Heterogeneous acidic catalysts for the tetrahydropyranylation of alcohols and phenols in green ethereal solvents

• Ugo Azzena,
• Massimo Carraro,
• Gloria Modugno,
• Luisa Pisano and
• Luigi Urtis

Beilstein J. Org. Chem. 2018, 14, 1655–1659, doi:10.3762/bjoc.14.141

• -isopropyl-5-methylcyclohexanol ((−)-menthol, 1i). The reaction afforded an almost 1:1 mixture of only two diastereoisomers as determined by 1H and 13C NMR analysis of the crude reaction mixture, thus suggesting that it occurs with no epimerization at C1. This result was confirmed by submitting compound 3i

Enantioselective phase-transfer catalyzed alkylation of 1-methyl-7-methoxy-2-tetralone: an effective route to dezocine

• Ruipeng Li,
• Zhenren Liu,
• Liang Chen,
• Jing Pan and
• Weicheng Zhou

Beilstein J. Org. Chem. 2018, 14, 1421–1427, doi:10.3762/bjoc.14.119

• was determined by HPLC using a chiral column (Daicel chiral AY-H) with (hexane/isopropyl alcohol 90:10) as eluents, detected at 280 nm. Specific rotations were determined on a Rudolph Research Analytical automatic polarimeter IV. All reactions were monitored by TLC, which were carried out on silica

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• A has shown much higher affinity than parent distamycin A (preferential selectivity towards G·C sites) due to the presence of an isopropyl-substituted thiazole ring, which makes the molecule more hydrophobic [54]. Recently, a small set of analogs of thiazotropsin was designed and synthesized to

• binders [110]. Crystal structure data revealed that nitro groups and ester moieties in conjugates 44 and 45 are coplanar with the pyrrole ring, whereas the isopropyl fragment in conjugate 46 lies out of the pyrrole plane. Coplanarity extends to the second pyrrole ring in case of conjugate 47 and all these

2-Iodo-N-isopropyl-5-methoxybenzamide as a highly reactive and environmentally benign catalyst for alcohol oxidation

• Takayuki Yakura,
• Tomoya Fujiwara,
• Akihiro Yamada and
• Hisanori Nambu

Beilstein J. Org. Chem. 2018, 14, 971–978, doi:10.3762/bjoc.14.82

• to benzophenone in the presence of Oxone® (2KHSO5·KHSO4·K2SO4) as a co-oxidant at room temperature. A study on the substituent effect of the benzene ring of N-isopropyl-2-iodobenzamide on the oxidation revealed that its reactivity increased in the following order of substitution: 5-NO2 < 5-CO2Me, 3

• iodobenzene and 4-iodobenzenesulfonic acid (12) as catalysts [58][59]. As part of our study on the development of multifunctionalized organocatalysts based on hypervalent iodine chemistry [60][61][62][63][64][65][66], we found that N-isopropyl-2-iodobenzamide (13), when utilized as a catalyst with Oxone® at

• of the iodobenzamides depends on the ortho-relationship of the iodine atom to the amide group. Therefore, we then investigated N-isopropyl-2-iodobenzamides that have an additional functional group on the benzene ring. Based on the results of our studies on phenol oxidation [60][62] and Ishihara’s [52

Crystal structure of the inclusion complex of cholesterol in β-cyclodextrin and molecular dynamics studies

• Elias Christoforides,
• Andreas Papaioannou and
• Kostas Bethanis

Beilstein J. Org. Chem. 2018, 14, 838–848, doi:10.3762/bjoc.14.69

• molecule protrudes from the primary rim of host B. The hydrogens of its secondary C24 atom form C–H···O bonds with partially occupied water molecule sites located in the interdimeric space. The isopropyl group of the guest projects through the primary hydroxy rim of host B, clearly higher disordered than

• complex, the bulky cholesterol molecule with a length of about 16.5 Å is encapsulated with its hydroxy group and isopropyl terminal groups protruding from the primary hydroxy rim of the hosts and directly bonded with the hosts of the adjacent complex units, its tight fit in the β-CD dimeric cavity further

• . CHL is found encapsulated axially in a head-to-head β-CD dimer (host A and host B), tightly bound via numerous van der Waals and C–H···O interactions to the inner dimeric host cavity. The hydroxy group and the isopropyl group of the guest protrude from the primary rim of the host A and host B

Chlorination of phenylallene derivatives with 1-chloro-1,2-benziodoxol-3-one: synthesis of vicinal-dichlorides and chlorodienes

• Zhensheng Zhao and
• Graham K. Murphy

Beilstein J. Org. Chem. 2018, 14, 796–802, doi:10.3762/bjoc.14.67

• -dichlorides. Substrates with α-ethyl (2r) and α-isopropyl (2s) substituents reacted similarly, giving chlorinated products in 63–65% yield. Lastly, vinylidene 2t gave chlorodiene 4t as the sole product in 74% yield. As with alkoxy substrate 2m, the α-methylated substrates 2u and 2v possessing methoxy group(s

Biocatalytic synthesis of the Green Note trans-2-hexenal in a continuous-flow microreactor

• Morten M. C. H. van Schie,
• Tiago Pedroso de Almeida,
• Gabriele Laudadio,
• Florian Tieves,
• Elena Fernández-Fueyo,
• Timothy Noël,
• Isabel W. C. E. Arends and
• Frank Hollmann

Beilstein J. Org. Chem. 2018, 14, 697–703, doi:10.3762/bjoc.14.58

• pre-culture to an OD of 0.05 and grown at 37 °C and 180 rpm. At an OD600 of 0.8, 1 mM isopropyl β-D-thiogalactopyranoside (IPTG) was added and the cultures were incubated for additional 4 h at 37 °C and 180 rpm. The bacterial pellets, obtained after harvesting the cells, were re-suspended in a total

Diastereoselective auxiliary- and catalyst-controlled intramolecular aza-Michael reaction for the elaboration of enantioenriched 3-substituted isoindolinones. Application to the synthesis of a new pazinaclone analogue

• Romain Sallio,
• Stéphane Lebrun,
• Frédéric Capet,
• Francine Agbossou-Niedercorn,
• Christophe Michon and
• Eric Deniau

Beilstein J. Org. Chem. 2018, 14, 593–602, doi:10.3762/bjoc.14.46

• , substituted at the benzyl para-position by isopropyl and CF3 groups, gave good results with 76 and 74% de (Table 2, entries 9 and 10). Dimeric and trimeric organocatalysts 19 and 20 based on a cinchonine core did not enhance the reaction diastereoselectivity (Table 2, entries 15 and 16). Finally, by

Copper-catalyzed asymmetric methylation of fluoroalkylated pyruvates with dimethylzinc

• Kohsuke Aikawa,
• Kohei Yabuuchi,
• Kota Torii and
• Koichi Mikami

Beilstein J. Org. Chem. 2018, 14, 576–582, doi:10.3762/bjoc.14.44

• as isopropyl, cyclopentyl, and cyclohexyl led to a higher level of enantioselectivities (90–94% ee), compared to the corresponding ethyl ester 1a. In contrast, trifluoropyruvate 1f with an extremely bulky substituent caused a decrease of enantioselectivity. Ethyl difluoropyruvate (1g) and ethyl

Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• espintanol and (±)-schefflone starting from 6-((dibenzylamino)methyl)-3-isopropyl-2,4-dimethoxyphenol. The o-QM formed be trapped by 3-(dimethylamino)-5,5-dimethylcyclohex-2-en-1-one resulting in tetrahydro-1H-xanten-1-one 19 [70]. Starting from phenolic Mannich bases and 3-dimethylamino-2-cyclohexen-1-ones

One-pot sequential synthesis of tetrasubstituted thiophenes via sulfur ylide-like intermediates

• Jun Ki Kim,
• Hwan Jung Lim,
• Kyung Chae Jeong and
• Seong Jun Park

Beilstein J. Org. Chem. 2018, 14, 243–252, doi:10.3762/bjoc.14.16

• thiophenes (8aa–ai) were obtained in moderate to excellent yields (47–92%). When different 1,3-diketones were applied, the yields were affected by the keto–enol tautomer ratio. Alkyl substituents (isopropyl and cyclopropyl), which promote the enol forms of the ketones, afforded thiophenes 8aj and 8ak in good

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• ’ = isopropyl, 42). The reactions were carried out with various metal catalysts in acetic acid and acetonitrile solvents but reactions carried in acetic acid in presence of silica gel impregnated with indium trichloride provided the best results. Júnior et al. [53] also used N,N-dimethylpyrazoylimines 42 with N

Reactivity of bromoselenophenes in palladium-catalyzed direct arylations

• Aymen Skhiri,
• Ridha Ben Salem,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2017, 13, 2862–2868, doi:10.3762/bjoc.13.278

• heteroarenes in the presence of 2 mol % Pd(OAc)2, KOAc as the base in DMA at 90 °C (Scheme 2). The reaction of 2-isopropyl-4-methylthiazole gave the desired product 2 in 82% yield. Conversely, low yields in the target products 3–5 were obtained for the reactions with thiophene-2-carbonitrile, 2-chlorothiophene

Reagent-controlled regiodivergent intermolecular cyclization of 2-aminobenzothiazoles with β-ketoesters and β-ketoamides

• Irwan Iskandar Roslan,
• Kian-Hong Ng,
• Gaik-Khuan Chuah and
• Stephan Jaenicke

Beilstein J. Org. Chem. 2017, 13, 2739–2750, doi:10.3762/bjoc.13.270

• % yields, respectively. A variety of β-ketoesters and β-ketoamides were tested using the optimized conditions. Alkyl acetoacetates, including pentyl, isopropyl, tert-butyl and methoxyethyl, reacted smoothly with excellent yields (Scheme 2, 3l–3o). β-Ketoamides were well tolerated (Scheme 2, 3h, 3p and 3q

• yields were obtained for β-ketoesters with n-propyl and n-butyl moieties at the C-4 carbon (Scheme 3, 5l and 5m). Bulkier isopropyl and tert-butyl substituents were less well tolerated, with significantly lower yields (Scheme 3, 5n and 5o). The best yield of 99% was obtained when ethyl 4,4,4

Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

• Grzegorz Mlostoń and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

• from the corresponding precursors 17 with methyl, ethyl and isopropyl esters of type E- and Z-1 [19][33][34][35][36]. Remarkably, the reactions of (E)- and (Z)-1b with thiocarbonyl S-methanides 16b-e, in contrast to the corresponding S-isopropanide 16a (Scheme 5), occurred without formation of

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• are methyl, ethyl, isopropyl or, occasionally, n-butyl [127]. This observation is likely explained by the synthetic methods employed to prepare phosphonates that frequently made use of the Arbuzov reaction [128] involving the commercially available trimethyl, triethyl or triisopropyl phosphite [129

Preactivation-based chemoselective glycosylations: A powerful strategy for oligosaccharide assembly

• Weizhun Yang,
• Bo Yang,
• Sherif Ramadan and
• Xuefei Huang

Beilstein J. Org. Chem. 2017, 13, 2094–2114, doi:10.3762/bjoc.13.207

• the reaction mixture. The Gin group established a preactivation glycosylation procedure using glycosyl hemiacetals [36]. As an example, the hemiacetal donor 21 was preactivated with Tf2O and diphenyl sulfoxide (Ph2SO) at −40 °C. This was followed by the addition of the acceptor isopropyl alcohol

Main group mechanochemistry

• Agota A. Gečiauskaitė and
• Felipe García

Beilstein J. Org. Chem. 2017, 13, 2068–2077, doi:10.3762/bjoc.13.204

• adamantoid P4(NR)6 frameworks. These species are synthesised by direct reaction of PCl3 with sterically unhindered amines RNH2 (R= Me, Et, iPr, Bz) [101] or by isomerization of their less thermodynamically-stable macrocyclic [{P(μ-NR)}2(μ-NR)]2 counterparts. In the latter, the isopropyl (iPr) substituted

Selective enzymatic esterification of lignin model compounds in the ball mill

• Ulla Weißbach,
• Saumya Dabral,
• Laure Konnert,
• Carsten Bolm and
• José G. Hernández

Beilstein J. Org. Chem. 2017, 13, 1788–1795, doi:10.3762/bjoc.13.173

• 3). Notably, ethyl acetate (2d), isopropyl acetate (2e) and allyl acetate (2f) were suitable for the enzymatic esterification of erythro-1a as well, although to a lesser extent (Table 2, entries 4–6). Finally, lower and no reactivity was observed using tert-butyl acetate (2g) and acetic acid (2h) as

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

Syntheses of 3,4- and 1,4-dihydroquinazolines from 2-aminobenzylamine

• Jimena E. Díaz,
• Silvia Ranieri,
• Nadia Gruber and
• Liliana R. Orelli

Beilstein J. Org. Chem. 2017, 13, 1470–1477, doi:10.3762/bjoc.13.145

• account the boiling points of the alkylating agents and the reactivity of each substrate. As expected, the reaction was selective toward the N-monoalkylation of the arylamino group in the presence of the amide. Satisfactory results were also obtained using the more hindered isopropyl iodide (Table 2

• in precursors 5. The cyclodehydration of acetamides 5a–c proceeded under mild reaction conditions (Table 4, entries 1–3), while acetamide 5d required a higher temperature probably due to the steric hindrance produced by the N-isopropyl moiety (Table 4, entry 4). A higher temperature and a longer

Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

• A. Michael Downey and
• Michal Hocek

Beilstein J. Org. Chem. 2017, 13, 1239–1279, doi:10.3762/bjoc.13.123

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

Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

• Vinila N. Viswanathan,
• Arun D. Rao,
• Upendra K. Pandey,
• Arul Varman Kesavan and
• Praveen C. Ramamurthy

Beilstein J. Org. Chem. 2017, 13, 863–873, doi:10.3762/bjoc.13.87

• substrates (Xinyan Technology Limited, Taiwan) were sequentially cleaned in deionized (DI) water with soap (Hellmanex III), DI water, isopropyl alcohol, acetone and water under sonication for ≈30 min each. The cleaned substrates were then dried with nitrogen gas. UV–ozone was performed on cleaned substrates

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• synthesized a series of novel imidazole-based phosphine ligands, and their effciency was carefully screened [23]. Among these ligands, the one with two isopropyl groups located at the phenyl ring (L3) was effective in converting aryl chlorides and bromides to the corresponding phenols in moderate to excellent

• facilitate C–H hydroxylation of benzoic acids and heteroarenes [55]. An amidation reaction between benzoic acid and 2-(pyridine-2-yl)isopropylamine gave N-(2-(pyridine-2-yl)isopropyl)benzamides, which could be hydroxylated at the ortho position in moderate to excellent yields. The reaction was promoted by a