Synthesis and HDAC inhibitory activity of pyrimidine-based hydroxamic acids

• Virginija Jakubkiene,
• Gabrielius Ernis Valiulis,
• Markus Schweipert,
• Asta Zubriene,
• Daumantas Matulis,
• Franz-Josef Meyer-Almes and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 837–844, doi:10.3762/bjoc.18.84

• To a suspension of compound 5 (0.274 g, 1 mmol) in dry DMSO (0.3 mL) the corresponding amine (2 mmol; in the case of 8 – the solution of dimethylamine in DMSO) was added. The reaction mixture was stirred at 50–70 °C for 0.5 h, then cooled to room temperature, and poured into ice water (10 mL). The

• resultant precipitate was collected by filtration, washed with water, dried, and recrystallized from hexane. 6-Methyluracil (10) Method A. To a suspension of compound 5 (0.274 g, 1 mmol) in DMSO (0.3 mL) H2O (0.036 g, 2 mmol) was added. The reaction mixture was stirred at 100 °C for 0.5 h, then cooled to

• Na2SO4, and evaporated under reduced pressure. The residue was purified by column chromatography. FDA-approved HDAC inhibitors with a hydroxamic acid moiety. The conformational and tautomeric forms of hydroxamic acids according to [36]. Fragment of the 1H NMR spectrum in DMSO-d6 of compound 12. Synthesis

Cholyl 1,3,4-oxadiazole hybrid compounds: design, synthesis and antimicrobial assessment

• Anas J. Rasras,
• Mohamed El-Naggar,
• Nesreen A. Safwat and
• Raed A. Al-Qawasmeh

Beilstein J. Org. Chem. 2022, 18, 631–638, doi:10.3762/bjoc.18.63

• of 22 diverse compounds. Briefly, the alkyne 3 was treated with formaldehyde, a secondary amine, and CuI as catalyst in DMSO (Scheme 3). The three components were stirred at room temperature for 3 h to furnish the desired compounds 4a–v in moderate to excellent yields [14][34]. By this route, diverse

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• -bonding, which would lead to catalytic quenching, a unique design strategy was applied. Instead of using a cis-blocked palladium(II) unit for self-assembly, Pd(NO3)2 was employed along with the triazole-based 0° clip 13. In a one-pot reaction, 12 and 13 in DMSO were treated with Pd(NO3)2 in a 1:1:1 ratio

A study of the photochemical behavior of terarylenes containing allomaltol and pyrazole fragments

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2022, 18, 588–596, doi:10.3762/bjoc.18.61

• in a solution of DMSO-d6. UV irradiation at a wavelength of 365 nm for 48 h in an NMR tube did not lead to any transformations of the starting pyrazole 16. Our attempts to carry out the photocyclization of pyrazole 16 in various solvents (DMF, acetonitrile, toluene, ethanol, methylene chloride

• ). The phototransformation of compound 12a was studied using NMR monitoring. UV irradiation was carried out at a wavelength of 365 nm in a solution of DMSO-d6 (Figure 1). It should be noted that after UV irradiation for 8 h of the studied sample the NMR spectrum contained signals of protons of the

• solvents excluding acetic acid, DMSO and DMF. Initially, UV irradiation of compound 12a was carried out at a wavelength of 365 nm in a solution of DMSO in common glassware for 24 h. However, subsequent water treatment did not allow the isolation of the target product 14a. Due to the fact that aqueous

Synthesis of a new water-soluble hexacarboxylated tribenzotriquinacene derivative and its competitive host–guest interaction for drug delivery

• Man-Ping Li,
• Nan Yang and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2022, 18, 539–548, doi:10.3762/bjoc.18.56

• was collected by suction filtration, washed, and dried to obtain compound 2 as a yellow solid (3.76 g, 73%). Mp 104.8–106.6 °C; 1H NMR (400 MHz, DMSO-d6, 25 °C) δ 8.18 (s, 6H), 7.36 (s, 6H), 5.36 (s, 12H), 5.21, 5.17 (ABq, J = 12.4 Hz, 12H), 4.21 (s, 3H), 4.15 (q, J = 7.1 Hz, 12H), 1.58 (s, 3H), 1.19

• (t, J = 7.1 Hz, 18H); 13C NMR (100 MHz, DMSO-d6, 25 °C) δ 167.20, 147.89, 143.15, 137.57, 126.07, 110.42, 62.61, 62.55, 62.15, 61.50, 50.38, 27.48, 13.93; (+)-ESI-HRMS (m/z): [M + H]+ calcd for C65H73N18O18, 1393.5345; found, 1393.5354 (Δ = +0.7 ppm). Synthesis of compound 3. To a methanol solution

• was collected by suction filtration, and washed sequentially with water, dichloromethane, and acetone to give compound 3 as a colorless solid (0.37 g, 85%). Mp 59.6–60.7 °C; 1H NMR (400 MHz, DMSO-d6, 25 °C) δ 8.19 (br s, 6H), 7.38 (br s, 6H), 5.26 (br s, 12H), 5.21 (br s, 12H), 4.23 (s, 3H), 1.60 (s

Synthesis of 3,4,5-trisubstituted isoxazoles in water via a [3 + 2]-cycloaddition of nitrile oxides and 1,3-diketones, β-ketoesters, or β-ketoamides

• Md Imran Hossain,
• Md Imdadul H. Khan,
• Seong Jong Kim and
• Hoang V. Le

Beilstein J. Org. Chem. 2022, 18, 446–458, doi:10.3762/bjoc.18.47

• spectrometer using CDCl3, methanol-d4, or DMSO-d6 as the solvent. Chemical shifts (δ) were recorded in parts per million and referenced to CDCl3 (7.24 ppm for 1H NMR and 77.23 ppm for 13C NMR), methanol-d4 (3.31 ppm for 1H NMR and 49.15 ppm for 13C NMR), or DMSO-d6 (2.50 ppm for 1H NMR and 39.52 ppm for 13C

Cs₂CO₃-Promoted reaction of tertiary bromopropargylic alcohols and phenols in DMF: a novel approach to α-phenoxyketones

• Ol'ga G. Volostnykh,
• Olesya A. Shemyakina,
• Anton V. Stepanov and
• Igor' A. Ushakov

Beilstein J. Org. Chem. 2022, 18, 420–428, doi:10.3762/bjoc.18.44

• triple bond is a minor direction for the reaction of bromopropargylic alcohols and phenol in the presence of Cs2CO3/DMF, which was completely suppressed by addition of water. When DMF was replaced by DMSO (Table 1, entry 13), the preparative yield of reaction products decreased possibly due to product

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• -naphthoquinone (18) were obtained in 80% yield with a 75:25 ratio, respectively (Scheme 2, method A). In the methylation reaction using methyl radicals generated by the redox decomposition of H2O2 in DMSO solution, compounds 10 and 18 were obtained in an overall yield of 80–90% with a 77:23 ratio, respectively

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

• dilution of compounds 1–6 dissolved in DMSO) were added to every well. EDTA was used as a reference and dissolved in water. The microtiter plate was gently shaken for 4 h at room temperature. After this incubation period the remaining CAS–Fe3+ complex in each well was quantified by measuring the absorbance

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• . DMSO was introduced as a co-solvent to promote the SN2-type reaction, and the dibromide 49 was smoothly hydrolyzed site-selectively to the monohydroxy product 50, which was fixed in an unsymmetrical manner in the cavitand. The bromide terminal was hence protected deep within the cavity of the cavitand

• host E from further hydrolysis, despite the addition of 10 equivalents DMSO after 2 days or even after one month. The experiment without the cavitand host produced a mixture of different products, and the dibromide was fully converted to the dihydroxy product after prolonging the reaction time or

• increasing DMSO concentration, without the detection of any monohydrolyzed product. This work further demonstrated the striking ability of the water-soluble cavitand to mediate site-selective reactions. Conclusion To summarize, we have reviewed various site-selective reactions mediated by molecular

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 25) [38]. The coupling products by reaction of phenylacetylene and various aryl halides were obtained in moderate to good yields in the presence of this green catalyst with 4 equivalents of KOH as the base in DMSO at 140 °C. Without any decrease in the catalytic activity, the catalyst could be

Flow synthesis of oxadiazoles coupled with sequential in-line extraction and chromatography

• Kian Donnelly and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 232–239, doi:10.3762/bjoc.18.27

• approach. This entails the use of a heated packed-bed reactor filled with solid K2CO3 as a base. Using DMSO as solvent, this flow method generates the target heterocycles within short residence times of 10 minutes and in yields up to 93%. Scale-up of this flow process was achieved (34 mmol/h) and featured

• solubility only being observed in DMF and DMSO. Despite the slightly lower yield observed using DMF (entry 8, Table 2), it provided the option of a co-solvent system in situations where solubility in DMSO is insufficient. A variety of acyl hydrazones were subsequently synthesised from the corresponding

• and an additional organic solvent could be introduced. As the reaction is carried out in DMSO, which is water soluble, an additional organic solvent was required to isolate the desired product from the aqueous phase. There are various examples of in-line separations published in the literature [37

Glycosylated coumarins, flavonoids, lignans and phenylpropanoids from Wikstroemia nutans and their biological activities

• Meifang Wu,
• Xiangdong Su,
• Yichuang Wu,
• Yuanjing Luo,
• Ying Guo and
• Yongbo Xue

Beilstein J. Org. Chem. 2022, 18, 200–207, doi:10.3762/bjoc.18.23

• two spin-spin systems of H-3'/H-4' and H-5'/H-6' (substructure B) depicted in the 1H-1H COSY of 1. Although the direct evidence between substructures A and B was missing, to our delighted, the key ROESY correlation of H-5/H-8' (Figure 3 and Supporting Information File 1, Figure S34, recorded in DMSO

• . The ROESY spectrum (Supporting Information File 1, Figure S34, recorded in DMSO-d6) showed correlations of H-3'' and H-1'' /H-5''/HO-4'', indicating the ᴅ-configuration of glucose, while the ROESY correlations of H-1'''/H-3'''/H-5''', H-3'''/H-5''', and H-2'''/H-4''' implied the xylose should be in ᴅ

• key correlations observed in the 1H-1H COSY (bold bonds), HMBC (blue) correlations of 1 (recorded in pyridine-d5, 600 MHz). The key correlations observed in the 1H-1H COSY (bold bonds), HMBC (blue), ROESY (red) of 1 (recorded in DMSO-d6, 800 MHz). 1H and 13C NMR Spectroscopic Data for 1 (δ in ppm, J

Synthesis and late stage modifications of Cyl derivatives

• Phil Servatius and
• Uli Kazmaier

Beilstein J. Org. Chem. 2022, 18, 174–181, doi:10.3762/bjoc.18.19

• the removal of metathesis catalysts is the formation of Ru-DMSO complexes, which do not eluate from a silica column [56]. This allowed us to remove at least the Ru contamination, but we were unable to subject 12 to further modifications such as cross metathesis or thiol-ene click reactions due to poor

Tenacibactins K–M, cytotoxic siderophores from a coral-associated gliding bacterium of the genus Tenacibaculum

• Yasuhiro Igarashi,
• Yiwei Ge,
• Tao Zhou,
• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku and
• Agus Trianto

Beilstein J. Org. Chem. 2022, 18, 110–119, doi:10.3762/bjoc.18.12

• adduct [M + Na]+ at m/z 678.4412 (Δ + 0.0 mmu for C33H61N5O8Na). Analysis of 13C NMR and HSQC spectroscopic data obtained in DMSO-d6 established the presence of five carbonyl carbons (δC 166.2, 168.6, 171.0, 171.5, 172.0), two sp2 methines (δC 119.8, 144.5), one sp3 methine (δC 27.5), two magnetically

• temperature, which was eventually attributed to the accelerated dissociation of the neighbouring hydroxamate group in a polar aprotic solvent, DMSO-d6. The isobutyl fragment showed HMBC correlations to two methylenic carbons δC 26.9 (C4) and 29.4 (C5), which provided an isohexyl fragment (Table 1). The

• succinylcadaverine unit was not proven due to the lack of relevant HMBC correlations in DMSO-d6. However, when measured in a mixed solvent (CDCl3/CD3OD 3:7), the peak shape of H13 was sharpened and HMBC correlations from both of the olefinic protons and the aminomethylene H16 to a carbonyl carbon (C14: δC 166.2

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

• and reported that they were unable to obtain 4-arylamino-1,2-naphthoquinones from β-NQSNa but that these derivatives can be readily prepared from 4-ethoxy-1,2-naphthoquinone. Similarly, Yano and co-workers [72] studied the tautomeric equilibrium of 4-arylamino-1,2-naphthoquinones in DMSO-d6, pyridine

Bifunctional thiourea-catalyzed asymmetric [3 + 2] annulation reactions of 2-isothiocyanato-1-indanones with barbiturate-based olefins

• Jiang-Song Zhai and
• Da-Ming Du

Beilstein J. Org. Chem. 2022, 18, 25–36, doi:10.3762/bjoc.18.3

• spectra were measured at 100 MHz with a 400 MHz spectrometer or at 176 MHz with a 700 MHz spectrometer, chemical shifts are reported in δ (ppm) units relative to tetramethylsilane and referenced to solvent peak (CDCl3, δ = 77.00 ppm; DMSO-d6, δ = 39.43 ppm). High-resolution mass spectra were measured with

Study on the interactions between melamine-cored Schiff bases with cucurbit[n]urils of different sizes and its application in detecting silver ions

• Jun-Xian Gou,
• Yang Luo,
• Xi-Nan Yang,
• Wei Zhang,
• Ji-Hong Lu,
• Zhu Tao and
• Xin Xiao

Beilstein J. Org. Chem. 2021, 17, 2950–2958, doi:10.3762/bjoc.17.204

• mmol, 3.66 g) in benzene (30 mL) was added under stirring, then reflux overnight. The pink powder was formed and washed with warm water to get the pure compound 1. 1H NMR (DMSO-d6) δ 12.1 (s, 3H), 9.76 (s, 3H), 7.80 (d, 6H), 7.08 (d, 6H), 4.06 (t, 6H), 2.40 (t, 6H), 1.93 (m, 6H) ppm. The synthesis of 2

• NMR (DMSO-d6) δ 9.82 (s, 3H), 7.82 (d, 6H), 7.07 (d, 6H), 7.08 (d, 6H), 4.04 (m, 14H), 1.95 (m, 9H), 1.13 (t, 12H) ppm. The synthesis of TBT: Compound 2 (0.780 g, 1.0 mmol)) and NaOH (0.27 g, 6.75 mmol) were combined in a 1:1 solution of acetonitrile and water (20 mL) and refluxed for 4 h. The mixture

Unsaturated fatty acids and a prenylated tryptophan derivative from a rare actinomycete of the genus Couchioplanes

• Shun Saito,
• Kanji Indo,
• Naoya Oku,
• Hisayuki Komaki,
• Masashi Kawasaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2939–2949, doi:10.3762/bjoc.17.203

• spectrophotometer. IR spectra were measured on a PerkinElmer Spectrum 100. NMR spectra were obtained on a Bruker AVANCE II 500 or AVANCE NEO 500 spectrometer in DMSO-d6 or CDCl3, and referenced to the residual solvent signals (δH 2.50, δC 39.5 for DMSO-d6; δH 7.26, δC 77.2 for CDCl3). HR–ESI–TOFMS spectra were

• silica gel thin-layer plate (Kieselgel 60F254; Merck Co.) developed by a mixture of CHCl3/MeOH (5:1). Extraction of the collected silica gel powder with MeOH gave (R)-PGME amide 6a (0.5 mg). (R)-PGME amide 6a: 1H NMR (500 MHz, DMSO-d6) δ 10.61 (s, 1H, NH-1), 7.01 (s, 1H, H-2), 7.46 (d, J = 8.1 Hz, 1H, H

• , 6b (0.4 mg) was prepared from 1 and (S)-PGME. (S)-PGME amide 6b: 1H NMR (500 MHz, DMSO-d6) δ 10.64 (s, 1H, NH-1), 7.07 (d, J = 2.5 Hz, 1H, H-2), 7.53 (d, J = 8.0 Hz, 1H, H-4), 6.80 (d, J = 8.1 Hz, 1H, H-5), 2.88 (dd, J = 14.8, 9.5 Hz, 1H, H-8a), 3.06 (dd, J = 14.8, 4.8 Hz, 1H, H-8b), 4.68 (m, 1H, H-9

A two-phase bromination process using tetraalkylammonium hydroxide for the practical synthesis of α-bromolactones from lactones

• Yuki Yamamoto,
• Akihiro Tabuchi,
• Kazumi Hosono,
• Takanori Ochi,
• Kento Yamazaki,
• Shintaro Kodama,
• Akihiro Nomoto and
• Akiya Ogawa

Beilstein J. Org. Chem. 2021, 17, 2906–2914, doi:10.3762/bjoc.17.198

• system, with the reaction time successfully reduced to 1 h (Table 2, entries 1–5). The use of a co-solvent to increase the solubility of 2a was investigated in detail; DMSO was found to be the most effective solvent, with 3a produced in 82% yield (Table 2, entries 5–12). We next optimized the base used

• + as the nucleophiles in the two-phase system (Scheme 6). To a three-necked flask were added 2a (2.0 mmol), DMSO (2 mL), H2O (4 mL), CHCl3 (10 mL), and n-Bu4N+OH− (1.2 equiv in aqueous solution), and stirred vigorously for 10 min at 25 °C. Then, a solution of PhS−Na+ (1.2 mmol) in H2O (4 mL) was slowly

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

• 74. Hydrolysis of the imine affords the final product 69. In 2020, Sun and Liu reported the iminyl cyclization could also be achieved with DMSO as a methyl-radical precursor [88]. In 2017, the Zhu group developed an Fe(acac)3-catalyzed cyanoalkylative dearomatization of N-phenylcinnamamides 75 for

Biological properties and conformational studies of amphiphilic Pd(II) and Ni(II) complexes bearing functionalized aroylaminocarbo-N-thioylpyrrolinate units

• Samet Poyraz,
• Samet Belveren,
• Sabriye Aydınoğlu,
• Mahmut Ulger,
• Abel de Cózar,
• Maria de Gracia Retamosa,
• Jose M. Sansano and
• H. Ali Döndaş

Beilstein J. Org. Chem. 2021, 17, 2812–2821, doi:10.3762/bjoc.17.192

• ). To obtain an initial concentration of 1000 μg/mL, the novel synthesized compounds were dissolved in DMSO to prepare stock solutions and then, 0.22 μm membrane filters were used to sterilization of the compounds. Serial two-fold dilutions of the compounds and ampicillin (standard reference drug) were

• concentration of 1000 μg/mL, stock solutions of the compounds were dissolved in DMSO. In a 96-well microtiter plate, a two-fold dilution series of the compounds and reference drugs were prepared in 100 μL of 7H9-S medium. A 100 μL of H37Rv standard strain working solution was added in microtiter plate wells and

• then, 250–0.12 μg/mL final concentration ranges of the compounds were obtained. In each anti-TB activity determination, a sterility control (without H37Rv working solution) and a growth control (containing no antibiotics) were included in each plate. Effects of DMSO were controlled by inoculated broth

Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases

• Inaiá O. Rocha,
• Yuri G. Kappenberg,
• Wilian C. Rosa,
• Clarissa P. Frizzo,
• Nilo Zanatta,
• Marcos A. P. Martins,
• Isadora Tisoco,
• Bernardo A. Iglesias and
• Helio G. Bonacorso

Beilstein J. Org. Chem. 2021, 17, 2799–2811, doi:10.3762/bjoc.17.191

• , 4-NO2C6H4, and 2-furyl, and R1-substituents are 5-NEt2, 5-OCH3, 4-Br, and 4-NO2. Complementarily, the Schiff bases showed low to good quantum fluorescence yield values in CHCl3 (Φf = 0.12–0.80), DMSO (Φf = 0.20–0.75) and MeOH (Φf = 0.13–0.85). Higher values of Stokes shifts (SS) were observed in

• more polar solvents (DMSO; 65–150 nm and MeOH; 65–130 nm) than in CHCl3 (59–85 nm). Compounds 3 presented good stability under white-LED irradiation conditions and moderate ROS generation properties were observed. Keywords: photophysical properties; photostability; quinoline; ROS generation; Schiff

• the series of compounds 3aa–fa and 3bb–be was carried out using chloroform (CHCl3), methanol (MeOH) or dimethyl sulfoxide (DMSO) solutions. As comparison, the UV–vis absorption spectra of compounds 3ea and 3be, which contain the nitro group in two different ring positions of the molecules recorded in

The PIFA-initiated oxidative cyclization of 2-(3-butenyl)quinazolin-4(3H)-ones – an efficient approach to 1-(hydroxymethyl)-2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-ones

• Alla I. Vaskevych,
• Nataliia O. Savinchuk,
• Ruslan I. Vaskevych,
• Eduard B. Rusanov,
• Oleksandr O. Grygorenko and
• Mykhailo V. Vovk

Beilstein J. Org. Chem. 2021, 17, 2787–2794, doi:10.3762/bjoc.17.189

• Vertex 70 spectrometer in KBr pellets. The NMR spectra were recorded with Varian VXR-300 (400, 500, 600) instruments (300, 400, 600 MHz for 1H, 188 MHz for 19F and 100, 125, 150 MHz for 13C) in CDCl3 and DMSO-d6 solutions, with TMS as an internal standard. Multiplets were assigned as s (singlet), d

• (7a) [59]: Prepared using amide 10a (218 mg, 1 mmol, 1 equiv). Light brown powder (142 mg, 0.71 mmol, 71%). Mp: 177–178 °C; 1H NMR (400 MHz, DMSO-d6) δ 12.18 (s, 1H, NH), 8.08 (d, J = 8.0 Hz, 1H, ArH), 7.77 (t, J = 8.0 Hz, 1H, ArH), 7.60 (d, J = 8.0 Hz, 1H, ArH), 7.46 (t, J = 7.6 Hz, 1H, ArH),5.92

• –5.82 (m, 1H, CH), 5.07 (d, J = 17.2 Hz, 1H, =CH2), 4.98 (d, J = 10.4 Hz, 1H, =CH2), 2.70 (t, J = 7.2 Hz, 2H, CH2), 2.49–2.47 (m, 2H, CH2); 13C NMR (125 MHz, DMSO-d6) δ 161.8, 156.7, 148.9, 137.2, 134.2, 126.8, 125.9, 125.7, 120.9, 115.5, 33.7, 30.6; HRMS–ESI (m/z): [M + H]+ calcd for C12H12N2O

Synthesis of new pyrazolo[1,2,3]triazines by cyclative cleavage of pyrazolyltriazenes

• Nicolai Wippert,
• Martin Nieger,
• Claudine Herlan,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2021, 17, 2773–2780, doi:10.3762/bjoc.17.187

• chains to the pyrazole moiety. The addition of several aliphatic bromides or iodides 14 in combination with potassium or cesium carbonate in DMSO gave a mixture of the regioisomeric compounds 12 and 13 due to the addition of the alkyl substituents to one of both pyrazole-nitrogen atoms. As shown in Table

• of the target compounds of class 5 were chosen as they were available in sufficient amounts and showed no decomposition during storage and dilution in DMSO. Also, most of the intermediates showed no reduction of cell viability; however, compounds 9b, 12b,c, 13a,b, and 13f–h showed some cytotoxic

• , failed under similar procedures. Abbreviations TFA, trifluoroacetic acid; DMSO, dimethyl sulfoxide; THF, tetrahydrofuran, TLC, thin-layer chromatography, LC–MS, liquid chromatography/mass spectrometry. Structural differences of several known (2–4) and so far unknown (5 and 6) pyrazolo[3,4-d][1,2,3]-3H