Acid catalyzed reactions of α,β-unsaturated aldehydes and ethyl diazoacetate

The formation of cyclopropanes from α,β-unsaturated aldehydes and diazo compounds has been a rather challenging goal due to the extremely reactive aldehyde starter. Herein, our group reports the first formation of ethyl 2-formyl-1-cyclopropanecarboxylate in 100% yield from the acid catalyzed reaction between acrolein and ethyl diazoacetate (EDA).     

Novel hexadentate imidazolium salts in the rhodium-catalyzed addition of arylboronic acids to aldehydes

Four novel hexadentate imidazolium salts were synthesized from hexakis(bromomethyl)benzene and 1-substituted imidazole. The arylation of aldehydes with arylboronic acids was effected conveniently and in high yields by a catalyst system generated in situ from these hexadentate imidazolium salts, [Rh(COD)Cl]₂ and a base.     

Direct synthesis of Cbz-protected β-amino ketones by iodine-catalyzed three-component condensation of aldehydes, ketones and benzyl carbamate

Iodine has been found to be very effective catalyst for a Mannich reaction between an aryl aldehyde, an aryl ketone and benzyl carbamate, even though this is a less reactive amine, to produce Cbz-protected β-aryl β-amino carbonyl compounds in high yields.     

Application of enzyme-field effect transistor sensor arrays as detectors in a flow-injection analysis system for simultaneous monitoring of medium components. Part II. Monitoring of cultivation processes

Glucose, maltose, sucrose, lactose, ethanol and urea concentrations were monitored simultaneously during the cultivation of Escherichia coli and Saccharomyces cerevisiae by means of enzyme field effect transistors (EnFETs) applying glucose dehydrogenase (GDH), maltase (MAL)/GDH, invertase (INV)/GDH, β-galactosidase (β-GAL)/galactosedehydrogenase (GALDH), alcoholdehydrogenase (ADH)/aldehydedehydrogenase (ALDH), and urease. These enzymes were (co)immobilized on the pH sensitive gates of an eight-FET array. The FET array was integrated in a commercial FIA system.     

A facile non-oxidative method for synthesizing 1,3-disubstituted pyrroles from pyrrolidine and aldehydes

Reactions of pyrrolidine with 2 equiv of aldehydes without any catalyst in a pressurized vessel at 140–200 °C yielded 1,3-disubstituted pyrroles. -Branched aldehydes gave fairly good yields of the corresponding products by this method, which provides a facile non-oxidative procedure for synthesizing 1,3-dialkylpyrroles from inexpensive pyrrolidine and aldehydes.     

Efficient conjugation and preferential DNA binding of oligonucleotides containing 2′-O-(2-oxoethyl)arabinouridine

Oligodeoxyribonucleotides were synthesized that contain a novel nucleoside, 2′-O-(2-oxoethyl)arabinouridine. Whereas such oligonucleotides showed only a slight reduction in the T_M values of their complexes with complementary DNA, a significant destabilization was observed in the case of duplexes formed with RNA. This may be explained by the C_2′-endo conformation of 2′-O-(2,3-dihydroxypropyl)arabinouridine as demonstrated by NMR experiments in D₂O. The modified oligonucleotides were used to synthesize a number of conjugates with dyes, biotin and a N-modified laminin peptide, by hydrazone and oxime formation. We suggest that the 2′-arabinoaldehyde-containing DNA duplexes may be valuable tools for affinity modification of DNA-binding proteins.     

烯丙基碘和锡与醛的选择加成反应

含活性基团的醛可与烯丙碘和锡粉直接进行亲核加成反应，得到高烯丙基的醇，水的存在不利于此反应的进行，与烯丙基溴相比，烯丙基碘反应活性更强，可在短时间内得较高的产率。     

Aminoalkylation with Aldehydes Mediated by Solid Lithium Perchlorate

Summary. The solid LiClO₄-mediated one-pot reaction of aldehydes with secondary amines and C nucleophiles afforded the corresponding aminoalkylation products in high yields. Unlike the previous reported procedure, the aminoalkylation of aldehyde was achieved in the presence of only 0.5 equivalents of solid lithium perchlorate in dichloromethane as the solvent with good to high yields at room temperature.     

Reactions of Cyanomethanesulfonamides with Aldehydes and Synthesis of 2-Benzyl-2,3-dihydrobenzopyrano[3,2-e] [1,2,4]thiadiazine 1,1-Dioxides

Summary.  Reactions of cyanomethanesulfonamides with aromatic aldehydes in the presence of AcOH and piperidine produced the addition products, the 1-cyano-2-arylethenesulfonamides, whereas reactions with benzonitrile yielded the 2-amino-1-cyano-2-phenylethenesulfonamides only when done in THF with BuLi. No addition products were isolated from the analogue reactions with 2-hydroxybenzaldehyde (salicylaldehyde). Instead, we obtained 2-imino-2H-chromene-3-sulfonamides with good to excellent yields. These 2H-chromene derivatives allowed a number of transformations, from which the reactions with orthoformates opened an approach to the hitherto unknown benzopyrano[3,2-e] [1,2,4]thiadiazine ring system.