Pummerer Type Research Articles

Synthesis of N-alkylated 2-pyridones through Pummerer type reactions of activated sulfoxides and 2-fluoropyridine derivatives.

N-Alkylated 2-pyridone products were obtained in good to excellent yields through a one-pot procedure involving either normal or interrupted Pummerer reactions between triflic anhydride activated sulfoxides and 2-fluoropyridine derivatives, followed by hydrolysis. This is a rare case that uses 2-fluoropyridine as a nucleophile in Pummerer type reactions.

Copper-catalyzed Pummerer type reaction of α-thio aryl/heteroarylacetates: Synthesis of aryl/heteroaryl α-keto esters

A copper catalyzed Pummerer type reaction of α-thio aryl/heteroarylacetates is described for the first time. This transformation represents a new route to synthesize α-keto esters, which are important intermediates for pharmaceuticals and organic synthesis. The reaction proceeds via in situ generation of a thionium ion that undergoes hydrolysis to furnish α-keto esters in synthetically viable yields (up to 82%).

Design, synthesis, and anticancer activity of C8-substituted-4′-thionucleosides as potential HSP90 inhibitors

A series of C8-substituted-4′-thioadenosine analogs 3a–3g, 15, and 17 and their truncated derivatives 4a–4j, 23–25, and 27 have been successfully synthesized from d-ribose and d-mannose, respectively, employing Pummerer type or Vorbrüggen condensation reactions and the functionalization at the C8-position of nucleobase via Stille coupling or nucleophilic aromatic substitution reactions as key steps. All the synthesized compounds were assayed for their HSP90 inhibitory activity, but they were found to be inactive up to 100μM. However, the 8-iodo derivatives 15, 17, and 27 exhibited potent anticancer activity, indicating that different mechanism of action might be involved in their biological activity.

ChemInform Abstract: Synthesis of 2‐Alkylidene‐3,1‐benzoxathiin‐4‐ones by the Pummerer Type Reaction

AbstractReview: 3 refs.

Synthesis of 2-Alkylidene-3,1-Benzoxathiin-4-Ones by the Pummerer Type Reaction

GRAPHICAL ABSTRACT

ChemInform Abstract: New Carbon-Carbon Bond Formation by the Pummerer Type Reaction of Vinylic Sulfoxides with Allylmagnesium Bromide.

ChemInform Abstract: New Carbon-Carbon Bond Formation by the Pummerer Type Reaction of Vinylic Sulfoxides with Allylmagnesium Bromide.

ChemInform Abstract: Highly Enantioselective Construction of a Quaternary Carbon Centre by the Pummerer Type Reaction: A Total Synthesis of (-)-Sibirine.

Highly enantioselective quaternary carbon formation (96% enantiomeric excess) is achieved by the Pummerer-type reaction of a chiral vinylic sulphoxide with allylmagnesium bromide; this method is applied to the synthesis of (–)-sibirine.

ChemInform Abstract: Synthesis of Aspidospermidine Alkaloids from 1,2,3,4-Tetrahydrocarbazole: Total Stereoselective Synthesis of (.+-.)-18-Noraspidospermidine.

Abstract The reactivity of the 1,2,3,4-tetrahydrocarbazol-4-one derivatives has been analysed and applied to the synthesis of (±)-18-noraspidospermidine (1b). This was synthesised, starting from 4-(1′,3′-dioxolan-2′-yl)cyclohexanone which was successively transformed to 3-methyl-3-(3′-nitropropyl)-1,2,3,4-tetrahydrocarbazol-4-one and to the imine tetracycle 13 by means of nickel boride catalyst. The reduction of 13 to the natural cis D ring junction was carried out with the LiAlH 4 AlCl 3 system. The construction of the E-ring was carried out by a Pummerer type reaction from thecis-7-tosyl-1-phenylthioacetamide derivative 17 by oxidation followed by intramolecular cyclisation, desulfurization and reduction to 1b.

Use of 3-(4-hydroxyphenyl)propionic acid as electron donating compound in a potentiometric aflatoxin M 1-immunosensor

We developed a potentiometric aflatoxin M 1-immunosensor which utilizes 3-(4-hydroxyphenyl)propionic acid (p-HPPA) as electron donating compound for horseradish peroxidase (HRP; EC 1.11.1.7). The assay system consists of a polypyrrole-surface-working electrode coated with a polyclonal anti-M 1 antibody (pAb–AFM 1), a Ag/AgCl reference electrode and a HRP–aflatoxin B 1 conjugate (HRP–AFB 1 conjugate). To optimize the potentiometric measuring system p-HPPA as well as related compounds serving as electron donating compounds were compared. Also the influence of different buffer systems, varying pH and substrate concentrations on signal intensity was investigated. Our results suggest that reaction conditions that favor the formation of Pummerer's type ketones lead to an increase in signal intensity rather than formation of fluorescent dye. Comparison with commercial ready-to-use HRP electron donating compounds such as 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), o-phenylenediamine (OPD) or 3,3′,5,5′-tetramethylbenzidine (TMB) showed that only 34%, 77% and 49% of the signal intensity of p-HPPA were reached, respectively. The optimized assay had a detection limit of 40 pg mL −1 and allowed detection of 500 pg mL −1 (FDA action limit) aflatoxin M 1 (AFM 1) in pasteurized milk and UHT-milk containing 0.3–3.8% fat within 10 min without any sample treatment. The working range was between 250 and 2000 pg mL −1 AFM 1.

Development of next generation 4'-selenonucleosides

Next generation 4'-selenonucleosides as potential antiviral and antitumor agents were synthesized using a Pummerer type condensation as a key step.

Design and synthesis of novel 2′,3′-dideoxy-4′-selenonucleosides as potential antiviral agents

On the basis of potent anti-HIV activity of 2’,3’-dideoxynucleosides (ddNs), their bioisosteric analogues, 2’,3’-dideoxy-4’-selenonucleosides (4’-seleno-ddNs) were first synthesized from a chiral template, d-glutamic acid using stereoselective ring-closure reaction of the dimesylate with Se 2− and Pummerer type condensation of the selenoxide with nucleobases as key steps. X-ray crystallographic analysis indicated that 4’-seleno-ddNs adopted the same C2’-endo/C3’-exo (South) conformation as anti-HIV active ddNs, but did not show anti-HIV activity, indicating that RT seems to prefer the C2’-exo/C3’-endo (North) conformation on binding with their triphosphates.

Role of Temperature in Suppression of the Formation of Pummerer's Type Ketone in Enzymatic Polymerization of 4-Propylphenol: An in-Situ Variable Temperature 1H NMR Study

Role of Temperature in Suppression of the Formation of Pummerer's Type Ketone in Enzymatic Polymerization of 4-Propylphenol: An in-Situ Variable Temperature ¹H NMR Study

Synthesis of Tetrahydrofurans via Silicon‐Promoted Pummerer Type Reaction.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of tetrahydrofurans via silicon promoted Pummerer type reaction

A novel, unprecedented transformation of δ-hydroxysulfoxides into substituted tetrahydrofurans by a silicon promoted Pummerer type reaction is disclosed. The transformation is shown to be general and is brought about under very mild reaction conditions. The products with the sulfide group at the anomeric carbon provide a suitable handle to carry out further transformations.

ChemInform Abstract: Domino Michael-Seleno Pummerer Type Reaction (Additive Seleno Pummerer Reaction).

Domino Michael–seleno Pummerer type reaction (additive seleno Pummerer type rearrangement) has been realised by the reaction of 1,3-dicarbonyl compounds with vinyl selenoxides in the presence of amine and chlorosilane.

ChemInform Abstract: Highly Stereoselective Synthesis of Enantiomerically Pure β-Hydroxy-γ-sulfenyl-γ-butyrolactone by Asymmetric Pummerer Type Cyclization.

Abstract Enantiomerically pure t -butyl 4-sulfinyl-3-silyloxy-butanoate can be transformed stereoselectively in a Pummerer reaction with TFAA into the usual aldehyde or into a cis β-hydroxy-γ-sulfenyl-γ-butyrolactone. Experimental conditions allowing total control of the reaction in favor of either the aldehyde or the γ-butyrolactone are described. The corresponding methyl butanoate led, under the same conditions, only to the aldehyde.

Highly stereoselective synthesis of enantiomerically pure β-hydroxy-γ-sulfenyl-γ-butyrolactone by asymmetric Pummerer type cyclization

Enantiomerically pure t-butyl 4-sulfinyl-3-silyloxy-butanoate can be transformed stereoselectively in a Pummerer reaction with TFAA into the usual aldehyde or into a cis β-hydroxy-γ-sulfenyl-γ-butyrolactone. Experimental conditions allowing total control of the reaction in favor of either the aldehyde or the γ-butyrolactone are described. The corresponding methyl butanoate led, under the same conditions, only to the aldehyde.

Domino Michael–seleno Pummerer type reaction (additive seleno Pummerer reaction)

Domino Michael–seleno Pummerer type reaction (additive seleno Pummerer type rearrangement) has been realised by the reaction of 1,3-dicarbonyl compounds with vinyl selenoxides in the presence of amine and chlorosilane.

Synthesis of aspidospermidine alkaloids from 1,2,3,4-tetrahydrocarbazole: Total stereoselective synthesis of (±)-18-noraspidospermidine

The reactivity of the 1,2,3,4-tetrahydrocarbazol-4-one derivatives has been analysed and applied to the synthesis of (±)-18-noraspidospermidine ( 1b). This was synthesised, starting from 4-(1′,3′-dioxolan-2′-yl)cyclohexanone which was successively transformed to 3-methyl-3-(3′-nitropropyl)-1,2,3,4-tetrahydrocarbazol-4-one and to the imine tetracycle 13 by means of nickel boride catalyst. The reduction of 13 to the natural cis D ring junction was carried out with the LiAlH 4 AlCl 3 system. The construction of the E-ring was carried out by a Pummerer type reaction from the cis-7-tosyl-1-phenylthioacetamide derivative 17 by oxidation followed by intramolecular cyclisation, desulfurization and reduction to 1b.

Research on the correlation between the Pummerer reaction and penicillin biosynthesis (review)

Research on the correlation between the Pummerer reaction mechanism and β-lactam formation during penicillin biosynthesis is discussed based on our silicon-induced asymmetric Pummerer type reaction.