Mixtures of ethyl (E)- and (Z)-4-alkoxy-2-fluoro-3,4-diphenylbut-2-enoates (6–8) prepared from benzoin ethers and ethyl 2-(diethoxyphosphoryl)-2-fluoroacetate were transformed in high yields to the target 3-fluoro-4,5-diphenylfuran-2(5H)-one (14) using bromine in tetrachloromethane at room temp...

In the presence of TiCl4 the 4 position of the title silyl ester reacts with such electrophiles as allylic ethers or bromides carrying the leaving group on the secondary carbon without allylic rearrangement.

Z-Vinylic tellurides are prepared by stereoselective vinylic substitution on Z/E mixtures of enolphosphates, acetates, tosylates and triflates by organotellurolates. The reaction is sensitive to the nature of the organotellurolate; the aromatic derivatives react slower than the aliphatic ones. T...

Organopalladium halides, acetates, triflates and similar derivatives lacking β sp3-bonded hydrogens generally react easily with unhindered alkenes to form new alkenes in which an original, vinyl hydrogen is replaced by the organic group of the palladium reactant. The reactions occur in solution...

A novel asymmetric tandem transetherification–intramolecular hetero Diels–Alder reaction of methyl (E)-4-methoxy-2-oxo-3-butenoate with δ,ε-unsaturated alcohols has been found to be catalyzed by optically active complexes based on bis(oxazoline) (box) chiral ligands and copper(II) cations. T...

Vapor-liquid equilibrium data of hexamethyl disiloxane+vinyl acetate system at 101.3kPa were measured by using double circulating vapor-liquid equilibrium still. The thermodynamic consistency of the VLE data was examined by Herrington method. Experimental data was correlated by non-random two-li...

The palladium-catalyzed ring closure of ortho0iodophenyl 3-butenoate to 4-methylcoumarin is in competition with the isomerization to the 2-butenoic ester; the latter reaction has been controlled by the appropriate use of ligands, solvents and neutralizing agents to the point that quantitative yi...

An improved one-flask synthesis of various methyl 2-diazo-4-aryl and 4-heteroaryl-3-butenoates, precursors to donor/acceptor substituted carbenoids, is described. Their Rh2(S-DOSP)4 catalyzed reaction with 1-acetoxy-3,4-dihydronaphthalene, via a combined C–H activation/Cope rearrangement pathwa...

5-Diazomethyl-4-methoxycarbonyltriazoles are capable of undergoing ring-degenerate rearrangements (19 → 20) when a strong electron-withdrawing substituent (e.g. p-nitrophenyl or o,p-dinitrophenyl) is located at the N-1 position. Whereas the unrearranged diazomethyltriazole 19a decomposes therma...

Cancer procoagulant (CP) is a cysteine proteinase from cancer cells that initiates blood coagulation. Members of two classes of unique and highly specific cysteine proteinase inhibitors, peptidyl diazomethyl ketones (PDK) and peptidyl sulfonium salts (PSS), were studied to determine whether or n...

A series of cysteine diazomethyl- and chloromethyl ketone derivatives has been synthesized and evaluated against human B-lineage (Nalm-6) and T-lineage (Molt-3) acute lymphoblastic leukemia cell lines. The chloromethyl ketone compounds showed potent cytotoxicity against these cell lines, with IC...

Treatment of α,β-epoxy diazomethyl ketones 1a–h with SnCl4 in dichloromethane at −78°C leads to β-chloro-α-hydroxy diazoketones 3a–h in good yields. The opening of the epoxide ring takes place in a syn manner with retention of configuration at Cβ. The chloro hydroxy diazoketones 3 are co...

For the reaction between HCNN and NO, quantum-chemical calculations were performed at the level CCSD(T)/aug-cc-PVQZ//B3LYP/6-311++G(3df,2p), in conjunction with VTST and RRKM theory. Our results indicate that two favorable paths involve the formation of HNCO + N2 (P2) and of HCNO + N2 (P4). The ...

Benzyloxycarbonyl-phenylalanyl diazomethyl ketone and benzyloxy-carbonyl-phenylalanyl-phenylalanyl diazomethyl ketone, which have been shown to inactivate the thiol protease papain by a mechanism different from that of substrate chloromethyl ketone derivatives, have now been examined as inhibito...

Diazomethyl β-d-galactopyranosyl ketone (1) has been proven to be a mechanism-based, irreversible (suicide-substrate) inactivator of Aspergillus oryzae β-d-galactosidase, but not an inactivator of E. coli lacZ β-d-galactosidase. Compound 1 is stable in buffers of normal physiological pH. It i...

The diazomethyl (HCNN) radical has attracted considerable attention due to its great interest in interstellar chemistry and combustion processes. In this article, we have systemically studied the low-lying electronic states of the HCNN radical and its ions through complete active space self-cons...

The synthesis of two types of so far unknown title compounds is described. Carbene complexes LnMC(R)OSiR2C(N2)COOMe [LnM(OC)5W (3), (OC)5Cr (4), (OC)5Mo (5), (MeCp)(OC)2Mn (6)] were obtained from the corresponding acyl metalates by electrophilic (diazomethyl)silylation. Similarly, (diazo...

RésuméReaction of aldose derivatives with dimethyl(diazomethyl)phosphonate, generated in situ by methanolysis of dimethyl(1-diazo-2-oxopropyl)phosphonate, leads to glyco-1-ynitols derivatives. This synthesis presents two main advantages: it is a one-step synthesis, and tolerates free hydroxyl ...

6-O-Tosyl-d-glucal 1 upon treatment with excess LiAlH4 unexpectedly gave 3,6-anhydro-d-glucal 2 as a major product in good yield. A crystal structure was obtained. Reaction of the anhydride 2 with N-iodosuccinimide (NIS) in excess methanol resulted in the formation of diastereomeric 2-deoxy-2-io...

Starting from 1,2,4-tri-O-acetyl-3,6-anhydro-α-d-galactopyranose, 4-O-acetyl-3,6-anhydro-1,2-O-(1-cyanoethylidene)-α-d-galactopyranose (7) was synthesized by treatment with cyanotrimethylsilane. Additionally, 3,4-di-O-acetyl-1,2-O-(1-cyanoethylidene)-6-O-tosyl-α-d-galactopyranose was prepared...