0601-25)
文摘Under mild conditions, conversion of a variety of ketoximes and aldoximes to their corresponding amides and nitriles proceeded in the presence of PEG-SO3H with high yields.
基金Supported by NNSFC (20302002 and 20872046)the SRF for ROCS, SEM (No. [2007] 1108)
文摘The crystal structure of the title compound (C18H18N4O, Mr = 306.36) has been determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P1 with α = 4.783(0), b = 13.577(1), c = 13.830(1) A, α = 63.581(2), β = 88.326(2), γ = 86.161(2)°, V= 802.5(1) A3, Z= 2, Dc = 1.268 g/cm^3, F(000) = 324, μ(MoKa) = 0.082 mm^-1, the final R = 0.0497 and wR = 0.1199 for 3094 observed reflections (I 〉 2σ(I)). The dihedral angles between the phenyl (C(1)-C(4)-(6)) and triazole, the phenyl (C(13)-C(15)-C(18)) and triazole, and the two phenyl rings are 7.9(1), 69.9(1) and 67.8(1)°, respectively. Strong C-H…π interaction joins molecules into a chain along the c axis and contributes to the stability of the structure. Preliminary bioassay results show that the title compound possesses excellent and selective fungicidal activity against Colletotrichum gossypii but displays moderate to weak insecticidal activity against aphides.
基金Supported by the National Natural Science Foundation of China(Nos.20771030,20671025)
文摘Six Brnsted acidic ionic liquids(ILs) 1a―1f were synthesized and used as the dual solvent-catalyst systems for Beckmann rearrangement reactions. Among ILs 1a―1f, IL 1a exhibited the highest catalytic activity and successfully catalyzed the Beckmann rearrangement of ketoximes, and the corresponding amides were obtained in good to excellent yields(74%―92%). In addition, IL 1a could be recovered easily and reused at least three times without any loss of catalytic activity.
基金Supported by the National Natural Science Foundation of China(Nos.21102084,21272136,31070313)Scientific and Technological Research Project of Hubei Provincial Department of Education(No.Q20111210)Science Foundation of China Three Gorges University(No.KJ2010B001)
文摘A pair of E/Z-isomers of 2-phenyl-6,7-dihydrobenzofuran-4(5H)-one O-cyanomethyl oxime,C16H14N2O2,as potential drugs for treating peptic ulcer and other acid-related diseases have been synthesized and characterized by IR,MS and NMR spectra.Meanwhile,the crystal of IIIa was obtained and determined by X-ray single-crystal diffraction.Crystal data: monoclinic system,space group P21 /c,a = 8.423(8),b = 19.596(16),c = 8.770(8),β = 107.750(12)°,V = 1379(2)3,Z = 4,F(000) = 560,Dc = 1.283 g/cm3,μ = 0.086 mm 1,R = 0.0681 and wR = 0.2029 for 14472 independent reflections(Rint = 0.0782) and 2428 observed ones(I 2σ(I)).
文摘Acetophenone oxime and benzaldehyde oxime were converted to oxime ethers in the presence of alkyl halide or methyl sulfate and KOH in aqueous DMSO in 5 to 70 min. The yields of oxime ethers were 70 - 96%.
基金The National "Tenth-Five Year"Key Technologies R & D Program of China (No. 2001BA308A02-10, 2004BA308A21-4)
文摘HNPC-A9908 (o-(3-phenoxybenzyl)-2-methylthio-1-(4-chlorophenyl) propyl ketone oxime), a novel oxime insecticide, is a highly effective and broad-spectrum insecticide which can be widely used to control many species of foliar insects on various crops. A study was conducted to evaluate the fate of HNPC-A9908 and study the degradation dynamics of HNPC-A9908 residue in vegetable field ecosystem. The results showed that degradation of HNPC-A9908 was much faster in vegetable pakchoi than in soil, and its half-life in pakchoi and soil was 1.32 and 3.75 d, respectively. The final residue of HNPC-A9908 in pakchoi was at the undetectable level to 0.122 mg/kg. As a conclusion, a dosage of 90 g/hm^2 was suggested and considered to be safe to human beings and animals.
基金the National Natural Science Foundation of China and Henan Province Education Committee.
文摘Dioxane-NO2 was employed to oxidize oximes to corresponding aldehydes and ketones in high yield in nonaqueous condition at room temperature. Thr reaction proved to be mild and selective.
基金Supported by the Natural Science Foundation of Liaoning Province,China(No.202142037)
文摘A convenient synthesis of 1-alkyl-2-chloro-1H-indole-3-carbaldehyde oximes(5a―5d) and 1-alkyl-2-phenoxy-1H-indole-3-carbaldehyde oximes(6a―6d) from 2-indolone was completed via the Vilsmeier-Haack reac-tion,with N-alkylation and oximation as the key steps.An improved one-pot method for the synthesis of 1-alkyl-2-alkoxy-1H-indole-3-carbaldehyde oximes(7a―7h) from 1-alkyl-2-chloro-1H-indole-3-carbaldehydes(3a―3d) was described.The Williamson reactions and esterification reactions were performed and the oxime-ethers and oxime-esters were synthesized,respectively.The new synthesized compounds(3a―11d) were characterized by 1H NMR,IR,MS,and elemental analysis.
基金Supported by Fundao de Amparo a Pesquisa do Estado de Minas Gerais and Coordenao de Aperfeioamento de Pessoal de Nível Superior
文摘AIM:To evaluate inflammatory activity in patients with Crohn's disease (CD) using technetium-99m-hexamethylpropyleneamine oxime (99mTc-HMPAO) granulocyte scintigraphy.METHODS: Twenty patients (7 male and 13 female) with CD and five healthy volunteers were selected for 99mTc-HMPAO granulocyte scintigraphy. The Crohn's Disease Activity Index (CDAI), blood tests and C-reactive protein (CRP) of each patient were performed 7 d before the scintigraphic images. The leukocytes were labeled according to the International Society of Radiolabeled Blood Elements (ISORBE) consensus protocol and the scintigraphic images, including single photon emission computed tomography, were obtained 30 min and 2 h after injection of the radiolabeled leukocytes.RESULTS:The labeling yield of the leukocytes with the lipophilic complex 99mTc-HMPAO was 55.0%±10%. Six of the 20 patients (30%) presented congruent results for the three parameters investigated (CDAI, Scintigraphic Index and CRP). On the other hand, 14 patients (70%) did not show congruent results. There was no significant correlation between the indices analyzed according to the Spearman test (P>0.05,n=20).CONCLUSION: The results suggest that 99mTc-HMPAO-labeled leukocyte scintigraphy could be important for determining inflammatory activity in CD even in the absence of clinical symptoms.