The reductive coupling of enones or enals with alkynes, followed by olefin oxidative cleavage and Paal-Knorr cyclization, provides a versatile entry to a variety of pyrrole frameworks. A number of limitations of alternate entries to the requisite 1,4-dicarbonyl intermediate are avoided. Classes of pyrroles that are accessible by this approach include 2,3-, 2,4-, 1,2,3-, 1,2,4-, 2,3,5-, and 1,2,...

One pot syntheses of furan, thiophene, and pyrrole were accomplished by oxidative deacetylation using Mn(III)/Co(II) catalysts and the Paal-Knorr reaction from 1,5-dicarbonyl compounds, which are prepared from the conjugate addition of ethyl acetoacetate to α,β-unsaturated carbonyl compounds. The oxidative deacetylation and reductive cyclization of β-ketoesters derived from ethyl acetoacetate a...

The synthesis of new 3-heteroaryl-8-chloropyrazolo[5,1-c][1,2, 4]benzotriazine 5-oxides and their binding activities at the central benzodiazepine receptor (BZR) are reported. The derivatives substituted at the 3-position with electron-rich five-membered rings, such as pyrrole 11, 2-thiophene 13c, or 3-thiophene 13d, showed good affinity values for BZR. In in vivo tests the 3-(thien-3-yl)-8-chl...

The cationic ruthenium catalyst Ru(3)(CO)(12)/NH(4)PF(6) was found to be highly effective for the intermolecular coupling reaction of pyrroles and terminal alkynes to give gem-selective alpha-vinylpyrroles. The carbon isotope effect on the alpha-pyrrole carbon and the Hammett correlation from a series of para-substituted N-arylpyrroles (rho = -0.90) indicate a rate-limiting C-C bond formation s...

The paper describes the Suzuki cross-coupling of a variety of N and C-3 substituted 5-bromoindazoles with N-Boc-2-pyrrole and 2-thiopheneboronic acids. The reactions, performed in the presence of K(2)CO(3), dimethoxyethane and Pd(dppf)Cl(2) as catalyst, gave the corresponding adducts in good yields. The methodology allows the facile production of indazole-based heteroaryl compounds, a unique ar...

A new synthesis of the 20S proteasome inhibitor clasto-lactacystin beta-lactone is described. Our route to this important natural product involves the partial reduction of an electron deficient pyrrole as a key step. By judicious choice of enolate counterion, we were able to exert complete control over the stereoselectivity of the reduction/aldol reaction. Early attempts to complete the synthes...

W ithin the last years optically active oxazoline ligands have proven use in transition-metal catal­ ysed asymmetric synthesis. In copper-catalysed cy­ clopropanation reactions oxazolines turned out to be the ligands of choice [2, 3], Oxazolines substituted in 2-position with a heteroaromatic com pound such as pyridine [4] gave good results in many systems of asymmetric catalysis, e. g., in ena...

In the title compound, C(18)H(11)ClN(6), the pyrrole, pyrimidine and tetra-zole rings form a nearly planar fused trihetrocyclic system with an r.m.s. deviation of 0.0387 (13) Å, to which the 4-chloro-phenyl group and the phenyl group are substituted at the 7 and 9 positions, respectively. The dihedral angles between the pyrrole ring and the 4-chloro-phenyl and phenyl rings are 32.1 (4) and 7.87...

Indole is a benzopyrrole in which the benzene and pyrrole rings are fused through the 2-and 3-positions of the pyrrole nucleus. The indole derivatives are very much used as anticonvulsant agents. In the same context, several indole derivatives were prepared by the reaction between indole-3carboxaldehyde and various p-substituted phenylsemicarbazides, in the presence of glacial acetic acid. The ...