Regioselective (thio)carbamoylation of 2,7-di-tert-butylpyrene at the 1-position with iso(thio)cyanates

• Anna Wrona-Piotrowicz,
• Marzena Witalewska,
• Janusz Zakrzewski and
• Anna Makal

Beilstein J. Org. Chem. 2017, 13, 1032–1038, doi:10.3762/bjoc.13.102

• has been reported that nitration and bromination of 2 take place at the 1-position (however, the bromine atom in 1-bromopyrene can migrate into the 4-position in the presence of AlCl3) [8][9], whereas Friedel–Crafts acylation and Vilsmeier formylation take place at the 4-position [10]. We recently

• whether TfOH-promoted Friedel–Crafts acylation of 2 will also occur at the 1-position. For this purpose, we examined the reaction of 2 with acetic acid and trifluoroacetic anhydride, (TFAA)/TfOH, according to our protocol used for the acylation of pyrene with alkynoic acids [25]. However, in this case we

• opinion, the observed difference in the regioselectivity of the (thio)carbamoylation and acylation of 2 may be due to different bulkiness of the reacting electrophile: the electrophilic center of the protonated iso(thio)cyanate is relatively unhindered and able to attack the electronically activated but

Automating multistep flow synthesis: approach and challenges in integrating chemistry, machines and logic

• Chinmay A. Shukla and
• Amol A. Kulkarni

Beilstein J. Org. Chem. 2017, 13, 960–987, doi:10.3762/bjoc.13.97

• and one separation step. In the first step, a Friedel–Crafts acylation of isobutylbenzene (1 equiv) and propionyl chloride (1.17 equiv) in the presence of AlCl3 as Lewis acid was carried out in a tubular reactor. The residence time is one minute, and the temperature is maintained at 87 °C. The outlet

First total synthesis of kipukasin A

• Chuang Li,
• Haixin Ding,
• Zhizhong Ruan,
• Yirong Zhou and
• Qiang Xiao

Beilstein J. Org. Chem. 2017, 13, 855–862, doi:10.3762/bjoc.13.86

• Sonogashira cross-coupling with 1-hexyne provided ribose 14 in 78% yield [35]. Subsequently, using DMAP as acylation catalyst and triethylamine as base, the former synthesized 2,4-dimethoxy-6-methylbenzoyl chloride (9) reacted with ribose 14 to 3-O-(2,4-dimethoxy-6-methylbenzoyl)ribose 15 in 74% yield

DMAP-assisted sulfonylation as an efficient step for the methylation of primary amine motifs on solid support

• Johnny N. Naoum,
• Koushik Chandra,
• Dorit Shemesh,
• R. Benny Gerber,
• Chaim Gilon and
• Mattan Hurevich

Beilstein J. Org. Chem. 2017, 13, 806–816, doi:10.3762/bjoc.13.81

• several amine motifs. 4-Dimethylaminopyridine (DMAP) has been reported to assist in the sulfonylation and acylation of weak nucleophiles such as secondary amines, alcohols, amides, and sterically hindered amines when used as catalyst in addition to a base additive [28][29][30][31]. It has been suggested

• effective reagent compared to the other additives used. DMAP is used as a catalyst in acylation reactions as it acts via a nucleophilic addition mechanism [34][37][40]. In nucleophilic catalysed acylation, the mechanism involves a step in which the DMAP replaces the leaving group on the carbonyl group

Derivatives of the triaminoguanidinium ion, 5. Acylation of triaminoguanidines leading to symmetrical tris(acylamino)guanidines and mesoionic 1,2,4-triazolium-3-aminides

• Jan Szabo,
• Julian Greiner and
• Gerhard Maas

Beilstein J. Org. Chem. 2017, 13, 579–588, doi:10.3762/bjoc.13.57

• went on to a 3,6-di(pyrazol-1-yl)-1,2,4,5-tetrazine [11], and with 1,1,1-trifluoro-2,4-pentanedione two branches of TAG-Cl were converted into pyrazoline moieties and the third one into an enaminone [12]. Not much is known about the acylation of triaminoguanidines. Reactions with carboxylic acids have

• -thiadiazolium-2-phenylaminides. We present now the results of our studies on the acylation of triaminoguanidines with carboxylic acid chlorides. Further, we show that N,N’,N’’-tris(benzylamino)guanidine reacts with acid chlorides to afford either the threefold N-acylation product or a mesoionic 1,2,4-triazolium

• ]. Results and Discussion Acylation of triaminoguanidine Triaminoguanidine is highly soluble in water [34], and triaminoguanidinium chloride (TAG-Cl, 1) is soluble in hot water or water/ethanol mixtures, but both are insoluble or sparingly soluble in common organic solvents. Since aqueous media cannot be

Pd- and Cu-catalyzed approaches in the syntheses of new cholane aminoanthraquinone pincer-like ligands

• Nikolay V. Lukashev,
• Gennadii A. Grabovyi,
• Dmitry A. Erzunov,
• Alexey V. Kazantsev,
• Gennadij V. Latyshev,
• Alexei D. Averin and
• Irina P. Beletskaya.

Beilstein J. Org. Chem. 2017, 13, 564–570, doi:10.3762/bjoc.13.55

• serve as sensors for aromatic compounds [24]. During the first decade of the XXI century, the main approaches to cyclic and pincer cholane derivatives were based on “classical” organic transformations (acylation, alkylation, etc.) [7][8][25][26][27]. Later, two modern synthetic approaches based on metal

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• of acylation or alkylation reaction, the intermediate 21a with activated aromatic ring, always led to the 1-indanone formation, in contrast to the acylated intermediate 21b with deactivated aromatic ring (Scheme 8). In the same year, Xu et al. have patented a synthesis of 5-chloro-1-indanone via the

• reaction of malonic acid with chlorobenzaldehyde [21]. In the first step, the substrates reacted in the presence of formic acid and diethylamine to form 3-chlorophenylpropionic acid followed by a intramolecular Friedel–Crafts acylation with malonyl chloride in the presence of zinc chloride to give 5-chloro

• -arylpropanoic and 4-arylbutanoic acids has been reported in 2015 by Le et al. [22]. The authors applied a microwave-assisted intramolecular Friedel–Crafts acylation catalyzed by metal triflate in triflate-anion containing ionic liquids. This synthesis proceeded with the goals of green chemistry and allowed to

Highly reactive, liquid diacrylamides via synergistic combination of spatially arranged curing moieties

• Maximilian Maier,
• Magnus S. Schmidt,
• Markus Ringwald and
• Christoph P. Fik

Beilstein J. Org. Chem. 2017, 13, 372–383, doi:10.3762/bjoc.13.40

• could isolate crude diamines 8 and 9, containing significant amounts (10–15%) of the tertiary amines 8a and 9a (Scheme 3) or diamine 16, respectively; each could be used without further purification. Classical acylation with acetyl chloride or acryloyl chloride in the presence of triethylamine led to

• allyl chloride to 13, we could not observe any exothermic behavior or fast formation of the desired compound. So we decided to raise the temperature to 60 °C for 24 hours resulting in a significant increase of product formation. The subsequent direct acylation of the crude product 11 with acryloyl

Polyketide stereocontrol: a study in chemical biology

• Kira J. Weissman

Beilstein J. Org. Chem. 2017, 13, 348–371, doi:10.3762/bjoc.13.39

• resulting enantiomeric materials, it was then shown by autoradiography that acylation of all six DEBS proteins is highly specific for the (2S)-isomer (7) [26], implying that the six AT domains present in the multienzymes select exclusively this stereoisomer (Figure 5). Subsequent studies in vitro with a

NMR reaction monitoring in flow synthesis

• M. Victoria Gomez and
• Antonio de la Hoz

Beilstein J. Org. Chem. 2017, 13, 285–300, doi:10.3762/bjoc.13.31

• with a line of <1 Hz in ethanol. As a proof-of-concept, the integrated flow system (microreactor-stripline NMR chip) was tested in the acylation of benzyl alcohol with acetyl chloride (Figure 7) using DIPEA as the base. The kinetics were studied by in situ monitoring and it was found that 70

A novel method for heterocyclic amide–thioamide transformations

• Walid Fathalla,
• Ibrahim A. I. Ali and
• Pavel Pazdera

Beilstein J. Org. Chem. 2017, 13, 174–181, doi:10.3762/bjoc.13.20

• heating isatine with malonic acid followed by esterification of the produced quinoline carboxylic acid with methanol in the presence of sulfuric acid at 80 °C for 6 h. 4-Arylphthalazin-1(2H)-ones A7 and A8 [24][25] were prepared by Friedel–Crafts acylation reaction of N-aminophthalimide with either

The digital code driven autonomous synthesis of ibuprofen automated in a 3D-printer-based robot

• Philip J. Kitson,
• Stefan Glatzel and
• Leroy Cronin

Beilstein J. Org. Chem. 2016, 12, 2776–2783, doi:10.3762/bjoc.12.276

• platform is a three-step synthesis of the popular nonsteroidal anti-inflammatory drug ibuprofen ((R,S)-2-(4-(2-methylpropyl)phenyl)propanoic acid) starting from isobutylbenzene and propanoic acid (see Scheme 1). These starting materials undergo a Friedel–Crafts acylation using trifluoromethanesulfonic

• the debug feature of the process control software. For this progression was paused after each stage and aliquots taken from the reaction mixture to be analysed by NMR to ensure the synthesis was proceeding as planned (giving approximate yields by 1H NMR of 71% for the initial acylation step and 64

Symmetry-based approach to oligostilbenoids: Rapid entry to viniferifuran, shoreaphenol, malibatol A, and diptoindonesin G

• Youngeun Jung,
• Dileep Kumar Singh and
• Ikyon Kim

Beilstein J. Org. Chem. 2016, 12, 2689–2693, doi:10.3762/bjoc.12.266

• diptoindonesin G, a potent cytotoxic and immunosuppressant agent [16][17], by using a highly efficient domino cyclodehydration/intramolecular Friedel–Crafts acylation/regioselective demethylation sequence as a key transformation. Very recently, a dual functional role of diptoindonesin G in modulating α and β

Et₃B-mediated and palladium-catalyzed direct allylation of β-dicarbonyl compounds with Morita–Baylis–Hillman alcohols

• Ahlem Abidi,
• Yosra Oueslati and
• Farhat Rezgui

Beilstein J. Org. Chem. 2016, 12, 2402–2409, doi:10.3762/bjoc.12.234

• of the MBH carboxylates with aliphatic 1,3-diketones in the presence of K2CO3. A drawback of these synthetic approaches is the need to first perform the acylation step of the corresponding allyl MBH alcohols. For this reason, we herein report an efficient direct method for the allylation of β

Tunable microwave-assisted method for the solvent-free and catalyst-free peracetylation of natural products

• Manuela Oliverio,
• Paola Costanzo,
• Monica Nardi,
• Carla Calandruccio,
• Raffaele Salerno and
• Antonio Procopio

Beilstein J. Org. Chem. 2016, 12, 2222–2233, doi:10.3762/bjoc.12.214

• several functionalities at room temperature in good to excellent yields, it is worth noting that some of them use metal-based catalysts needing long preparation procedures, or in the case of non-metal-based catalysts, inorganic acids are employed to activate acylation. On the other hand, the increasing

Solvent-free synthesis of novel para-menthane-3,8-diol ester derivatives from citronellal using a polymer-supported scandium triflate catalyst

• Lubabalo Mafu,
• Ben Zeelie and
• Paul Watts

Beilstein J. Org. Chem. 2016, 12, 2046–2054, doi:10.3762/bjoc.12.193

• environmentally friendly method for the synthesis of para-menthane-3,8-diol from natural citronellal oil in 96% yield, under solvent free aqueous conditions. The acylation of para-menthane-3,8-diol with various acid anhydrides over polymer-supported scandium triflate (PS-Sc(OTf)3) catalyst was subsequently

• : acylation; diesters; para-menthane-3,8-diol; PS-Sc(OTf)3; Introduction Although South Africa has a substantial petrochemical industry, the fine chemical industry is very small and most chemicals are imported. As such there is significant interest in the use of natural resources for the manufacture of added

• -known as an active insect repellent and can be found naturally as a minor component of citriodora oil [2]. Considering the chemical structure of 3, two reactive hydroxy groups are present which can undergo an organic transformation, such as acylation, to yield natural bio-based compounds. The acylation

Unusual reactions of diazocarbonyl compounds with α,β-unsaturated δ-amino esters: Rh(II)-catalyzed Wolff rearrangement and oxidative cleavage of N–H-insertion products

• Valerij A. Nikolaev,
• Jury J. Medvedev,
• Olesia S. Galkina,
• Ksenia V. Azarova and
• Christoph Schneider

Beilstein J. Org. Chem. 2016, 12, 1904–1910, doi:10.3762/bjoc.12.180

• as a consequence of the initial Wolff rearrangement of diazoketoesters 3a,b accompanied by acylation of the N–H-group of aminoester 1 with α-oxoketene formed. When passing from diazoketoesters 3a,b to dibenzoyldiazomethane 3с, the formation of N,N-disubstituted 2-oxo-2-phenylacetamide 7 was observed

Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines

• David R. Chisholm,
• Garr-Layy Zhou,
• Ehmke Pohl,
• Roy Valentine and
• Andrew Whiting

Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174

• the inexpensive 3,3-dimethylallyl bromide/chloride, followed by cyclisation mediated by Lewis acids, or under acidic conditions [5][6]. A second, analogous approach involves an initial acylation with the commercially available 3,3-dimethylacryloyl chloride, followed by Friedel–Crafts cyclisations that

• reaction, and a third synthetic route was therefore devised that would employ this methodology. A common approach in the literature towards similar THQs involves an initial acylation of the starting aniline using 3,3-dimethylacryloyl chloride, followed by a high temperature cyclisation employing Lewis

• probe this, commercially available 4-iodo-2-methylaniline (11) was employed as the starting material in order to circumvent the low-yielding iodination step. This starting material is also readily synthesised from o-toluidine (5) using a pyridine–iodine iodination [16]. Initial acylation of 11 with 3,3

One-pot synthesis of 4′-alkyl-4-cyanobiaryls on the basis of the terephthalonitrile dianion and neutral aromatic nitrile cross-coupling

• Roman Yu. Peshkov,
• Elena V. Panteleeva,
• Wang Chunyan,
• Evgeny V. Tretyakov and
• Vitalij D. Shteingarts

Beilstein J. Org. Chem. 2016, 12, 1577–1584, doi:10.3762/bjoc.12.153

• acylation–reduction–halogenation–cyanodehalogenation (Scheme 1) [15], are currently being replaced with methods based on transition-metal-catalyzed biaryl cross-coupling [16][17][18][19][20][21]. This methodology is well developed, compatible with different substituents in the substrate and opens up a new

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• thioester to a hydroxy group (d in Scheme 2). A Michael addition–lactonisation cascade leads to pyranones with a substituent in the 4-position 16 (e in Scheme 2). 3-Acylfuran-2-ones (19, 3-acyltetronates) are formed by acylation–Dieckmann condensation between 2-hydroxythioesters 18 and β-ketothioesters 17

• lactonisation yielding the pyran-2-one attached to the caged ring system [137]. 1.7 Furanones 1.7.1 Acylation–Dieckmann condensation: Tetronates. Tetronates (4-hydroxyfuran-2(5H)-ones, 145a/145b) are an abundant type of heterocycles with a broad spectrum of biological activities (Figure 5) [138][139]. In

• -activating FkbH-like protein, an acyl carrier protein (ACP) that intermediately carries the glycerate unit and a FabH-like protein that condenses the ACP-bound glycerate with an ACP-bound β-ketothioester in an acylation–Dieckmann condensation reaction cascade (Scheme 22) [139]. This scenario has been

Synthesis of ferrocenyl-substituted 1,3-dithiolanes via [3 + 2]-cycloadditions of ferrocenyl hetaryl thioketones with thiocarbonyl S-methanides

• Grzegorz Mlostoń,
• Róża Hamera-Fałdyga,
• Anthony Linden and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2016, 12, 1421–1427, doi:10.3762/bjoc.12.136

• described [1]. The latter substrates were prepared efficiently via acylation of ferrocene with in situ generated mixed anhydrides containing a trifluoroacetyl unit or, alternatively, by ferrocenylation of furan, thiophene or selenophene with mixed trifluoroacetyl anhydride. The obtained ferrocenyl

Application of Cu(I)-catalyzed azide–alkyne cycloaddition for the design and synthesis of sequence specific probes targeting double-stranded DNA

• Svetlana V. Vasilyeva,
• Vyacheslav V. Filichev and
• Alexandre S. Boutorine

Beilstein J. Org. Chem. 2016, 12, 1348–1360, doi:10.3762/bjoc.12.128

• . The linker 4 is designed for functionalization of either commercial amino-modified oligonucleotides or amine-bearing polyamides. It contains an alkyne group for CuAAC and an activated ester for the acylation of amino groups. The linkers 5–7 of different lengths contain an azide group for CuAAC and a

• ) bearing either alkyne or azide groups were obtained via acylation of their N-terminal amine by the activated esters method in DMF in the presence of Hünig's base (see Supporting Information File 1 for experimental details). We have pursued several goals: 1) to synthesize a variety of modified MGBs with

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• . Acylation of the hydroxy group of quinidine resulted in complete loss of enantioselectivity, suggesting that hydrogen-bonding contacts between the catalyst’s hydroxy group and the substrate are important for organizing the transition state. Using catalytic quinine (25) the pseudo-enantiomer of the quinidine

NeoPHOX – a structurally tunable ligand system for asymmetric catalysis

• Jaroslav Padevět,
• Marcus G. Schrems,
• Robin Scheil and
• Andreas Pfaltz

Beilstein J. Org. Chem. 2016, 12, 1185–1195, doi:10.3762/bjoc.12.114

• these conditions, although this method had been successfully used for the alkylation and acylation of the tertiary alcohol function of analogous serine derived PHOX ligands [30]. Among various amines, 2,6-lutidine was finally identified as a suitable base for conversion to the desired derivatives in 67

• is available. The subsequent silylation or acylation of the hydroxy group gives access to a library of diverse NeoPHOX ligands. In this way the steric size and the coordination ability of the substituent at the stereogenic center can be tuned for a specific application. Structural motifs of

Synthesis of highly functionalized 2,2'-bipyridines by cyclocondensation of β-ketoenamides – scope and limitations

• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2016, 12, 1170–1177, doi:10.3762/bjoc.12.112

• corresponding β-ketoenamines 2a–e were converted into different β-ketoenamides 3a–g by N-acylation with 2-pyridinecarboxylic acid derivatives. These β-ketoenamides were treated with a mixture of TMSOTf and Hünig’s base to promote the cyclocondensation to 4-hydroxypyridine derivatives. Their immediate O

• we reported on a new pyridine synthesis starting from symmetrically substituted 1,3-diketones 1a and 1b, respectively, that were converted into the corresponding β-ketoenamines and subsequently by N-acylation into β-ketoenamides such as 3a or 3b [1]. Their cyclocondensation followed by O-alkylation

• to this compound class the design of new derivatives is possible thus supplementing the existing collection of available 2,2´-bipyridines. Results and Discussion First we prepared the corresponding β-ketoenamines 2 required for the N-acylation step (Scheme 2). The known compounds 2a and 2b are