Particle size effect in the mechanically assisted synthesis of β-cyclodextrin mesitylene sulfonate

• Stéphane Menuel,
• Sébastien Saitzek,
• Eric Monflier and
• Frédéric Hapiot

Beilstein J. Org. Chem. 2020, 16, 2598–2606, doi:10.3762/bjoc.16.211

• . While the deprotonation/protonation equilibrium preferentially takes place at the 2- and 6-positions of the β-CD [29], the alkoxide located on the primary face at the 6-position is more inclined to react with the bulky mesitylenesulfonate group than the alkoxide on the secondary face at the 2-position

Preparation of 2-phospholene oxides by the isomerization of 3-phospholene oxides

• Péter Bagi,
• Réka Herbay,
• Nikolett Péczka,
• Zoltán Mucsi,
• István Timári and
• György Keglevich

Beilstein J. Org. Chem. 2020, 16, 818–832, doi:10.3762/bjoc.16.75

• -catalyzed reactions. Scheme 3 shows the computed reaction mechanism of the acidic transformation, which starts from the complex formed from MeSO3H and the 3-phospholene oxide 16A, involving in a protonation equilibrium with 16B. In the next step, the acid migrates to position C(4), and the olefinic carbon

Rational design of boron-dipyrromethene (BODIPY) reporter dyes for cucurbit[7]uril

• Mohammad A. Alnajjar,
• Jürgen Bartelmeß,
• Robert Hein,
• Pichandi Ashokkumar,
• Mohamed Nilam,
• Werner M. Nau,
• Knut Rurack and
• Andreas Hennig

Beilstein J. Org. Chem. 2018, 14, 1961–1971, doi:10.3762/bjoc.14.171

• encapsulation of the anchor group by CB7 has no effect on the spectroscopic properties of the dyes. At intermediate pH, the protonated fraction of the dye will be strongly bound by CB7, which affects the protonation equilibrium of the dye and leads to more protonated dye being produced. The net outcome is an

Equilibrium constants and protonation site for N-methylbenzenesulfonamides

• José A. Moreira,
• Ana M. Rosa da Costa,
• Luis García-Río and
• Márcia Pessêgo

Beilstein J. Org. Chem. 2011, 7, 1732–1738, doi:10.3762/bjoc.7.203

• parameter than with σ, which indicates that the initial protonation site is the oxygen atom of the sulfonyl group. Keywords: linear free-energy relationships; N-methylbenzenesulfonamides; protonation equilibrium; Introduction Having a knowledge of the protonation equilibrium constants for N

• structures, the latter having a greater relevance for the sulfonamides with electron-donor groups (Scheme 3). Conclusion The protonation equilibrium constants (pKBH+) for the para-substituted N-methylbenzenesulfonamides 3a–d in aqueous sulfuric acid were obtained from spectrophotometric measurements

• 97% (w/w). Plot of pKc against X for the protonation equilibrium of (circles) 3a, (squares) 3b, (triangles) 3c and (diamonds) 3d in aqueous sulfuric acid solutions. [X-MBS] = 5 × 10−5 M, 25 °C. Correlation between pKBH+ and (A) σ or (B) σ+ for compounds 3a–d. Reaction of N-methyl-N