Towards the total synthesis of keramaphidin B

• Pavol Jakubec,
• Alistair J. M. Farley and
• Darren J. Dixon

Beilstein J. Org. Chem. 2016, 12, 1096–1100, doi:10.3762/bjoc.12.104

• turn be synthesised by an aminolysis/oxidation/olefination sequence of the terminal alcohol 6, following traceless nitro group removal. 5-Nitropiperidin-2-one 6 in turn could be accessed by a nitro-Mannich lactamisation cascade reaction between Michael adduct 7, formaldehyde and a suitable primary

• piperidin-2-one 17 in 71% yield. Lactonisation under Lewis acidic conditions afforded spirocyclic malonamate 18 possessing the correct relative stereochemistry for keramaphidin B, in 84% yield. Aminolysis under neat conditions with hex-5-en-1-amine (19) gave the primary alcohol 20 (67% yield), which was

• compromised during a subsequent three-step nitro-Mannich lactamisation cascade, aminolysis and lactonisation sequence. Further manipulation of the pendant functional groups allowed the synthesis of target compound 5 bearing two alkynes and two terminal alkenes for successive RCM reactions to construct the 11

Preparation of a disulfide-linked precipitative soluble support for solution-phase synthesis of trimeric oligodeoxyribonucleotide 3´-(2-chlorophenylphosphate) building blocks

• Amit M. Jabgunde,
• Alejandro Gimenez Molina,
• Pasi Virta and
• Harri Lönnberg

Beilstein J. Org. Chem. 2015, 11, 1553–1560, doi:10.3762/bjoc.11.171

• -[(acetylthiomethyl)]-1H-1,2,3-triazol-1-ylmethyl]phenyl}pentaerythritol (2) as a thick oil. Careful aminolysis of the thioacetates with butylamine in degassed methanol under inert atmosphere followed by immediate reaction of the exposed mercapto groups with 2-(pyridine-2-yldisulfanyl)ethanol gave the desired

Regio- and stereoselective synthesis of new diaminocyclopentanols

• Evgeni A. Larin,
• Valeri S. Kochubei and
• Yuri M. Atroshchenko

Beilstein J. Org. Chem. 2014, 10, 2513–2520, doi:10.3762/bjoc.10.262

• aminolysis of epoxides 6a,b afforded mainly C1 adducts 13a,b arising from trans-diaxal opening of the epoxide ring. Using a Lewis acid catalyst, epoxides 6a,b were transformed into diaminocyclopentanols 14a,b via an alternative pathway involving the formation of aziridinium intermediate 17. Keywords

• -imidazole (7b). Eventually, Zn(ClO4)2·6H2O and Cs2CO3 were selected as the catalysts for further experiments. These conditions were applied for aminolysis of 3a with N-acetylpiperazine (7c) and 9H-purin-6-amine (7d) (Table 1, entries 13 and 14) to provide 44 and 65% yields of the corresponding

• nucleophilic attack, which gives rise to the formation of products 13a,b with essentially complete regioselectivity (Table 4, entries 1 and 2). Surprisingly, aminolysis of substrates 6a,b under Lewis acid-catalyzed conditions resulted mostly in the formation of regioisomers 14a,b (Table 4, entries 3 and 4

A promising cellulose-based polyzwitterion with pH-sensitive charges

• Thomas Elschner and
• Thomas Heinze

Beilstein J. Org. Chem. 2014, 10, 1549–1556, doi:10.3762/bjoc.10.159

• triethylamine deficiency conditions in order to avoid cross-linking of the polymer chains via carbonate moieties resulting from the strong basicity of the trialkylamine [22]. The aminolysis yields the (3-ethoxy-3-oxopropyl)(N-Boc-2-aminoethyl)cellulose carbamate 4 with a DSβ-alanine ester of 0.88 and a DSBoc

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

• linear fashion starting by amination of acetone cyanohydrin (3.19) followed by CBz-protection of the resulting amine and finally aminolysis of the nitrile 3.20 with hydroxylamine [90] (Scheme 34). The resulting amidoxime 3.21 was then reacted with dimethylacetylene dicarboxylate (DMAD) which upon heating

Some aspects of radical chemistry in the assembly of complex molecular architectures

• Béatrice Quiclet-Sire and
• Samir Z. Zard

Beilstein J. Org. Chem. 2013, 9, 557–576, doi:10.3762/bjoc.9.61

• remaining fluorine to introduce different substituents, as shown by the simple formation of trifluoroethoxy derivative 64. The adducts derived from xanthate 61 can be used in yet another way. Gentle aminolysis of the xanthate frees a thiol, which, under more basic conditions, displaces the ortho-fluorine to

A new synthetic access to 2-N-(glycosyl)thiosemicarbazides from 3-N-(glycosyl)oxadiazolinethiones and the regioselectivity of the glycosylation of their oxadiazolinethione precursors

• El Sayed H. El Ashry,
• El Sayed H. El Tamany,
• Mohy El Din Abdel Fattah,
• Mohamed R. E. Aly,
• Ahmed T. A. Boraei and
• Axel Duerkop

Beilstein J. Org. Chem. 2013, 9, 135–146, doi:10.3762/bjoc.9.16

• purification of mixtures of S- or N-glycosides to obtain the pure N-glycosides. The aminolysis of the respective S- or N-glycosides with ammonia in aqueous methanol served as further confirmation of their structures. While in S-glycosides the glycosyl moiety was cleaved off again, 3-N-(glycosyl

• [32][33] and on 2-N-(glycosyl)thiosemicarbazides II obtained from the aminolysis of 3-N-(glycosyl)oxadiazolinethione precursors, the growing interest in glycosylthiosemicarbazides stimulated the development of direct regioselective formations of the corresponding 3-N-(glycosyl)oxadiazolinethiones

• bond. An intramolecular reaction of the tight ion pair results in migration of the glycosyl moiety from sulfur to nitrogen, which proceeds with complete retention of configuration. As a result, a tight-ion-pair mechanism in which the migrating group retains chirality is suggested (Scheme 2). Aminolysis

Synthesis of a library of tricyclic azepinoisoindolinones

• Bettina Miller,
• Shuli Mao,
• Kara M. George Rosenker,
• Joshua G. Pierce and
• Peter Wipf

Beilstein J. Org. Chem. 2012, 8, 1091–1097, doi:10.3762/bjoc.8.120

• synthesis was achieved by a subsequent alkene epoxidation and zinc-mediated aminolysis reaction. The resulting library products provided selective hits among a large number of high-throughput screens reported in PubChem, thus illustrating the utility of the novel scaffold. Keywords: chemical diversity

• ; epoxide aminolysis; hydrozirconation; isoindolinones; metathesis; N-acyliminium ion; Introduction Isoindolinones represent a common scaffold seen in naturally occurring compounds such as magallanesine [1], lennoxamine [2] and clitocybin A [3], or drug candidates such as pagoclone [4] (Figure 1). These

• steric bulk of the adamantyl group: molecular mechanics calculations indicate that the aminolysis of 5 to regioisomer 10 proceeds with minimal isomerization of the seven-membered ring geometry in the lowest-energy product conformer, whereas the formation of 9 requires a substantial ring flip [41

Coupled chemo(enzymatic) reactions in continuous flow

• Ruslan Yuryev,
• Simon Strompen and
• Andreas Liese

Beilstein J. Org. Chem. 2011, 7, 1449–1467, doi:10.3762/bjoc.7.169

• rac-46 through aminolysis with the excess of the amine 44. The resolution is conducted at 60 °C and yields the corresponding (R)-amide 47 and the remaining essentially enantiopure ester (S)-48 as the products. Due to the advantage provided by entirely omitting the use of solvents, a high space-time

• yield of 1 kg L−1 day−1 was achieved. Apart from the difference in operation temperatures, separation of the two steps of this reaction sequence into individual reactors was also necessary as Novozym 435 is also able to catalyze the unwanted aminolysis of 45. Baxendale et al. [39] established a

Kinetic studies and predictions on the hydrolysis and aminolysis of esters of 2-S-phosphorylacetates

• Milena Trmčić and
• David R. W. Hodgson

Beilstein J. Org. Chem. 2010, 6, 732–741, doi:10.3762/bjoc.6.87

• organic synthesis. Aminolysis of reactive esters in aqueous systems is often used in bioconjugation chemistry, but it must compete against hydrolysis processes. Here we study the kinetics of aminolysis and hydrolysis of 2-S-phosphorylacetate ester intermediates that result from displacement of bromide by

• shortfalls, 2-S-(5′-thiophosphoryluridine)acetic acid esters were prepared using p-nitrophenyl bromoacetate or m-nitrophenyl bromoacetate in combination with uridine-5′-monophosphorothioate. Kinetics of hydrolysis and aminolysis of the resulting p- and m-nitrophenyl 2-S-(5′-thiophosphoryluridine)acetates

• were more reactive with respect to hydrolysis and aminolysis in comparison to their simple acetate progenitors, but their calculated selectivity towards aminolysis vs hydrolysis, while reasonable, would not lead to clean reactions that do not require purification. Extrapolations of the kinetic data

Synthesis of 6-PEtN-α-D-GalpNAc-(1–>6)-β-D-Galp-(1–>4)-β-D-GlcpNAc-(1–>3)-β-D-Galp-(1–>4)-β-D-Glcp, a Haemophilus influenzae lipopolysacharide structure, and biotin and protein conjugates thereof

• Andreas Sundgren,
• Martina Lahmann and
• Stefan Oscarson

Beilstein J. Org. Chem. 2010, 6, 704–708, doi:10.3762/bjoc.6.80

• from 7, Scheme 2). NIS/AgOTf-promoted glycosidation of this acceptor with donor 10 [19] (1.4 equiv) then efficiently gave the β-linked trisaccharide 11 (83%). At this stage the phthalimido group was removed by aminolysis and the resulting amino compound acetylated to yield 12 (93%) with the target

Symmetrical and unsymmetrical α,ω-nucleobase amide-conjugated systems

• Sławomir Boncel,
• Maciej Mączka,
• Krzysztof K. K. Koziol,
• Radosław Motyka and
• Krzysztof Z. Walczak

Beilstein J. Org. Chem. 2010, 6, No. 34, doi:10.3762/bjoc.6.34

• ,ω-nucleobase bolaamphiphiles (VII), capable of forming extraordinary nanotopologies [6]. In order to synthesise a new group of modified, mainly pyrimidinic nucleosides, we employed a simple and effective synthetic pathway based on the catalytic aminolysis of carboxylic acids. Our synthetic approach