Binding of tryptophan and tryptophan-containing peptides in water by a glucose naphtho crown ether

• Gianpaolo Gallo and
• Bartosz Lewandowski

Beilstein J. Org. Chem. 2025, 21, 541–546, doi:10.3762/bjoc.21.42

• as well indicated by the lower binding affinity of 1 to the acetylated analogues of peptides 2 and 3. In the case of peptide 4, acetylation of its N-terminus did not affect the stability of the complex with receptor 1. This suggests that 1 interacts with the N-terminal ammonium in 4 to a much lesser

Synthesis of the aggregation pheromone of Tribolium castaneum

• Biyu An,
• Xueyang Wang,
• Ao Jiao,
• Qinghua Bian and
• Jiangchun Zhong

Beilstein J. Org. Chem. 2025, 21, 510–514, doi:10.3762/bjoc.21.38

• (R)-citronellic acid [18], methyl (S)-3-hydroxy-2-methylpropanoate, (S)-2-methyl-1-butanol [19], (R)-2,3-O-isopropylideneglyceraldehyde [20], (R)- and (S)-citronellol [21], (R)-4-methyl-δ-valerolactone [22], porcine pancreatic lipase (PPL)-catalyzed acetylation of racemic citronellol [23], and Evan′s

Synthesis of acenaphthylene-fused heteroarenes and polyoxygenated benzo[j]fluoranthenes via a Pd-catalyzed Suzuki–Miyaura/C–H arylation cascade

• Merve Yence,
• Dilgam Ahmadli,
• Damla Surmeli,
• Umut Mert Karacaoğlu,
• Sujit Pal and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2024, 20, 3290–3298, doi:10.3762/bjoc.20.273

• synthesis of benzo[j]fluoranthene 23 in six steps (Scheme 3). In this sequence, 1,8-DHN (19) was first converted to 1-acetoxy-8-methoxynaphthalene (24) via a selective mono-methylation of 19 followed by acetylation by acetyl chloride in 88% yield over two steps. The more electron-rich ring of naphthalene 24

Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• cycloadducts 29e and 31e in good yields (Scheme 12). Further derivatizations were also carried out: The treatment of 29e with SOCl2 led to interesting unsaturated derivative 32 in a 54% yield. The acetylation of 31e provided 33 in 76% yield. Next, an alkene metathesis of 33 with styrene led to product 34 in 72

Multicomponent reactions driving the discovery and optimization of agents targeting central nervous system pathologies

• Lucía Campos-Prieto,
• Aitor García-Rey,
• Eddy Sotelo and
• Ana Mallo-Abreu

Beilstein J. Org. Chem. 2024, 20, 3151–3173, doi:10.3762/bjoc.20.261

• ] developed artificial, ‘natural-like’ polyphenols, using the Ugi reaction, since it leads to mixed polyphenol–peptidomimetic structures (Scheme 4). The procedure involved an Ugi reaction using phenolic building blocks protected as allyl ethers, followed by deprotection, acetylation, and high-yielding

Cyclodextrin-based rotaxanes for polymer materials: challenge on simultaneous realization of inexpensive production and defined structures

• Yosuke Akae

Beilstein J. Org. Chem. 2024, 20, 3026–3049, doi:10.3762/bjoc.20.252

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• precursors. The base-mediated reaction of 5-chloroanthranilic acid (8a) with chloroacetic acid afforded 8b (Scheme 5) [20]. Acetylation and base-mediated cyclization gave indoxyl 9a which was transformed to indigo 1c by oxidative dimerization. Benzylation finally afforded 1d. 4,6-Benzylidenation of ᴅ

• -glycoside 11a (Scheme 7) [20]. Debenzylation gave product 11b which was transformed to akashin A (11c) by reduction of the azide to the amine in the presence of propane-1,3-dithiol and subsequent debenzoylation. Akashin A was transformed to akashins B and C by acetylation and reaction with diacetyl

• [8][9][10][11]. Therefore, we studied the synthesis of oximes of indirubin-N-glycosides. The reaction of isatin-N-rhamnoside β-16a with 3-acetoxyindole and subsequent acetylation afforded indirubin-N-rhamnoside β-17e which was subsequently deprotected to give oxime β-17f (Scheme 15) [23]. In

Synthesis of tricarbonylated propargylamine and conversion to 2,5-disubstituted oxazole-4-carboxylates

• Kento Iwai,
• Akari Hikasa,
• Kotaro Yoshioka,
• Shinki Tani,
• Kazuto Umezu and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2024, 20, 2827–2833, doi:10.3762/bjoc.20.238

• anhydride, the intermediately formed hemiacetal underwent acetylation, leading to N,O-acetals 1. In this method, an acid amide can be used as an amine masked with an acyl group. Subsequent elimination of acetic acid occurred to afford 2 in situ upon treatment with a base, enabling nucleophilic addition with

Novel truxene-based dipyrromethanes (DPMs): synthesis, spectroscopic characterization and photophysical properties

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2024, 20, 2163–2170, doi:10.3762/bjoc.20.186

• was perfectly matched with the previously reported one [38]. General procedure for acetylation of truxene 10: Compound 10 was dissolved in DCM (15 mL). This solution was gradually added to a AlCl3/acetyl chloride solution at 0 °C, which was prepared by dissolving AlCl3 in acetyl chloride (11) with

Computational toolbox for the analysis of protein–glycan interactions

• Ferran Nieto-Fabregat,
• Maria Pia Lenza,
• Angela Marseglia,
• Cristina Di Carluccio,
• Antonio Molinaro,
• Alba Silipo and
• Roberta Marchetti

Beilstein J. Org. Chem. 2024, 20, 2084–2107, doi:10.3762/bjoc.20.180

• able to add branching points and some sugar derivatisation, including methylation and acetylation. The user has also the possibility to choose the ring type and the anomeric configuration of each monosaccharide. Once the structure is complete, it is possible to download not only the generated .pdb

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• induce a more bioactive compound, fluorine atoms were introduced by acetylation and benzoylation of -NH at 152. Spiro compounds 152–154 were easily afforded in 34–62% overall yields (Scheme 40). The compounds showed excellent coenzymatic effects towards cellobiase activity produced by Chaetomium

Chemo-enzymatic total synthesis: current approaches toward the integration of chemical and enzymatic transformations

• Ryo Tanifuji and
• Hiroki Oguri

Beilstein J. Org. Chem. 2024, 20, 1693–1712, doi:10.3762/bjoc.20.151

• Suzuki–Miyaura coupling with boronic ester 53 and O-acetylation furnished 54. The dienophile component, morachalcone A (44), was synthesized from phenol 55 in four steps including O-prenylation and subsequent Claisen rearrangement, aldol condensation with 56, and deprotection. The key chemo-enzymatic

Primary amine-catalyzed enantioselective 1,4-Michael addition reaction of pyrazolin-5-ones to α,β-unsaturated ketones

• Pooja Goyal,
• Akhil K. Dubey,
• Raghunath Chowdhury and
• Amey Wadawale

Beilstein J. Org. Chem. 2024, 20, 1518–1526, doi:10.3762/bjoc.20.136

• acetylation of the ent-3ba' using acetic anhydride and DABCO, furnishes the desired product ent-3ba. Conclusion In summary, we have realized the Michael addition reaction of 4-unsubstituted pyrazolin-5-ones to α,β-unsaturated ketones under organocatalytic conditions. The developed protocol was efficiently

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• increase was observed upon closing due to the spatial proximity in the cavity between the two substrates. In contrast, the open tweezers showed a higher rate for the acetylation of meta and para substrates as a result of substrate inhibition of the closed cavity. These tweezers constitute a remarkable

Optimizations of lipid II synthesis: an essential glycolipid precursor in bacterial cell wall synthesis and a validated antibiotic target

• Milandip Karak,
• Cian R. Cloonan,
• Brad R. Baker,
• Rachel V. K. Cochrane and
• Stephen A. Cochrane

Beilstein J. Org. Chem. 2024, 20, 220–227, doi:10.3762/bjoc.20.22

• , followed by in situ re-acetylation of the C2-amino group and C6-alcohol with acetic anhydride, resulting in the formation of disaccharide 4 in a one-pot fashion. The anomeric benzyl protecting group in disaccharide 4 was then removed via a Pd/C-catalyzed hydrogenation reaction, producing a mixture of α/β

Synthesis of the 3’-O-sulfated TF antigen with a TEG-N₃ linker for glycodendrimersomes preparation to study lectin binding

• Mark Reihill,
• Hanyue Ma,
• Dennis Bengtsson and
• Stefan Oscarson

Beilstein J. Org. Chem. 2024, 20, 173–180, doi:10.3762/bjoc.20.17

• , led to isolation of a mixture of 2 and a tin-related impurity (n-butyl chain evident by NMR). Acetylation of this material followed by flash chromatography proved ineffective in removing the unwanted entity. To overcome this problem, flash chromatography was performed before stirring with the ion

• following acetylation without purification of the intermediate, why the synthesis is high-yielding (20% overall yield) and easily scalable (9 g of protected disaccharide 7 and 1 gram of target 2 were synthesized). Experimental General methods All reactions containing air- and moisture-sensitive reagents

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• derivative 2.6. The treatment of 2.6 with trimethylamine produced an ammonium salt. A treatment with silver carbonate was applied to remove any traces of bromide salts. Then, the secondary alcohol was deprotected by hydrogenolysis to produce 2.7 (lyso-PAF). Finally, the acetylation of the secondary alcohol

• oxidation with Br2 and hydrolysis, the bromoethyl phosphate 5.4. Finally, the quaternarization with trimethylamine produced 5.5 and the acetylation produced 5.6 PAF. The intermediate compounds like 6.2 (1-O-alkylglycerol) or the protected secondary alcohol 6.6, either as enantiopure or racemic forms, are

• the incorporation of the trityl group, which is reported with 42% yield. The next steps correspond to the adaptation of previously reported methods with the use of bromoethyl dichlorophosphate (10.5) as precursor of the phosphocholine polar head group. The last steps (debenzylation and acetylation

Two new lanostanoid glycosides isolated from a Kenyan polypore Fomitopsis carnea

• Winnie Chemutai Sum,
• Sherif S. Ebada,
• Didsanutda Gonkhom,
• Cony Decock,
• Rémy Bertrand Teponno,
• Josphat Clement Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2023, 19, 1161–1169, doi:10.3762/bjoc.19.84

• effects of compound 1 and related analogues could be realized by C-3 hydrolysis. In 2010, Liu et al. also demonstrated the major role played by changes at C-16 on antibacterial effects of F. pinicola steroids [33]. The acetylation at C-16 reduced the potency compared to the corresponding congener with a

Photocatalytic sequential C–H functionalization expediting acetoxymalonylation of imidazo heterocycles

• Deepak Singh,
• Shyamal Pramanik and
• Soumitra Maity

Beilstein J. Org. Chem. 2023, 19, 666–673, doi:10.3762/bjoc.19.48

• ), light (entry 15) or acetylation agent (entry 16) failed to provide the desired product 4a, displaying the necessity of each component for developing the reaction. Substrate scope With suitable reaction conditions (Table 1, entry 12), we systematically investigated the scope of this acetoxymalonylation

• isolated, further confirming the involvement of a malonyl radical generated by the cleavage of the C–Br bond of 2a [28]. Next, an attempt was made to identify the key intermediate of the reaction (Scheme 3B). When compound 5 was subjected to the acetylation reaction individually with Zn(OAc)2 and AcOH

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

• Jorge de Lima Neto and
• Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

• combretastatin D-1 (1) in 23% overall yield after 16 steps. Later, the same authors performed the enantioselective synthesis of 1 in an attempt to review its absolute configuration [41]. Thus, acetylation of compound 2 followed by the use of Jacobsen’s catalyst [42] to perform the epoxidation of the double bond

Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• -workers [19], through a sequence of reduction to the alcohol, acetylation and reduction with lithium in ammonia (Scheme 3A) [20], and its structure was unambiguously assigned by X-ray crystallography of a silver nitrate adduct [21]. From natural sources, the compound was first obtained from Humulus

Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry

• Eric Gayon,
• Guillaume Lefèvre,
• Olivier Guerret,
• Adrien Tintar and
• Pablo Chourreu

Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15

• . (7E,9Z)-Dodeca-7,9-dien-1-yl acetate (3), the sex pheromone of European grapevine moth (Lobesia botrana), was thus obtained at a 14 g scale, with an overall 85% yield for the one-pot sequence involving the iron-catalyzed cross coupling followed by acetylation with Ac2O (Scheme 4b) [21]. Illustrating

Inline purification in continuous flow synthesis – opportunities and challenges

• Jorge García-Lacuna and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 1720–1740, doi:10.3762/bjoc.18.182

• only. This is facilitated when using heterogeneous catalysts or immobilized enzymes that are retained in cartridge reactors. For instance, Paradisi and co-workers reported an N-acetylation approach to produce melatonin analogs, where the pure product is obtained in the organic phase after evaporation

Total synthesis of grayanane natural products

• Nicolas Fay,
• Rémi Blieck,
• Cyrille Kouklovsky and
• Aurélien de la Torre

Beilstein J. Org. Chem. 2022, 18, 1707–1719, doi:10.3762/bjoc.18.181

• suitable starting material for the SmI2-promoted pinacol coupling, directed by the free hydroxy group, affording a complete selectivity in the formation of the 7-membered ring B. The synthesis of grayanotoxin III was then achieved by acetylation of the secondary alcohols, oxidative cleavage of the MOM

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

• Konstantin Lebedinskiy,
• Volodymyr Lobaz and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170

• as the price of some reagents and relatively low yields. In this work, we describe a method using low-cost reactants, such as methyl tosylate and DIPEA, which provides moderate to high yields and is a reasonable alternative to the existing methods. The acetylation of compound 1 using standard