Regioselective N-Addition/Substitution Reaction of α-Alkylidene Pyrazolinones with Propargyl Sulfonium Salts to Construct Allylthio-Containing Pyrazolones

Abstract

The regioselective N-addition/substitution reaction between α-alkylidene pyrazolinones and propargyl sulfonium salts has been developed to construct functionalized allylthio-containing pyrazolones with moderate to excellent yields. α-Alkylidene pyrazolinones act as N-nucleophilic agents which are distinguished from reported C-nucleophilic reactions. Excellent regioselectivity, readily available starting materials, the broad range of substrates, gram-scale synthesis, and simple operation illustrate the synthetic advantages of this new reaction pathway.

Combined inorganic base promoted N-addition/[2,3]-sigmatropic rearrangement to construct homoallyl sulfur-containing pyrazolones

“…Recently our group reported the first regioselective NaOAc·3H 2 O-promoted N-addition/substitution reaction between α-alkylidene pyrazolinones and propargyl sulfonium salts ( Scheme 1c ). 14 Accidentally, we found that strong inorganic bases can efficiently promoted the rearrangement of sulfur salts. Based on our processive interests on constructing functionalized pyrazolones and exploring the diverse reactive pathway of propargyl sulfonium salts, 9,15 we herein report the realization of regioselective NaOAc·3H 2 O/KOH-promoted N-addition/[2,3]-sigmatropic rearrangement reaction of α-alkylidene pyrazolinones and propargyl sulfonium salts, delivering bioactive homoallyl sulfur-containing pyrazolones in moderate to excellent yields ( Scheme 1d ).…”

1,3‐diarylpyrazolones as potential anticancer agents for non‐small cell lung cancer: Synthesis and antiproliferative activity evaluation

“…FT-IR: 692, 756, 1407, 1498, 1610, 1715, 2815, 2962 7, 119.2, 125.4, 126.1, 128.9, 129.0, 130.8, 138.2, 154.8, 170.3. FT-IR: 690, 756, 1118, 1331, 1458, 1496, 1595, 1716, 2952 (Shen et al, 2019) White crystals, MP: 152°C, 1 H NMR (400 MHz, CDCl 3 ): δ 3.81 (s, 2H), 7.48 (brs, 3H), 7.53 (d, 2H, J = 8.0 Hz), 7.75 (d, 2H, J = 4.0 Hz), 7.91 (d, 2H, J = 8.0 Hz). 13 C NMR (100 MHz, CDCl 3 ): δ 39.…”

“…HRMS (ESI) calcd for C 15 H 13 N 2 O (M + H + ), 237.1022; found, 237.1021. (Shen et al, 2019) White crystals, MP: 152°C, 1 H NMR (400 MHz, CDCl 3 ): δ 3.81 (s, 2H), 7.48 (brs, 3H), 7.53 (d, 2H, J = 8.0 Hz), 7.75 (d, 2H, J = 4.0 Hz), 7.91 (d, 2H, J = 8.0 Hz). 13 C NMR (100 MHz, CDCl 3 ): δ 39.…”

Divergent Domino Reactions of Prop-2-ynylsulfonium Salts: Access to Sulfur-Containing Benzo-Fused Dioxabicyclo[3.3.1]nonanes and Dihydrofuro[2,3-c]chromenes

“…Different from vinylsulfonium salts, prop-2-ynylsulfonium salts − could isomerize to allenic sulfonium salts under basic conditions and be attacked by a nucleophile at the β-carbon atom first. The obtained zwitterionic intermediate B and the resonance structure B′ can undergo a similar process to access α-regioselective intermediate C and γ-regioselective intermediate D .…”