1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

• Artem N. Semakin,
• Ivan S. Golovanov,
• Yulia V. Nelyubina and
• Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

• composition studies, A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 119991, Vavilova str. 28, Moscow, Russian Federation 10.3762/bjoc.18.148 Abstract A synthetic route to 1,4,6,10-tetraazaadamantanes (TAADs) bearing free and protected amino groups at the bridge N-atoms

• corresponding linear tris-oximes) and difficulties in the functionalization of N-hydroxy groups [21]. Currently, our research is focusing on TAAD derivatives bearing protected and free amino groups at the bridge nitrogen atoms (N-TAADs, Figure 1c). Our main interest in these products was due to their potential

• as synthetic receptors to form host–guest complexes based on H-bond interactions with amide/carbamoyl groups [31][32]. In addition, N-TAADs can be viewed as analogs of hexahydrazide ligands, which were reported to stabilize high-valent metal complexes [33][34]. Since N-amino groups can be easily

Amamistatins isolated from Nocardia altamirensis

• Till Steinmetz,
• Wolf Hiller and
• Markus Nett

Beilstein J. Org. Chem. 2022, 18, 360–367, doi:10.3762/bjoc.18.40

• the end product of the pathway in N. altamirensis DSM 44997. Previous studies have demonstrated that, in nature, hydroxamates arise from the oxidation of terminal amino groups in amino acid side chains, followed by formylation or acylation of the resulting hydroxylamines. While the oxidations are

Recent developments and trends in the iron- and cobalt-catalyzed Sonogashira reactions

• Surendran Amrutha,
• Sankaran Radhika and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 262–285, doi:10.3762/bjoc.18.31

• (Scheme 21). The product yield was significantly lower only by decreasing the reaction temperature. The amino groups present on the POP backbone enable a suitable electronic surrounding of the cobalt species which promotes the reaction. The catalyst showed excellent recyclability for 8 successive runs

1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

• Ruan Carlos B. Ribeiro,
• Patricia G. Ferreira,
• Amanda de A. Borges,
• Luana da S. M. Forezi,
• Fernando de Carvalho da Silva and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 53–69, doi:10.3762/bjoc.18.5

• used in organic synthesis, they are excellent analytical derivatization reagents to spectrophotometrically determine drugs containing primary and secondary amino groups. This review summarizes the literature involving β-NQS. Keywords: biological activities; derivatization reagents; β-NQS; organic

• drugs containing free primary and secondary amino groups [50][51]. As β-NQS is commercially available, it has become a widely used reagent for the chromogenic determination of pharmaceutical amines by spectrophotometry in pharmaceutical formulations [52]. This method, which uses a reagent to form a

• highlights some important drugs containing primary or secondary amino groups in capsules, tablets, powders, formulations, formulations of associated drugs, injection formulations, and biological fluids [42][58][59][60][61][62][63][64][65][66][67][68][69]. β-NQS reacts with aliphatic and aromatic amines

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

Synthesis of a novel aminobenzene-containing hemicucurbituril and its fluorescence spectral properties with ions

• Qingkai Zeng,
• Qiumeng Long,
• Jihong Lu,
• Li Wang,
• Yuting You,
• Xiaoting Yuan,
• Qianjun Zhang,
• Qingmei Ge,
• Hang Cong and
• Mao Liu

Beilstein J. Org. Chem. 2021, 17, 2840–2847, doi:10.3762/bjoc.17.195

• have been applied as fluorescence and electrochemical chemosensors [38][39][40][41][42][43][44][45]. Herein, we wish to report our endeavor in the facile synthesis of a new hemicucurbituril homologue, aminobenzene-containing hemicucurbituril 4 (Scheme 1). It was assumed that the amino groups could act

Cryogels: recent applications in 3D-bioprinting, injectable cryogels, drug delivery, and wound healing

• Luke O. Jones,
• Leah Williams,
• Tasmin Boam,
• Martin Kalmet,
• Chidubem Oguike and
• Fiona L. Hatton

Beilstein J. Org. Chem. 2021, 17, 2553–2569, doi:10.3762/bjoc.17.171

• -polymerised precursors can cause free radical damage or react with proteins in the human body containing thiols and amino groups [84]. Further toxicity research would be required for all of these cryogels to fully understand how they react in the human body as opposed to animal substitutes. However, the use

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

• were removed with hydrazine under reflux and the free amino groups were acetylated to obtain the fully N-acetylated COS [255]. Control over the pattern of N-acetylation was for the first time achieved using two monosaccharides bearing an azido (N3) and a N-Phth moieties as precursors of the free and N

• could be converted into N-acetates upon reduction with tributyltin hydride and azobisisobutyronitrile (AIBN), and the N-Cbz groups were removed to liberate the free amino groups during hydrogenolysis over Pd/C [259]. A collection of well-defined COS with defined DP and PA was prepared by AGA [93][157

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

• Nikita Brodyagin,
• Martins Katkevics,
• Venubabu Kotikam,
• Christopher A. Ryan and
• Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

Total synthesis of ent-pavettamine

• Memory Zimuwandeyi,
• Manuel A. Fernandes,
• Amanda L. Rousseau and
• Moira L. Bode

Beilstein J. Org. Chem. 2021, 17, 1440–1446, doi:10.3762/bjoc.17.99

• selective functionalization and protection of the primary and secondary hydroxy groups (and later amino groups) was critical for the successful synthesis of the target compound. Unfortunately, each protecting group incorporated increased the synthesis by two non-productive steps; nonetheless our aim to

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Stereoselective synthesis and transformation of pinane-based 2-amino-1,3-diols

• Ákos Bajtel,
• Mounir Raji,
• Matti Haukka,
• Ferenc Fülöp and
• Zsolt Szakonyi

Beilstein J. Org. Chem. 2021, 17, 983–990, doi:10.3762/bjoc.17.80

• , two main synthetic strategies are used to prepare these analogues. One requires the insertion of the alcohol and amino groups in the α,β position with the correct stereochemistry [17][18][19][20]. The second strategy involves a bond formation between two chiral centers to produce the targeted 2-amino

Synthesis and properties of oligonucleotides modified with an N-methylguanidine-bridged nucleic acid (GuNA[Me]) bearing adenine, guanine, or 5-methylcytosine nucleobases

• Naohiro Horie,
• Takao Yamaguchi,
• Shinji Kumagai and
• Satoshi Obika

Beilstein J. Org. Chem. 2021, 17, 622–629, doi:10.3762/bjoc.17.54

• , the 2'-amino groups of 1a–c were converted into guanidine moieties with a methyl group using N-acetyl-S,N'-dimethylisothiourea [28], which yielded 65–83% of the products 2a–c. Subsequently, the designed GuNA[Me] phosphoramidites 3a–c were successfully obtained following the phosphitylation of the 3

Insight into functionalized-macrocycles-guided supramolecular photocatalysis

• Minzan Zuo,
• Krishnasamy Velmurugan,
• Kaiya Wang,
• Xueqi Tian and
• Xiao-Yu Hu

Beilstein J. Org. Chem. 2021, 17, 139–155, doi:10.3762/bjoc.17.15

• cation, forming complexes. Crown ethers also contain a series of derivatives, such as aza-crowns, where the ether oxygen atoms are replaced by amino groups. A well-known tetrazacrown is cyclen. Due to the excellent host–guest properties of crown ethers, they play a very important role in the construction

All-carbon [3 + 2] cycloaddition in natural product synthesis

• Zhuo Wang and
• Junyang Liu

Beilstein J. Org. Chem. 2020, 16, 3015–3031, doi:10.3762/bjoc.16.251

• undoubtedly an efficient synthetic transformation that creates two C–C bonds in a single reaction. However, the prior protection of the reactive functional groups, such as the hydroxy and amino groups, are still necessary for most of the all-carbon [3 + 2] cycloaddition reactions. We predict that further

Easy access to a carbohydrate-based template for stimuli-responsive surfactants

• Thomas Holmstrøm,
• Daniel Raydan and
• Christian Marcus Pedersen

Beilstein J. Org. Chem. 2020, 16, 2788–2794, doi:10.3762/bjoc.16.229

• Caparica, Portugal 10.3762/bjoc.16.229 Abstract In this paper we describe the synthesis of a new carbohydrate-based building block functionalized with azido or amino groups on the 2 and 4 positions. The building block can be synthesized in anomerically pure form in only five scalable steps starting from

• change the conformation of the head group, for example, through a ring flip giving rise to an altered amphiphilicity. Yuasa and co-workers have employed a metal-chelating xylopyranoside derivative as the polar head group [11]. The xylopyranoside was functionalized with two amino groups on the 2- and the

• order to afford an amino functionality on the 2,4-positions thereby giving diamines 9, 10, and 11 (Scheme 2). Having amino groups on these two positions fulfills the requirement of the compound to become a stimuli-responsive surfactant based on the earlier studies by Yuasa and co-workers [11][12

Synthesis of 1,4-benzothiazinones from acylpyruvic acids or furan-2,3-diones and o-aminothiophenol

• Ekaterina E. Stepanova,
• Maksim V. Dmitriev and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2020, 16, 2322–2331, doi:10.3762/bjoc.16.193

• tertiary amines and should only be carefully treated with reagents containing tertiary amino groups. Because of this, we were encouraged to examine EDC as a carbodiimide in the developed procedure (Table 1, entry 30). As expected, we found that the utilization of EDC in this reaction resulted in the

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• Ullmann coupling reaction of 200 to produce the C3-symmetric trinitrotriphenylene 201. Having compound 201 in hand, the nitro groups were further converted into the corresponding amino groups via reduction in the presence of Pd/C under hydrogen gas atmosphere to furnish compound 202 in almost quantitative

Naphthalene diimide bis-guanidinio-carbonyl-pyrrole as a pH-switchable threading DNA intercalator

• Poulami Jana,
• Filip Šupljika,
• Carsten Schmuck and
• Ivo Piantanida

Beilstein J. Org. Chem. 2020, 16, 2201–2211, doi:10.3762/bjoc.16.185

• (pH 7, amino groups close to the NDI unit, green) and two protonated only at weakly acidic conditions (pH 5; acyl guanidinium unit in the GCP moiety, red) positioned at the ends of the pendant arms. Thus, pH control of a number of positive charges can additionally and reversibly control interactions

• adjacent amino groups (pH 7, green) and decorated by two GCP arms protonated at pH 5 (red; pH-switchable DNA groove binders). Synthesis of compound 4. Conditions: a) mono-N-Boc-ethylenediamine, DMF, 90 °C; b) i) trifluoroacetic acid (TFA)/CH2Cl2 1:1, ii) Fmoc-Lys(Boc)-OH, DIPEA, HCTU; c) i) TFA/CH2Cl2 1:1

Naphthalene diimide–amino acid conjugates as novel fluorimetric and CD probes for differentiation between ds-DNA and ds-RNA

• Annike Weißenstein,
• Myroslav O. Vysotsky,
• Ivo Piantanida and
• Frank Würthner

Beilstein J. Org. Chem. 2020, 16, 2032–2045, doi:10.3762/bjoc.16.170

• ]. That would allow in future research combining of the here studied NDI–AA derivatives with the above mentioned and other pH-sensitive fluorophore–AA, to prepare multicolour spectroscopic probes and eventually also FRET pairs. Also, the two NDI–AA conjugates 3a and 3b have protonatable amino groups at

• structure with accessible minor groove at variance to poly(dG-dC)2, which has sterically hindered minor grooves by amino groups, and poly(A)-poly(U) is an A-helix with major groove available for binding of bulky small molecules [38]. The interactions of the NDI derivatives 3a,b, and 5 with DNA/RNA were

Synthesis of six-membered silacycles by borane-catalyzed double sila-Friedel–Crafts reaction

• Yafang Dong,
• Masahiko Sakai,
• Kazuto Fuji,
• Kohei Sekine and
• Yoichiro Kuninobu

Beilstein J. Org. Chem. 2020, 16, 409–414, doi:10.3762/bjoc.16.39

• in good to excellent yields. The optimized reaction conditions were also applicable for diaryl thioethers to afford their corresponding six-membered silacyclic products. The gram-scale synthesis of a representative bis(dimethylamino)phenoxasilin and the transformation of its amino groups have also

• , the transformation of the amino groups in phenoxasilin 3a into phenyl groups was carried out (Scheme 5). First, the ammonium salt 4 was prepared by treating 3a with MeOTf followed by a palladium-catalyzed cross-coupling reaction with the Grignard reagent (PhMgBr) that afforded the desired diphenylated

• halogen substituents or sterical hindrance. A gram-scale synthesis of phenoxasilins and transformation of the amino groups in the phenoxasilin product were also achieved. We hope that the developed protocol will prove to be a useful and efficient method to synthesize six-membered silacyclic compounds

Potent hemithioindigo-based antimitotics photocontrol the microtubule cytoskeleton in cellulo

• Alexander Sailer,
• Franziska Ermer,
• Yvonne Kraus,
• Rebekkah Bingham,
• Ferdinand H. Lutter,
• Julia Ahlfeld and
• Oliver Thorn-Seshold

Beilstein J. Org. Chem. 2020, 16, 125–134, doi:10.3762/bjoc.16.14

• (in ortho-position to the key south ring methoxy group) has been replaced by a synthetically more accessible hydroxy group (delivered via demethylation of a trimethoxy precursor through BBr3). The hydroxy and amino groups have similar size and polarity, and can both act as H-bond donors or acceptors

Synthesis and characterization of bis(4-amino-2-bromo-6-methoxy)azobenzene derivatives

• David Martínez-López,
• Amirhossein Babalhavaeji,
• Diego Sampedro and
• G. Andrew Woolley

Beilstein J. Org. Chem. 2019, 15, 3000–3008, doi:10.3762/bjoc.15.296

• half-life of 6.5 minutes was obtained at room temperature. To enhance the compounds’ water solubility, the morpholino substituents were replaced by piperazino groups because the secondary amino groups on the piperazino units were expected to have pKa values near 10 [22], and so should be protonated at

• least 7 pH units lower than for the tetra-ortho-methoxy compound 1. As noted above, the presence of the piperazino amino groups made compound 5 doubly positively charged at a neutral pH value. This feature was expected to reduce the pKa value of the azonium ion through electrostatic effects [23]. The

SnCl₄-catalyzed solvent-free acetolysis of 2,7-anhydrosialic acid derivatives

• Kesatebrhan Haile Asressu and
• Cheng-Chung Wang

Beilstein J. Org. Chem. 2019, 15, 2990–2999, doi:10.3762/bjoc.15.295

• and acetyl(benzyl)amino derivatives (7 and 9) did not afford the desired acetolysis products. In the course of these reactions, the functional diacetylamino and acetyl(benzyl)amino groups in 7 and 9, respectively, were hydrolyzed to NHAc functionalities, giving 5 and 8, respectively, but with compound

Fluorinated maleimide-substituted porphyrins and chlorins: synthesis and characterization

• Valentina A. Ol’shevskaya,
• Elena G. Kononova and
• Andrei V. Zaitsev

Beilstein J. Org. Chem. 2019, 15, 2704–2709, doi:10.3762/bjoc.15.263

• Zn(II) 3a with SnCl2 in MeOH [38] at ambient temperature smoothly provided the corresponding tetraamino-substituted porphyrin 4a in 91% yield. (Scheme 1). The free amino groups of porphyrin 4a are useful and reactive functionalities for further modifications. It was shown that the interaction of