Self-association of an indole based guanidinium-carboxylate-zwitterion: formation of stable dimers in solution and the solid state

• Carolin Rether,
• Wilhelm Sicking,
• Roland Boese and
• Carsten Schmuck

Beilstein J. Org. Chem. 2010, 6, No. 3, doi:10.3762/bjoc.6.3

• -indole-2-carboxylate 3 was reduced by reaction with hydrogen in the presence of Pd/C to provide the amine 4 in a yield of 98%. For the next stept, first, thiourea was N-Boc-protected at both amino-functions following a literature procedure [20]. Thiourea was deprotonated with sodium hydride and

• (w), 2939 (w), 1668 (s), 1250 (s), 1215(s) cm−1; HR-MS (ESI) calcd for [M+H]+: 205.0972; found 205.0979. N,N’-Di-(tert-butoxycarbonyl)thiourea (5): To a stirred solution of thiourea (570 mg, 7.50 mmol) in dry tetrahydrofuran (150 mL) sodium hydride (1.35 g, 33.80 mmol, 60% in mineral oil) was added

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• selectively mesylated on hydroxyl 2. Treatment with sodium hydride formed the epoxide. The acetate was removed and the epoxide was opened with lithium azide at 150°C. The two resulting alcohols were mesylated and the primary mesylate displaced with benzylamine. The resulting secondary amine was benzylated to

A biphasic oxidation of alcohols to aldehydes and ketones using a simplified packed- bed microreactor

• Andrew Bogdan and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2009, 5, No. 17, doi:10.3762/bjoc.5.17

• catalysts functionalized with an acetylene moiety can be tethered to AO using a Huisgen cycloaddition [39]. Azide-functionalized AO resin (AO-N3, 2) was prepared by treating AO with sodium azide (Scheme 1) [41]. The coupling of 4-hydroxy-TEMPO 3 with propargyl bromide (4) using sodium hydride yielded the

• (2 × 50 mL), Et2O (1 × 25 mL), and dried under vacuum. Elemental analysis afforded a loading of 1.0 mmol N3/g resin. Propargyl ether TEMPO 5 Sodium hydride (150 mg, 6.3 mmol, 1.1 equiv) was added to DMF (10 mL) and stirred at RT. 4-hydroxy-TEMPO (1.02 g, 5.9 mmol, 1.0 equiv) in DMF (10 mL) was added

• drop wise to the sodium hydride suspension at 0 °C and stirred until gas evolution ceased. Propargyl bromide (80% in toluene, 800 μL, 7.4 mmol, 1.3 equiv) in DMF (10 mL) was added at 0 °C and the reaction was allowed to warm up to RT and stirred overnight. The reaction was quenched with water and the

End game strategies towards the total synthesis of vibsanin E, 3-hydroxyvibsanin E, furanovibsanin A, and 3-O-methylfuranovibsanin A

• Brett D. Schwartz,
• Craig M. Williams and
• Paul V. Bernhardt

Beilstein J. Org. Chem. 2008, 4, No. 34, doi:10.3762/bjoc.4.34

• epoxide ring opened product (i.e. 28) was isolated (via epoxide 29). Subsequent treatment of the crude material (i.e. 28) with sodium hydride gave as the sole product the TBS protected α-hydroxy ketone 30 in 80% yield over two steps, via a 1,2-Brook rearrangement. The unprotected derivative 31 could be

Analogues of amphibian alkaloids: total synthesis of (5R,8S,8aS)-(−)-8-methyl- 5-pentyloctahydroindolizine (8-epi-indolizidine 209B) and [(1S,4R,9aS)-(−)-4-pentyloctahydro- 2H-quinolizin- 1-yl]methanol

• Joseph P. Michael,
• Claudia Accone,
• Charles B. de Koning and
• Christiaan W. van der Westhuyzen

Beilstein J. Org. Chem. 2008, 4, No. 5, doi:10.1186/1860-5397-4-5

• lactam (+)-26 was troublesome, giving at best a yield of 52% when performed with sodium hydride and tetrabutylammonium iodide in N,N-dimethylformamide. An effortless thionation of 26 with Lawesson's reagent in boiling toluene produced the thiolactam (+)-27 in 92% yield. Eschenmoser sulfide contraction

Aroylketene dithioacetal chemistry: facile synthesis of 4-aroyl- 3-methylsulfanyl- 2-tosylpyrroles from aroylketene dithioacetals and TosMIC

• H. Surya Prakash Rao and
• S. Sivakumar

Beilstein J. Org. Chem. 2007, 3, No. 31, doi:10.1186/1860-5397-3-31

• H. Surya Prakash Rao S. Sivakumar Department of Chemistry, Pondicherry University, Puducherry, 605 014, India 10.1186/1860-5397-3-31 Abstract The cycloaddition of the von Leusen's reagent (p-tolylsulfonyl)methyl isocyanide (TosMIC) to α-aroylketene dithioacetals (AKDTAs) in the presence of sodium

• hydride in THF at rt resulted in a facile synthesis of the 4-aroyl-3-methylsulfanyl-2-tosylpyrroles 3 in good yield along with a minor amount of 4-[(4-methylphenyl)sulfonyl]-1-[(methylsulfanyl)methyl]-1H-imidazole 4. This study lead to the synthesis of 2,3,4-trisubstiuted pyrroles having 1-naphthoyl/2

Total syntheses of oxygenated brazanquinones via regioselective homologous anionic Fries rearrangement of benzylic O-carbamates

• Glaucia Barbosa Candido Alves Slana,
• Mariângela Soares de Azevedo,
• Rosângela Sabattini Capella Lopes,
• Cláudio Cerqueira Lopes and
• Jari Nobrega Cardoso

Beilstein J. Org. Chem. 2006, 2, No. 1, doi:10.1186/1860-5397-2-1

• -diethylcarbamoyl chloride, and sodium hydride afforded the carbamates 2a-2d (Scheme 2). The carbamates 2a-2c were cyclized in the presence of excess sec-BuLi in THF at -78°C to afford the desired brazanquinones 1a-1c in reasonable yields (54%–57%) (Scheme 2). The mechanism suggested by us and shown in Scheme 1