Comparison of zwitterionic N-alkylaminomethanesulfonic acids to related compounds in the Good buffer series

• Robert D. Long,
• Newton P. Hilliard Jr,
• Suneel A. Chhatre,
• Tatiana V. Timofeeva,
• Andrey A. Yakovenko,
• Daniel K. Dei and
• Enoch A. Mensah

Beilstein J. Org. Chem. 2010, 6, No. 31, doi:10.3762/bjoc.6.31

• were synthesized in aqueous solution by reaction of primary or secondary amines with formaldehyde/sodium hydrogensulfite addition compound. The pKa values of the ammonium ions of this series of compounds (compared to existing Good buffers) was found to correlate well with the length of the carbon chain

• approach previously reported in the literature for the specific synthesis of aminomethanesulfonates. In this approach amines are reacted with the product of addition of sodium hydrogensulfite to formaldehyde [9][10]. The sodium hydrogensulfite/formaldehyde addition product 7 (sodium hydroxymethanesulfonate

• solution titrimetry (min. 5 repetitions from low to high, then high to low pH) using standardized NaOH and HCl solutions. General synthetic procedure The compounds were prepared by dissolving 0.200 mol (26.8 g) of sodium hydrogensulfite-formaldehyde addition product in 250 mL deionized water in a 500 mL

A short synthesis of (±)-cherylline dimethyl ether

• Bhima Y. Kale,
• Ananta D. Shinde,
• Swapnil S. Sonar,
• Bapurao B. Shingate,
• Sanjeev Kumar,
• Samir Ghosh,
• Soodamani Venugopal and
• Murlidhar S. Shingare

Beilstein J. Org. Chem. 2009, 5, No. 80, doi:10.3762/bjoc.5.80

• moderate yield. Immediate reduction of the isocyanate 10 by lithium aluminium hydride in tetrahydrofuran gave N-methylamine 6 in 90% yield. The crude amine 6, on Pictet–Spengler reaction with formaldehyde in acetic acid, gave (±)-cherylline dimethyl ether [15] 5 in 45% yield. In short, we have devised a

• ). A mixture of 6 (2.0 g, 0.006 mol), formaldehyde (0.64 g, 0.007 mol) and acetic acid (5 mL) was stirred at 90 °C under nitrogen atmosphere for 2 h. After cooling to room temperature, the reaction mixture was basified using saturated NaHCO3 solution. This basified solution was extracted ethyl acetate

An expedient synthesis of 5-n-alkylresorcinols and novel 5-n-alkylresorcinol haptens

• Kirsti Parikka and
• Kristiina Wähälä

Beilstein J. Org. Chem. 2009, 5, No. 22, doi:10.3762/bjoc.5.22

• preparation of stilbenes from benzyltriphenylphosphonium salts and aryl aldehydes [30][31] and also include reactions of stabilized ylids with aryl aldehydes or short alkyl chain alkanals [32][33][34][35][36] and the preparation of o- and p-nitrostyrenes from the highly reactive formaldehyde [37]. To provide

Synthesis of methylenebisamides using CC- or DCMT- activated DMSO

• Qiang Wang,
• Lili Sun,
• Yu Jiang and
• Chunbao Li

Beilstein J. Org. Chem. 2008, 4, No. 51, doi:10.3762/bjoc.4.51

• ], hexamethylenetetramine [21] or activated DMSO [6], or by the reaction of nitriles with formaldehyde [22] or activated sulfoxides [23]. However, each method has certain limitations with regards to scope and reaction conditions, for example, longer reaction time [20], lower yield [6], purification problems [21][23] and

Expedient syntheses of the N-heterocyclic carbene precursor imidazolium salts IPr·HCl, IMes·HCl and IXy·HCl

• Lukas Hintermann

Beilstein J. Org. Chem. 2007, 3, No. 22, doi:10.1186/1860-5397-3-22

• behind such differences of the reaction outcome? To our knowledge, the mechanism of the Arduengo imidazolium salt synthesis has not been discussed in the literature. We propose that alkylation of the DADs A by formaldehyde and HCl (or TMSCl) leads to an iminium salt B (Scheme 2); analogous alkylations

• (Scheme 3a). [21] This is one potential side-reaction, but brown colored side-products can also derive from electrophilic aromatic alkylations of arylamine units by iminium salts from formaldehyde or protonated DADs (as in the bakelite reaction). Such side-reactions will be most prominent with DADs from