Synthesis of enantiomerically enriched (R)-¹³C-labelled 2-aminoisobutyric acid (Aib) by conformational memory in the alkylation of a derivative of L-alanine

• Stephen P. Fletcher,
• Jordi Solà,
• Dean Holt,
• Robert A. Brown and
• Jonathan Clayden

Beilstein J. Org. Chem. 2011, 7, 1304–1309, doi:10.3762/bjoc.7.152

• formation of pairs of diastereoisomeric dipeptides from small aliquots of 6* with an excess of Cbz-L-Phe, EDC and HOBt (Scheme 2). The ratio of diastereoisomers was determined by comparison of the peak heights of the two 13C signals by 13C NMR (Figure 2). As shown in Table 1, the d.r. of 7 (and hence the

• of Cbz-L-phenylalanine (40 mg, 0.13 mmol), HOBt (20 mg, 0.2 mmol), EDC (0.03 mL, 0.2 mmol) and Et3N (0.3 mL) were added to a suspension of 6* (4 mg, 0.03 mmol) in CH2Cl2 (4 mL). The resulting solution was stirred overnight at room temperature and partitioned between water and ethyl acetate. The

Hybrid biofunctional nanostructures as stimuli-responsive catalytic systems

• Gernot U. Marten,
• Thorsten Gelbrich and
• Annette M. Schmidt

Beilstein J. Org. Chem. 2010, 6, 922–931, doi:10.3762/bjoc.6.98

• ) (Aldrich, 98%), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) (ABCR, 98%), N-hydroxy succinimide (NHS, Fluka), iron(III) chloride hexahydrate, iron(II) chloride tetrahydrate (Fluka, 98%), ninhydrin (Riedel-de-Haen), oligo(ethylene glycol) methylether methacrylate (OEGMA, Aldrich, Mn

• active ester functions that may have hydrolyzed during storage, 6 mL of 2.21 μM EDC/NHS solution was added. The binding reaction was carried out for 6 h at ambient temperature on a shaker. The obtained trypsin functionalized particles were separated and washed carefully with water to remove any residues

Synthesis of 5-(6-hydroxy-7H-purine-8-ylthio)- 2-(N-hydroxyformamido)pentanoic acid

• Yanmei Zhang,
• Greg Elliot,
• Adrian Saldanha,
• Igor Tsigelny,
• Dennis Carson and
• Wolf Wrasidlo

Beilstein J. Org. Chem. 2010, 6, 742–747, doi:10.3762/bjoc.6.93

• , was added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC, 475.0 mg, 2.48 mmol) followed by DMAP (302.0 mg, 2.48 mmol). After stirring at 0 °C for 30 min, benzyl alcohol (402.0 mg, 3.72 mmol) was added. The reaction mixture was stirred at 0 °C for 1 h, then warmed to room temperature

Synthesis and enzymatic evaluation of 2- and 4-aminothiazole- based inhibitors of neuronal nitric oxide synthase

• Graham R. Lawton,
• Haitao Ji,
• Pavel Martásek,
• Linda J. Roman and
• Richard B. Silverman

Beilstein J. Org. Chem. 2009, 5, No. 28, doi:10.3762/bjoc.5.28

• (2.5 equiv), DMAP, THF, rt, 16 h; viii) TBAF, THF, rt 16 h; ix) PPh3, DIAD, phthalimide, THF, rt, 16 h; x) H2NNH2 (aq), MeOH, rt, 16 h, then 2N HCl, rt, 30 min. Synthesis of compound 3. i) 4-chlorobenzylchloride, EtOH, reflux, 4 h; ii) Boc2O, TEA, MeOH, 3 h; iii) 1 N NaOH, MeOH, rt, 4 h; iv) EDC, HOBt

Synthesis of rigidified flavin–guanidinium ion conjugates and investigation of their photocatalytic properties

• Harald Schmaderer,
• Mouchumi Bhuyan and
• Burkhard König

Beilstein J. Org. Chem. 2009, 5, No. 26, doi:10.3762/bjoc.5.26

• -dihydrobenzo[g]pteridin-10(2H)-yl]ethyl}-3-azabicyclo[3.3.1]nonane-7-carboxamide; Flavin-Boc-guanidin 7 To a solution of HOBt·H2O (89 mg, 580 μmol), EDC (90 mg, 580 μmol) and DIPEA (171 μL, 970 μmol) in CH2Cl2 (6.5 mL) were added compound 6 (252 mg, 480 μmol) and mono Boc-protected guanidine (86 mg, 530 μmol

• -7-carboxamide; Flavin-Boc-guanidin 10 To a solution of HOBt·H2O (226 mg, 1.67 mmol), EDC (226 mg, 1.45 mmol) and DIPEA (498 μL, 970 μmol) in CHCl3 (10 mL) was added compound 9 (548 mg, 969 μmol) and mono Boc-protected guanidine (231 mg, 1.45 mmol) at 0 °C. The mixture was stirred at room temperature

• ). Structure of compound 1 in the solid state. Calculated lowest energy conformation of 1 in the gas phase (AM1, Spartan program package). Flavin–guanidinium ion conjugates 1 and 2 and tetraacetyl riboflavin (3). Synthesis of flavins 1 and 2. Conditions: (i) DMAP, H2O, Δ, 20 h, 71–78%, (ii) HOBt, EDC, NEt(iPr