Direct diazo-transfer reaction on β-lactam: Synthesis and preliminary biological activities of 6-triazolylpenicillanic acids

Abstract

In this study we report the first example of a direct diazo-transfer reaction on readily available 6-aminopenicillanates to give 6-azidopenicillanates in high yield. Subsequent Cu(I)-catalyzed Huisgen cycloaddition between these 6-azidopenicillanates and assorted terminal alkynes facilely furnished 6-triazolylpenicillanic acids. Preliminary biological screening indicates that these triazolylpenicillanic acids possess low to moderate antibacterial activities.

A Flexible Porphyrin–Annulene Hybrid: A Nonporphyrin Conformation formeso‐Tetraaryldivacataporphyrin

“…1-(4-Methoxyphenyl)prop-2-yn-1-ol: The synthesis of 1-(4-methoxyphenyl)prop-2-yn-1-ol was based on a literature procedure involving commercially available 1-phenylprop-2-yn-1-ol. [48] Ethynylmagnesium bromide (12.0 mL, 0.5 m in THF, 6 mmol) was added to a solution of anisol aldehyde (0.6 mL, 5 mmol) in anhydrous THF (5 mL) at room temperature under nitrogen. The reaction mixture was stirred for 1 h, then quenched with water (100 mL) and extracted with CH 2 Cl 2 (100 mL).…”

“…The synthetic work is summarized in Scheme 3. [48][49][50] In fact, compound 3 Me proved to be not much more stable than 3 Ph , but was easier to purify. Both structures of 3 Ph and 19 Ph have the typical porphyrinic skeleton, with the butadiene fragments in an "out" conformation, which remains in contrast with the unorthodox structure of the parent 21,23-ditelluraporphyrin 18 Ph .…”

Synthesis of tartaric acid analogues of FR258900 and their evaluation as glycogen phosphorylase inhibitors

“…The DPM esters could be cleaved by using dry anisole-TFA reagent in dry CH 2 Cl 2 at room temperature. 25 Purification of the crude products by column chromatography (PhCH 3 :AcOH 3:1) gave 26-33 in good to excellent yields (Scheme 140 4). Hydrolysis of the methoxycarbonyl esters was achieved by using an aq solution of NH 3 in MeOH and the products 34-39 were isolated in good to excellent yields.…”

Diversity-Oriented Synthesis Based on the DPPP-Catalyzed Mixed Double-Michael Reactions of Electron-Deficient Acetylenes and β-Amino Alcohols

“…Although the syntheses of the acetylenes 2a , 2c , and 2e have been reported previously, the acetylenes 2b , 2d , and 2f were unknown. Employing the protocol established by Oyelere and Calieno [ 52 , 53 ], we obtained each of these propargyl ketones in good yield after: (i) treating the pertinent aldehyde with ethynylmagnesium bromide at 0 °C, slowly warming to ambient temperature, and then working-up the mixture after 4 h and (ii) oxidizing the resulting propargyl alcohol, without further purification, using Jones reagent.…”