Scope of tetrazolo[1,5-a]quinoxalines in CuAAC reactions for the synthesis of triazoloquinoxalines, imidazoloquinoxalines, and rhenium complexes thereof

• Laura Holzhauer,
• Chloé Liagre,
• Olaf Fuhr,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2022, 18, 1088–1099, doi:10.3762/bjoc.18.111

• -donating properties or a positive mesomeric effect combined with a low steric demand, such as methyl and methoxy groups, the triazole product was preferably formed. Increased steric demand of the groups such as for isopropyl residues led to the formation of the imidazole product instead. When using

• conditions. The experiments were thus repeated with the methyl-, isopropyl- and phenyl-substituted compounds 11b, 11c, and 11e; again, increasing the amount of alkyne led to increased formation of the triazole product, especially for 11b and 11c. These observations match with the general mechanism of CuAAC

Electrochemical vicinal oxyazidation of α-arylvinyl acetates

• Yi-Lun Li,
• Zhaojiang Shi,
• Tao Shen and
• Ke-Yin Ye

Beilstein J. Org. Chem. 2022, 18, 1026–1031, doi:10.3762/bjoc.18.103

• substrate scope of this electrochemical oxyazidation reaction was investigated (Scheme 2). Enol acetates derived from various alkyl-substituted phenylacetones were generally well tolerated (3–9, 40–76% yields). The relatively low yield of the isopropyl-substituted one (7) was attributed to the competing

First example of organocatalysis by cathodic N-heterocyclic carbene generation and accumulation using a divided electrochemical flow cell

• Daniele Rocco,
• Ana A. Folgueiras-Amador,
• Richard C. D. Brown and
• Marta Feroci

Beilstein J. Org. Chem. 2022, 18, 979–990, doi:10.3762/bjoc.18.98

• (methyl, isopropyl and benzyl alcohols) were used and the results are shown in Table 3. All the experiments were carried out using a solution of 0.1 M of BMImBF4 in acetonitrile (20 mL) as catholyte, stainless steel as cathode, C/PVDF as anode, in a divided cell, under N2 atmosphere, at room temperature

• with the isopropyl alcohol the formation of the ester was only 37%, probably due to steric hindrance. In two cases (Table 3, entries 1 and 2) oxidation byproducts (esters 4a and 4b) were obtained, where the olefinic double bond is preserved. In contrast to the internal redox reactions of cinnamaldehyde

• (m, 10H), 5.13 (s, 2H), 2.99 (t, J = 7.0 Hz, 2H), 2.70 (t, J = 7.0 Hz, 2H) ppm; 13C NMR (CDCl3) δ 172.7, 140.4, 136.0, 128.6, 128.5, 128.3, 128.2, 126.3, 66.3, 35.9, 31.0 ppm. Isopropyl 3-phenylpropanoate (3c): Spectral data are consistent with those reported in the literature [44]. 1H NMR (CDCl3) δ

Electrochemical and spectroscopic properties of twisted dibenzo[g,p]chrysene derivatives

• Tomoya Imai,
• Ryuhei Akasaka,
• Naruhiro Yoshida,
• Toru Amaya and
• Tetsuo Iwasawa

Beilstein J. Org. Chem. 2022, 18, 963–971, doi:10.3762/bjoc.18.96

• strategy for preparing DBC derivatives using DBC-H with four isopropyl groups at X as a key template for the derivatization (Figure 1c). Based on this strategy, various substituents were introduced at Z to produce DBC-Br, DBC-Me, DBC-SMe, DBC-S(O)2Me, and DBC-Si (Figure 1c) [52]. The structures of all

• voltammogram of DBC-H exhibited a reversible, two-step, two-electron redox process, with Eox1 and Eox2 values of 0.34 V and 0.72 V, respectively (Figure 2a). The value of Eox1 is 0.06 V lower than that of MeO-DBC-1 which does not contain isopropyl groups. This is in contrast to MeO-DBC-3, in which four MeO

• groups are introduced in place of the isopropyl groups, which has a 0.06 V higher oxidation potential than that of MeO-DBC-1. This indicates that alkyl substituents in the X position are effective in stabilizing the radical cation, thus making it more susceptible to oxidation. Unlike DBC-H, an

Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides

• Jiaxi Xu

Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90

• group and the nature of its terminal substituents (aromatic phenyl and aliphatic isopropyl) are the crucial factors impacting the diastereoselectivity. Generally, the substrates with bulky R and aromatic phenyl terminal substituent in their allyl groups gave rise to the desired 1,5-dihydro-1,2

Efficient production of clerodane and ent-kaurane diterpenes through truncated artificial pathways in Escherichia coli

• Fang-Ru Li,
• Xiaoxu Lin,
• Qian Yang,
• Ning-Hua Tan and
• Liao-Bin Dong

Beilstein J. Org. Chem. 2022, 18, 881–888, doi:10.3762/bjoc.18.89

• -kaurene production were created. Next, DL10003–10006 were fermented in Lysogeny broth (LB) medium supplied with 1% glycerol, 6 mM ISO/DMAA 3:1, and 0.1 mM isopropyl β-ᴅ-1-thiogalactopyranoside (IPTG) inducer. In comparison with the negative control of wild-type E. coli BL21 (DE3), all strains successfully

Cathodic generation of reactive (phenylthio)difluoromethyl species and its reactions: mechanistic aspects and synthetic applications

• Sadanobu Iwase,
• Shinsuke Inagi and
• Toshio Fuchigami

Beilstein J. Org. Chem. 2022, 18, 872–880, doi:10.3762/bjoc.18.88

• both radical and anionic intermediates. In order to further clarify the reaction mechanism, the indirect cathodic reduction of compound 1 was performed in the presence of α-methylstyrene in MeCN containing cumene (iPrC6H5) and isopropyl alcohol (iPrOH). The former works as a hydrogen radical source

• -phthalonitrile as mediator in the presence of α-methylstyrene. Reaction of compound 1 with SmI2 in the presence and absence of α-methylstyrene. Indirect cathodic reduction of compound 1 with o-phthalonitrile in the presence of α-methylstyrene in MeCN containing cumene or isopropyl alcohol. Supporting

Synthesis of odorants in flow and their applications in perfumery

• Merlin Kleoff,
• Paul Kiler and
• Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

• SAC-13, alkylation of m-cresol with isopropanol proceeds via a Friedel–Crafts-type mechanism in much lower selectivity. In contrast, the authors proposed that employing γ-Al2O3 as Lewis acid catalyst, reaction of 39 and isopropanol leads to isopropyl ether 40. This intermediate undergoes a Fries-type

• = mass flow controller. Synthesis of thymol (41) from m-cresol (39) and isopropyl alcohol via Fries-type rearrangement of ether 40. Preparation of coumarin (46) by reaction of salicylaldehyde (44) with potassium acetate, acetic acid, and acetic anhydride at elevated temperature in two separated tube

Identification of the new prenyltransferase Ubi-297 from marine bacteria and elucidation of its substrate specificity

• Jamshid Amiri Moghaddam,
• Huijuan Guo,
• Karsten Willing,
• Thomas Wichard and
• Christine Beemelmanns

Beilstein J. Org. Chem. 2022, 18, 722–731, doi:10.3762/bjoc.18.72

• quantification: Plasmids containing the respective gene were transformed into E. coli BL21 and strains harboring the plasmid were cultivated in TB medium supplemented with kanamycin (60 µg mL−1). Cultures were grown at 37 °C to an OD600 of 0.8, then brought to 16 °C and isopropyl β-ᴅ-thiogalactoside (IPTG) was

Bioinspired tetraamino-bisthiourea chiral macrocycles in catalyzing decarboxylative Mannich reactions

• Hao Guo,
• Yu-Fei Ao,
• De-Xian Wang and
• Qi-Qiang Wang

Beilstein J. Org. Chem. 2022, 18, 486–496, doi:10.3762/bjoc.18.51

• linking components to afford Lewis base sites and also for introduction of chirality. Different alkyl substituents including methyl, n-propyl, isopropyl, and 3-pentyl were incorporated in order to tune the size and steric effect of the macrocyclic cavity and thus to enable diverse cavity environments

• on the reaction stereoselectivity. The cyclohexanediamine-linking macrocycles M1–M4 afforded the product with overall higher enantiomeric excess (ee) (Table 1, entries 1–4). Among which the isopropyl-substituted macrocycle M3 gave the best selectivity, i.e., 42% ee. This suggested a suitable crowding

Sesquiterpenes from the soil-derived fungus Trichoderma citrinoviride PSU-SPSF346

• Wiriya Yaosanit,
• Vatcharin Rukachaisirikul,
• Souwalak Phongpaichit,
• Sita Preedanon and
• Jariya Sakayaroj

Beilstein J. Org. Chem. 2022, 18, 479–485, doi:10.3762/bjoc.18.50

• , s, 2H), three sets of nonequivalent methylene protons (δH 3.40 and 3.30, each d, J = 16.8 Hz, 1H; δH 2.13 and 2.04, each m, 1H; δH 1.81 and 1.39, each m, 1H), and an isopropyl group (δH 1.71, m, 1H, and δH 0.95 and 0.82, each d, J = 6.9 Hz, 3H). The 13C NMR spectrum (Table 1) consisted of signals

• and 1.37, m, 1H; δH 1.84 and 1.64, each m, 1H), and an isopropyl group (δH 1.83, m, 1H, and δH 1.06 and 0.88, each d, J = 6.5 Hz, 3H). The 13C NMR spectrum (Table 1) consisted of signals for two carboxyl carbonyl carbons (δC 179.6 and 174.5), two quaternary carbons (one olefinic carbon, δC 150.2, and

• (δH 2.81), H-5/H-10 (δH 1.35), and Hab-9 (δH 1.84 and 1.64)/Hab-8 (δH 2.45 and 1.37) and H-10, and the HMBC correlations (Figure 2) from H3-12 (δH 1.06) and H3-13 (δH 0.88) of the isopropyl group to C-10 (δC 49.0) and Hab-15 (δH 3.69 and 3.65) to C-6 (δC 51.4), C-7 (δC 83.4), and C-8 (δC 29.3) as well

The asymmetric Henry reaction as synthetic tool for the preparation of the drugs linezolid and rivaroxaban

• Martin Vrbický,
• Karel Macek,
• Jaroslav Pochobradský,
• Jan Svoboda,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2022, 18, 438–445, doi:10.3762/bjoc.18.46

• performed on sub-millimolar scales in isopropyl alcohol (IPA). The obtained products 21–26 were separated from the starting aldehydes 15–20 by column chromatography. The reaction conditions (i.e., temperature, reaction time, amount of catalyst, and solvent) were adopted from the pilot study [12] for

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

• ]pentane (BCP) building blocks [36], we investigated their use in the oxadiazole-forming reaction. The BCP acid chloride 5 was synthesised from [1.1.1]propellane (3) via the photochemical reaction with isopropyl 2-chloro-2-oxoacetate (Scheme 4). The corresponding BCP acyl hydrazone was then obtained

Anomeric 1,2,3-triazole-linked sialic acid derivatives show selective inhibition towards a bacterial neuraminidase over a trypanosome trans-sialidase

• Peterson de Andrade,
• Sanaz Ahmadipour and
• Robert A. Field

Beilstein J. Org. Chem. 2022, 18, 208–216, doi:10.3762/bjoc.18.24

• ). Incubation at 37 °C along with shaking (200 rpm) was continued until optical density (OD600) reached 0.6. Heterologous protein expression was induced by adding isopropyl β-ᴅ-1-thiogalactopyranoside (IPTG) to a final concentration of 1 mM and incubating for 4 hours at 30 °C with shaking (180 rpm). The cells

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

• . The 1H NMR spectrum of 2 was similar to those of 1 in overall (Table 1 and Table 2). One major difference was a replacement of the triplet methyl peak in 1 by a six proton-equivalent doublet methyl peak, which suggested an isopropyl-terminated structure. This was proven by a COSY correlation between

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• ratio of 86:14 and high enantiomeric purity of 95:5 er for the major diastereomer (Table 1, entry 1). Using chloroform/isopropyl alcohol 9:1 as the solvent mixture afforded after 120 hours, aldehyde 10a in 45% yield with 83:17 dr and 97:3 er (Table 1, entry 2). The Michael addition in methanol catalyzed

Allylic alcohols and amines by carbenoid eliminative cross-coupling using epoxides or aziridines

• Matthew J. Fleming and
• David M. Hodgson

Beilstein J. Org. Chem. 2021, 17, 2385–2389, doi:10.3762/bjoc.17.155

• stereoselectivity. However, neither isopropyl or neopentyl benzylic ethers 26 and 27 [23][24] led to a significant change in the E/Z ratio for cinnamylamine 23 (Scheme 11). Conclusion In summary, we report a new, convergent access to allylic alcohols and amines. The process proceeds by selective cross-coupling of α

• epoxide 5. Synthesis of vinylsilane 14. Allylic alcohol 8 from epoxide 5 and sulfone 15. Allylic amines from aziridine 17. Cyclopropylidene synthesis from aziridine 20. Cinnamylamine 23 synthesis from aziridine 17. Cinnamylamine 23 synthesis from isopropyl or neopentyl benzylic ethers 26 and 27

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

• Sumana Mandal,
• Raju D. Chaudhari and
• Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

• piperidine derivatives were also synthesized by Hg(II)-salt-induced cyclization. N-Isopropyl-1-aminohex-4-ene (23) on treatment with 1 equiv HgCl2 followed by reduction with NaBH4 yielded pyrrolidine 24 and piperidine derivative 25 in the ratio of 7:3 [50]. N-Methylaniline derivative 26 undergoes cyclization

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

• macromolecule is in solution. The best known example of a phase transition with an LCST is PNIPAAm with its hydrophilic isopropyl groups interacting with water molecules [48][97][98][99]. From a thermodynamic point of view, the hydrogen bonds between the polymer and the water molecules lead to a negative value

Preparation of mono-substituted malonic acid half oxyesters (SMAHOs)

• Tania Xavier,
• Sylvie Condon,
• Christophe Pichon,
• Erwan Le Gall and
• Marc Presset

Beilstein J. Org. Chem. 2021, 17, 2085–2094, doi:10.3762/bjoc.17.135

• step, the opening of the Meldrum's acid moiety with an alcohol 8. Indeed, this reaction was achieved under simple conditions and led to the desired products in useful yields, only limited by partial in situ decarboxylation. This strategy thus allowed the preparation of the isopropyl (4ch, 93%) and

Enantioenriched α-substituted glutamates/pyroglutamates via enantioselective cyclopropenimine-catalyzed Michael addition of amino ester imines

• Zara M. Seibel,
• Jeffrey S. Bandar and
• Tristan H. Lambert

Beilstein J. Org. Chem. 2021, 17, 2077–2084, doi:10.3762/bjoc.17.134

• isopropyl completely suppressed reactivity (Table 2, entry 8). On the other hand, allyl (Table 2, entry 9) and propargyl (Table 2, entry 10) groups proved to viable substituents, leading to the products in good yield and high enantioselectivities. Of course, these two functional groups provide convenient

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

• attention. Nevertheless, β(1–6)-linked GlcN oligosaccharides may act as potential antitumor and immunostimulating agents [262] and could become important synthetic targets. The synthesis of a β(1–6)-linked 9mer was demonstrated, using an isopropyl thioglycoside donor [262]. Convergent [262] as well as

Fritsch–Buttenberg–Wiechell rearrangement of magnesium alkylidene carbenoids leading to the formation of alkynes

• Tsutomu Kimura,
• Koto Sekiguchi,
• Akane Ando and
• Aki Imafuji

Beilstein J. Org. Chem. 2021, 17, 1352–1359, doi:10.3762/bjoc.17.94

• )-substituted 1-chlorovinyl p-tolyl sulfoxide 2a was added to isopropylmagnesium chloride in toluene at −78 °C, and the mixture was warmed to 0 °C for 2 h (Table 1, entry 1). Excess isopropylmagnesium chloride (3.5 equivalents) was necessary for the complete consumption of the sulfoxide. As a result, isopropyl

• isopropylmagnesium chloride in 99% yield (Table 2, entry 1). In contrast, the treatment of 2,2-dialkyl-substituted sulfoxide 2c with isopropylmagnesium chloride gave a complex mixture including alkene 11 with an isopropyl group, which arose from the SNV reaction, in 35% yield (Table 2, entry 2, and Scheme 5). 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

Heterogeneous photocatalytic cyanomethylarylation of alkenes with acetonitrile: synthesis of diverse nitrogenous heterocyclic compounds

• Guanglong Pan,
• Qian Yang,
• Wentao Wang,
• Yurong Tang and
• Yunfei Cai

Beilstein J. Org. Chem. 2021, 17, 1171–1180, doi:10.3762/bjoc.17.89

• , delivering the corresponding regioisomers 8l and 8l’ in 62% with 1:1.6 ratio. Moreover, the naphthalene and tetrahydroisoquinoline-derived acrylamides were also compatible, giving the polycyclic products 8m and 8n in 77% and 70%, respectively. Additionally, protecting groups such as isopropyl, benzyl, or