Synthesis of the reported structure of piperazirum using a nitro-Mannich reaction as the key stereochemical determining step

• James C. Anderson,
• Andreas S. Kalogirou,
• Michael J. Porter and
• Graham J. Tizzard

Beilstein J. Org. Chem. 2013, 9, 1737–1744, doi:10.3762/bjoc.9.200

• cyclohexanecarbaldehyde [44]. In cases where trifluoroacetylation fails, it is quite common to purify the β-nitroamine by rapid column chromatography, quickly followed by reduction to give the corresponding 1,2-diamine. In this case rapid purification of 15 followed by reduction with Zn/HCl gave the 1,2-diamine 17 as a

Amyloid-β probes: Review of structure–activity and brain-kinetics relationships

• Todd J. Eckroat,
• Abdelrahman S. Mayhoub and
• Sylvie Garneau-Tsodikova

Beilstein J. Org. Chem. 2013, 9, 1012–1044, doi:10.3762/bjoc.9.116

• -bromobenzene-1,2-diamine (147) and p-dimethylaminobenzaldehyde (23) to give 148 followed by installation of the radiolabel (Scheme 11) [97]. Compound 146 showed good binding affinity for Aβ1-42 aggregates (Ki = 9.8 nM), as well as high uptake and rapid clearance in normal mice (4.14% ID/g at 2 min and 0.15% ID

Synthesis and physicochemical characterization of novel phenotypic probes targeting the nuclear factor-kappa B signaling pathway

• Paul M. Hershberger,
• Satyamaheshwar Peddibhotla,
• E. Hampton Sessions,
• Daniela B. Divlianska,
• Ricardo G. Correa,
• Anthony B. Pinkerton,
• John C. Reed and
• Gregory P. Roth

Beilstein J. Org. Chem. 2013, 9, 900–907, doi:10.3762/bjoc.9.103

• ), Raf (57%), and JAK2 (53%)) are relevant to NF-κB pathway regulation. To prepare 4, a synthetic route (Scheme 1) was optimized in a manner that allowed for the preparation of related analogues [9]. The intermediate 1 was prepared through condensation of 4,5-dimethylbenzene-1,2-diamine with potassium

A one-pot catalyst-free synthesis of functionalized pyrrolo[1,2-a]quinoxaline derivatives from benzene-1,2-diamine, acetylenedicarboxylates and ethyl bromopyruvate

• Mohammad Piltan,
• Loghman Moradi,
• Golaleh Abasi and
• Seyed Amir Zarei

Beilstein J. Org. Chem. 2013, 9, 510–515, doi:10.3762/bjoc.9.55

• -diaminobenzene, dialkyl acetylenedicarboxylates, and ethyl bromopyruvate forms pyrrolo[1,2-a]quinoxaline derivatives in good yields. Ethylenediamine also reacts under similar conditions to produce new pyrrolo[1,2-a]pyrazine derivatives. Keywords: acetylenedicarboxylates; benzene-1,2-diamine; ethyl bromopyruvate

• ). The 1H NMR and 13C NMR spectra of products 4b–h were similar to those of 4a, except for the ester moieties, which exhibited characteristic resonances in the appropriate regions of the spectrum. Substitution on the benzene-1,2-diamine was also found to be important. A methyl group provided good yields

• bromopyruvate under similar conditions to form pyrrolo[1,2-a]pyrazine derivatives (Scheme 2). Compounds 9a,b were fully characterized according to their elemental analyses and their IR, 1H NMR and 13C NMR spectra and MS. Conclusion In summary, the reaction between benzene-1,2-diamine and dialkyl

Inter- and intramolecular enantioselective carbolithiation reactions

• Asier Gómez-SanJuan,
• Nuria Sotomayor and
• Esther Lete

Beilstein J. Org. Chem. 2013, 9, 313–322, doi:10.3762/bjoc.9.36

• the lithium atom leads to lower yields and the opposite enantiomer (S)-3-methylindoline (S)-46 with low enantiomeric excess (22% ee) when (−)-sparteine (L1) is used (Scheme 16b). However, in this case, the (1R,2R)-N,N,N’,N’-tetramethylcyclohexane-1,2-diamine (L4) proves to be a more efficient ligand

Metal-mediated aminocatalysis provides mild conditions: Enantioselective Michael addition mediated by primary amino catalysts and alkali-metal ions

• Matthias Leven,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2013, 9, 155–165, doi:10.3762/bjoc.9.18

• vitamin K antagonist, and the dissimilar activity of the enantiomers is well documented in the literature [30][31][32]. The organocatalytic synthesis of warfarin has already been tested with several organocatalysts. Diphenylglycinol derivatives and derivatives of 1,2-diphenylethane-1,2-diamine provided

• of appropriate solvents. Bromine derivative 6, which is based on 1,2-diaminocyclohexane as well, exhibits a markedly higher solubility in THF and can also be dissolved in mixtures of alcohols and DCM. Precatalysts 7 and 8 are derived from 1,2-diphenylethane-1,2-diamine and the solubility of these

• liquids. Nevertheless, the ee could be improved up to 83% (Table 2, entry 7). The results shown in Table 2 indicate that the catalysts 7 and 8 based on 1,2-diphenylethane-1,2-diamine perform indeed better than 5 and 6, based on trans-1,2-diaminocyclohexane: The highest ee that could be obtained by 8 is 83

Organocatalytic C–H activation reactions

• Subhas Chandra Pan

Beilstein J. Org. Chem. 2012, 8, 1374–1384, doi:10.3762/bjoc.8.159

• , potassium tert-butoxide (1.0 equiv) and DMEDA (N,N’-dimethylethane-1,2-diamine) were found to be the best base and catalyst, respectively, providing the desired product 20 in 84% yield (Scheme 14). It is remarkable that cis-cyclohexane-1,2-diol is also a good catalyst for this reaction (81% yield). Under

Derivatives of phenyl tribromomethyl sulfone as novel compounds with potential pesticidal activity

• Krzysztof M. Borys,
• Maciej D. Korzyński and
• Zbigniew Ochal

Beilstein J. Org. Chem. 2012, 8, 259–265, doi:10.3762/bjoc.8.27

• reducing agent. However, this method proceeded solely to debromination, and 4-dibromomethylsulfonyl-1,2-diamine (10) was isolated exclusively. Bromine cleavage in phenyl tribromomethyl sulfones was previously observed also by Fields and Shechter [13], who investigated the addition of phenyl tribromomethyl

Gold-catalyzed oxidation of arylallenes: Synthesis of quinoxalines and benzimidazoles

• Dong-Mei Cui,
• Dan-Wen Zhuang,
• Ying Chen and
• Chen Zhang

Beilstein J. Org. Chem. 2011, 7, 860–865, doi:10.3762/bjoc.7.98

• to form α-diketones and aldehydes in good yields is presented. Further directed synthesis of quinoxalines and benzimidazoles, via the condensation of the resulting α-diketones and aldehydes with benzene-1,2-diamine, was achieved in high yields. Keywords: allene; benzimidazole; gold-catalysis

• /hydration and oxidative cleavage of allenes to form α-diketones and aldehydes, and the synthesis of quinoxalines and benzimidazoles via the condensation of the resulting α-diketones and aldehydes with benzene-1,2-diamine [45][46][47][48][49][50][51][52][53][54][55][56]. Results and Discussion Our initial

• of quinoxalines and benzimidazoles via the condensation of the resulting α-diketones and aldehydes with benzene-1,2-diamine was achieved in high yields. This reaction appears to proceed via oxidation/hydration and oxidative cleavage of the allene, and investigations into the mechanism of this

An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals

• Marcus Baumann,
• Ian R. Baxendale,
• Steven V. Ley and
• Nikzad Nikbin

Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57

• ). An attractive alternative synthesis of sunitinib introduces the amide side chain earlier by ring opening of 4-methyleneoxetan-2-one (43) with N,N-diethylethane-1,2-diamine (44) [10]. The resulting β-keto amide 45 is then converted to the analogous pyrrole by condensation with the previously mentioned

Achiral bis-imine in combination with CoCl₂: A remarkable effect on enantioselectivity of lipase-mediated acetylation of racemic secondary alcohol

• K. Arunkumar,
• M. Appi Reddy,
• T. Sravan Kumar,
• B. Vijaya Kumar,
• K. B. Chandrasekhar,
• P. Rajender Kumar and
• Manojit Pal

Beilstein J. Org. Chem. 2010, 6, 1174–1179, doi:10.3762/bjoc.6.134

• carbonyl compound [20][21][22][23][24], in our hands the reaction of 1,2-amines with aromatic aldehydes under these reaction conditions provided a mixture of mono and bis-Schiff bases. We therefore developed a new and efficient method for the preparation of bis-imines 3 by reacting ethane-1,2-diamine (1

Redox-active tetrathiafulvalene and dithiolene compounds derived from allylic 1,4-diol rearrangement products of disubstituted 1,3-dithiole derivatives

• Filipe Vilela,
• Peter J. Skabara,
• Christopher R. Mason,
• Thomas D. J. Westgate,
• Asun Luquin,
• Simon J. Coles and
• Michael B. Hursthouse

Beilstein J. Org. Chem. 2010, 6, 1002–1014, doi:10.3762/bjoc.6.113

• , 109.4, 104.4, 98.9, 56.0, 55.7, 37.1 and 19.5; νmax (KBr)/cm−1 1650, 1610, 1503, 1294, 1208 and 1033. N,N’-Bis{5-[bis(2,4-dimethoxyphenyl)methyl]-2-thioxo-[1,3]dithiole-4-ylmethylene}ethan-1,2-diamine (22) Compound 21 (0.50 g, 1.12 mmol) was dissolved in methanol (50 cm3). Ethylenediamine (0.06 g, 1.12

Molecular recognition of organic ammonium ions in solution using synthetic receptors

• Andreas Späth and
• Burkhard König

Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32

Chiral trimethylsilylated C₂-symmetrical diamines as phosphorous derivatizing agents for the determination of the enantiomeric excess of chiral alcohols by ¹H NMR

• Anne-Sophie Chauvin and
• Alexandre Alexakis

Beilstein J. Org. Chem. 2006, 2, No. 6, doi:10.1186/1860-5397-2-6

• the nitrogen atom or on the backbone. Results and discussion (R,R)-N,N'-Bis-trimethylsilanylmethylcyclohexane-1,2-diamine 1 was synthesised starting from the stable (R,R)-1,2-diammoniumcyclohexane mono-(+)-tartrate salt 4 and chloromethyltrimethylsilane (Scheme 2), according to a described procedure

• [30]. (R,R)-1,2-diphenyl-N,N'-bis-trimethylsilanylmethyl-ethane-1,2-diamine 2 was prepared by the same method, starting from (R,R)-diphenyl-ethane-1,2-diamine 5 (Scheme 2) [31]. N,N'-Dimethyl-1,2-bis-(3-trimethylsilanyl-phenyl)-ethane-1,2-diamine 3 was synthesised by reductive coupling of methyl-(3

• is substituted by a methyl or a methyltrimethylsilyl moiety, despite the latter being a more bulky substituent (9 and 10, or 11 and 12). However, the Δδ value increases by a factor of two in the case of cyclohexane-1,2-diamine derivatives (9 and 10) compared to 1,2-diphenyl-ethane-1,2-diamine