The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed ...The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were determined.The results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest loss.Glucosone was the dominantα-DCs in RBP and the highest loss was observed after PVD.Aldehydes were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying methods.Comprehensively,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.展开更多
A one-pot synthesis of Hantzsch pyridines was achieved through NH4I-promoted condensation of 1,3-dicarbonyl compounds with DMSO and NH4OAc, in which the C4 of the pyridine rings was derived from DMSO and the nitrogen ...A one-pot synthesis of Hantzsch pyridines was achieved through NH4I-promoted condensation of 1,3-dicarbonyl compounds with DMSO and NH4OAc, in which the C4 of the pyridine rings was derived from DMSO and the nitrogen atom resulted from NH4OAc and NH4I. The target product could be obtained in moderate to excellent yields.展开更多
The asymmetric α-amination of 1,3-dicarbonyl compounds with dialkyl azodicarboxylates has been achieved by C2-symmetric BINOL-squaramide bearing multiple hydrogen bond donors to provide the desired products in excell...The asymmetric α-amination of 1,3-dicarbonyl compounds with dialkyl azodicarboxylates has been achieved by C2-symmetric BINOL-squaramide bearing multiple hydrogen bond donors to provide the desired products in excellent yields and enantioselectivities （up to 99% yield and 98% ee）.展开更多
基金supported by National Natural Science Foundation of China(Nos.31871861 and 31501548)The Apicultural Industry Technology System(NCYTI-43-KXJ17)The Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences(CAAS-ASTIP-2015-IAR)。
文摘The significant demand for high quality food has motivated us to adopt appropriate processing methods to improve the food nutritional quality and flavors.In this study,the effects of five drying methods,namely,pulsed vacuum drying(PVD),freeze drying(FD),infrared drying(IRD),hot-air drying(HAD)and sun drying(SD)on free amino acids(FAAs),α-dicarbonyl compounds(α-DCs)and volatile compounds(VOCs)in rape bee pollen(RBP)were determined.The results showed that FD significantly released the essential amino acids(EAAs)compared with fresh samples while SD caused the highest loss.Glucosone was the dominantα-DCs in RBP and the highest loss was observed after PVD.Aldehydes were the dominant volatiles of RBP and SD samples contained more new volatile substances(especially aldehydes)than the other four drying methods.Comprehensively,FD and PVD would be potential methods to effectively reduce the quality deterioration of RBP in the drying process.
基金We are grateful to the National Natural Science Foundation of China （Nos. 21572070 and 21172079）.
文摘A one-pot synthesis of Hantzsch pyridines was achieved through NH4I-promoted condensation of 1,3-dicarbonyl compounds with DMSO and NH4OAc, in which the C4 of the pyridine rings was derived from DMSO and the nitrogen atom resulted from NH4OAc and NH4I. The target product could be obtained in moderate to excellent yields.
基金the Fundamental Research Funds for the Central Universities (No.2042014kf0248) for support of this research
文摘The asymmetric α-amination of 1,3-dicarbonyl compounds with dialkyl azodicarboxylates has been achieved by C2-symmetric BINOL-squaramide bearing multiple hydrogen bond donors to provide the desired products in excellent yields and enantioselectivities （up to 99% yield and 98% ee）.
