Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata

• Li-Si Huang,
• Fei He,
• Hui Huang,
• Xiao-Yong Zhang and
• Shu-Hua Qi

Beilstein J. Org. Chem. 2012, 8, 170–176, doi:10.3762/bjoc.8.18

• were very similar to those of compounds 3–5 [5][6]. Compound 3 is a symmetric urea derivative that was formed from the amidation of two molecules of 4 [6]. Comparison of the NMR data of 1 with 3–5 suggested that 1 was an asymmetric urea derivative that was formed from the amidation of 4 and 5 [5][6

• = 8.0 Hz, 1H). The 1H and 13C NMR spectral data of 2 show similarities to those of 3 [5] (Table 1). Comparison of the NMR data of 2 and 3 suggests that 2 is an asymmetric urea derivative that was formed from the amidation of two molecules of 4 [5][6], and the only difference between 2 and 3 is the

• amidation position of the two molecules of 4. Based on the 1H NMR, 13C NMR HSQC, HMBC and 1H–1H COSY spectral data analysis, the structure of 2 was elucidated to be as shown above and named as obtucarbamate D. Urea derivatives are closely related in structure to carbamates. Urea is synthesized in the body

Hyperbranched polyethylenimine bearing cyclodextrin moieties showing temperature and pH controlled dye release

• Indra Böhm,
• Susanne Katharina Kreth and
• Helmut Ritter

Beilstein J. Org. Chem. 2011, 7, 1130–1134, doi:10.3762/bjoc.7.130

• , Scheme S1). Briefly, compound 3 can be obtained through polymer-analogous amidation with 5-hexynoic acid and subsequent reaction with mono-(6-azido-6-desoxy)-β-cyclodextrin by click reaction under microwave assisted conditions. Synthesis of 1,4-di-N-adamantylaminoanthraquinone (2): 2 was synthesized

A novel high-yield synthesis of aminoacyl p-nitroanilines and aminoacyl 7-amino-4-methylcoumarins: Important synthons for the synthesis of chromogenic/fluorogenic protease substrates

• Xinghua Wu,
• Yu Chen,
• Herve Aloysius and
• Longqin Hu

Beilstein J. Org. Chem. 2011, 7, 1030–1035, doi:10.3762/bjoc.7.117

• amino acids or their corresponding commercially available N-hydroxysuccinimide esters. The method involved the in situ formation of selenocarboxylate intermediate of protected amino acids and the subsequent non-nucleophilic amidation with an azide. Common protecting groups used in amino acid/peptide

• -amino-4-methylcoumarin; p-nitroaniline; proteolytic substrate; selenocarboxylate/azide amidation; synthon; Introduction Chromogenic and fluorogenic amino acid/peptide conjugates are widely used as substrates in enzyme assays for protease activity and specificity [1]. Proteolytic cleavage of the amino

• solvent to suppress the potential removal of the Boc protecting group of amino acids. To increase nucleophilicity of the aromatic amino group and hence improve the acylation yield, p-(Boc-amino)aniline was used in place of p-nitroaniline as the starting material for amidation, followed by selective

Chiral gold(I) vs chiral silver complexes as catalysts for the enantioselective synthesis of the second generation GSK-hepatitis C virus inhibitor

• María Martín-Rodríguez,
• Carmen Nájera,
• José M. Sansano,
• Abel de Cózar and
• Fernando P. Cossío

Beilstein J. Org. Chem. 2011, 7, 988–996, doi:10.3762/bjoc.7.111

• )-13/AgClO4 complex is also valuable. With the most enantiomerically enriched cycloadduct 5b, the synthesis of the antiviral agent 2a could be accomplished in two conventional steps involving an amidation reaction and a double ester hydrolysis. The latter step consisted of a first stage TFA-mediated

Application of the diastereoselective photodeconjugation of α,β-unsaturated esters to the synthesis of gymnastatin H

• Ludovic Raffier and
• Olivier Piva

Beilstein J. Org. Chem. 2011, 7, 151–155, doi:10.3762/bjoc.7.21

• ) configuration at the C-6 carbon. By saponification under mild conditions, 24 was converted into carboxylic acid 25 which was implicated into a free-epimerising amidation procedure with HOBt [22] and the readily available O-protected tyrosine derivative 26. Finally, the TBS group of the amino ester moiety was

A new and facile synthetic approach to substituted 2-thioxoquinazolin-4-ones by the annulation of a pyrimidine derivative

• Nimalini D. Moirangthem and
• Warjeet S. Laitonjam

Beilstein J. Org. Chem. 2010, 6, 1056–1060, doi:10.3762/bjoc.6.120

• common synthetic route involves the amidation of 2-aminobenzoic acid or its derivatives, i.e., 2-aminobenzonitrile, 2-aminobenzoates, and 2-arylnitrilium salts, followed by oxidative ring closure [10][11][12][13]. Other synthetic pathways include the cyclization of anthranilamides with aldehydes [14

N-acylation of ethanolamine using lipase: a chemoselective catalyst

• Mazaahir Kidwai,
• Roona Poddar and
• Poonam Mothsra

Beilstein J. Org. Chem. 2009, 5, No. 10, doi:10.3762/bjoc.5.10

• (triacyl glycerol hydrolases EC 3.1.1.3) catalyze hydrolysis, esterification, transesterification, thioesterification, amidation, epoxidation etc. [5][6][7][8][9][10]. The use of immobilized lipases is on the rise, as these work well with non-aqueous media [11]. Apart from the convenient handling, these