A chemoselective and continuous synthesis of m-sulfamoylbenzamide analogues

• Arno Verlee,
• Thomas Heugebaert,
• Tom van der Meer,
• Pavel I. Kerchev,
• Frank Van Breusegem and
• Christian V. Stevens

Beilstein J. Org. Chem. 2017, 13, 303–312, doi:10.3762/bjoc.13.33

• )benzoic acid [15][16][17]. This synthetic approach is a two-step procedure and therefore needs two subsequent work-up steps, limiting the yield and resulting in a more time-consuming synthetic approach. Yang et al. [18] reported a one-pot synthetic strategy for m-sulfamoylbenzamide analogues starting from

Versatile synthesis of end-reactive polyrotaxanes applicable to fabrication of supramolecular biomaterials

• Atsushi Tamura,
• Asato Tonegawa,
• Yoshinori Arisaka and
• Nobuhiko Yui

Beilstein J. Org. Chem. 2016, 12, 2883–2892, doi:10.3762/bjoc.12.287

• polymer (elution volume: 3.7 mL) or α-CD (elution volume: 4.5 mL) in the SEC chart. Figure 1 shows the SEC chart of the crude products of the PEG-NH2/α-CD pseudopolyrotaxane treated with 4-(azidomethyl)benzoic acid (2a) in the presence of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride

• obtained from NOF Corporation (Tokyo, Japan). α-Cyclodextrin (α-CD) was obtained from Ensuiko Sugar Refining (Tokyo, Japan). 4-(Azidomethyl)benzoic acid was synthesized according to the previous report [27]. 4-Azidobenzoic acid, 4-methylbenzoic acid, p-(tert-butyl)phenylacetylene, and 2-(2-hydroxyethoxy

• temperature. After the reaction, the precipitate was collected by centrifugation and freeze-dried for 1 day to obtain a pseudopolyrotaxane as powder (yield 1.37 g). Then, 4-(azidomethyl)benzoic acid (106 mg, 597 μmol), DMT-MM (165 mg, 597 μmol), and the pseudopolyrotaxane were allowed to react in methanol (14

Synthesis of polyhydroxylated decalins via two consecutive one-pot reactions: 1,4-addition/aldol reaction followed by RCM/syn-dihydroxylation

• Michał Malik and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2016, 12, 2602–2608, doi:10.3762/bjoc.12.255

• allylic alcohols as substrates in Mitsunobu reactions can be a challenging task, some successful examples can be found in the literature [49][50]. However, the reaction with benzoic acid did not proceed at all, whereas application of p-nitrobenzoic acid yielded a complicated mixture of products. Therefore

Catalytic Wittig and aza-Wittig reactions

• Zhiqi Lao and
• Patrick H. Toy

Beilstein J. Org. Chem. 2016, 12, 2577–2587, doi:10.3762/bjoc.12.253

• as the reducing reagent to regenerate 33. Most recently they refined such reactions using 22 as the pre-catalyst, trimethoxysilane as the reducing reagent, and catalytic benzoic acid to facilitate phosphine oxide reduction [27]. At about the same time as the penultimate report by Werner and co

Synthesis and NMR studies of malonyl-linked glycoconjugates of N-(2-aminoethyl)glycine. Building blocks for the construction of combinatorial glycopeptide libraries

• Markus Nörrlinger,
• Sven Hafner and
• Thomas Ziegler

Beilstein J. Org. Chem. 2016, 12, 1939–1948, doi:10.3762/bjoc.12.183

• (ΔG‡r) using the Eyring model. The found ΔG‡r values (17.9–18.3 kcal/mol) were in good accordance with those of other known PNA-derivates (17.9–19 kcal/mol). The PNA-based glycoprotein building blocks described here will be used in combination with previously described benzoic acid-based glycopeptoids

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

• the two basic reaction products, benzoic acid was isolated as well (43%; Table 2, entry 9). By this means during the course of Rh(II)-catalyzed reactions of aroyldiazomethanes 2a–c, diazoketoesters 3a,b and diazodiketone 3c with aminoester 1, contrary to the similar reactions of diazoesters [15], two

• hydroperoxide G, which then converts into 1,2-dioxetane H [30]. Subsequent cleavage of σ-С–С and О–О bonds in the structure of dioxetane H gives rise to the formation of amides 4 or 7 and the appropriate рara-substituted benzoic acid, which was isolated in several cases from reaction mixtures. A leading role in

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• triethylamine. The obtained product 4-hydroxycyclohexen-2-one 273 releases benzoic acid through β-elimination under the basic conditions to give cyclohexadienone 274 (Scheme 83) [357]. The base-catalyzed isomerization of bicyclic saturated fulvene endoperoxides 275 is employed as one approach to the preparation

Towards potential nanoparticle contrast agents: Synthesis of new functionalized PEG bisphosphonates

• Souad Kachbi-Khelfallah,
• Maelle Monteil,
• Margery Cortes-Clerget,
• Evelyne Migianu-Griffoni,
• Jean-Luc Pirat,
• Olivier Gager,
• Julia Deschamp and
• Marc Lecouvey

Beilstein J. Org. Chem. 2016, 12, 1366–1371, doi:10.3762/bjoc.12.130

• PEG chain cleavage and the recovery of benzoic acid from alcohol 2. Besides, the mixture IBX/oxone gave the expected product inseparable of IBX byproducts. Only oxidation using TEMPO and BAIB furnished the pure corresponding carboxylic acid. Nevertheless, the low obtained yields encouraged us to test

Unconventional application of the Mitsunobu reaction: Selective flavonolignan dehydration yielding hydnocarpins

• Guozheng Huang,
• Simon Schramm,
• Jörg Heilmann,
• David Biedermann,
• Vladimír Křen and
• Michael Decker

Beilstein J. Org. Chem. 2016, 12, 662–669, doi:10.3762/bjoc.12.66

• reaction. We investigated the reaction under Mitsunobu conditions using the latter sequence of addition [10] for silibinin and benzoic acid, or 2,2-dimethyl-3-(nitrooxy)propanoic acid (7, Scheme 1), an NO-donor compound with several biological properties, e.g., vasorelaxation [27]. Compound 7 had initially

• 1 and 5). In absence of an acid, 2,3-dehydration did not occur even using excessive amounts of Ph3P and DIAD (Table 1, entries 7 and 8). In the absence of DIAD, silibinin was not converted into any other compound (Table 1, entry 9). Benzoic acid had been applied to synthesize 23-O-benzoylsilibinin

• (8b) in 55% yield [9]. Using benzoic acid with 6 equiv of Ph3P and 4 equiv of DIAD, silibinin was converted into ester 9b with a yield of 33% after purification (Table 1, entry 4). Again hydrolysis of 9b yielded hydnocarpin D (2). Being encouraged by the feasibility of using a common acid but still

Enantioselective additions of copper acetylides to cyclic iminium and oxocarbenium ions

• Jixin Liu,
• Srimoyee Dasgupta and
• Mary P. Watson

Beilstein J. Org. Chem. 2015, 11, 2696–2706, doi:10.3762/bjoc.11.290

• iminium ion 31 (Scheme 10) [32]. Subsequent alkynylation was accomplished using a CuI/N-Pinap catalyst to give N-benzylisoquinolines in exceptional yields and enantioselectivities. Notably, catalytic benzoic acid is necessary to achieve high yields. The authors hypothesize that this acid additive

Recent highlights in biosynthesis research using stable isotopes

• Jan Rinkel and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2015, 11, 2493–2508, doi:10.3762/bjoc.11.271

• agreement with the detection of (ring-2H5)benzoic acid in culture extracts from labeling experiments with (ring-2H5)Phe. This interconversion of two proteinogenic amino acids in the biosynthesis of an NRPS compound from secondary metabolism is unprecedented and its discovery was strongly supported by the

Synthesis of α,β-unsaturated esters via a chemo-enzymatic chain elongation approach by combining carboxylic acid reduction and Wittig reaction

• Yitao Duan,
• Peiyuan Yao,
• Yuncheng Du,
• Jinhui Feng,
• Qiaqing Wu and
• Dunming Zhu

Beilstein J. Org. Chem. 2015, 11, 2245–2251, doi:10.3762/bjoc.11.243

• toward benzoic acid (2a) (Supporting Information File 1, Table S1) were 1.75 ± 0.16 mM and 0.93 mM−1·s−1, respectively. They were lower than those for NiCAR [31], SrCAR [28] and MnCAR [33]. In order to explore the application potential of Mycobacterium CAR, its substrate specificity was examined with the

Recent advances in copper-catalyzed C–H bond amidation

• Jie-Ping Wan and
• Yanfeng Jing

Beilstein J. Org. Chem. 2015, 11, 2209–2222, doi:10.3762/bjoc.11.240

• functionalization with nitrogen nucleophiles, including amides, sulfonamides and primary arylamines. In addition, the oxazole-based DG could be easily deprotected to provide the corresponding benzoic acid 44 by heating in EtOH in the presence of KOH (Scheme 13). As another easily available N-containing aromatic

Molecular-oxygen-promoted Cu-catalyzed oxidative direct amidation of nonactivated carboxylic acids with azoles

• Wen Ding,
• Shaoyu Mai and
• Qiuling Song

Beilstein J. Org. Chem. 2015, 11, 2158–2165, doi:10.3762/bjoc.11.233

• ), inexpensive and readily available pyridine was employed as both the ligand and base in our case. Results and Discussion Our initial exploration commenced with benzoic acid (1) and benzimidazole (2) as the model substrates to investigate the copper-catalyzed oxidative direct amidation reaction (Table 1). The

• ) were mixed with benzoic acid under the standard conditions, compound 29 was obtained in 45% yield instead of the predicted amide 3 (Scheme 3a). Compound 3 was not detected in the reaction. Similarly, when 2-naphthoic acid (30) was used instead of benzoic acid (1), compound 31 was afforded in 56% yield

• reason to believe that the above proposed mechanism is plausible. In addition, pyridine N-oxide was applied to the benzoic acid standard conditions in the presence/absence of dioxygen. However, only a trace amount of the desired product 3 was ever detected, thus it was ruled out as a possible pathway

The facile construction of the phthalazin-1(2H)-one scaffold via copper-mediated C–H(sp²)/C–H(sp) coupling under mild conditions

• Wei Zhu,
• Bao Wang,
• Shengbin Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2015, 11, 1624–1631, doi:10.3762/bjoc.11.177

• on the use of prefunctionalized benzoic acid, such as phthalic anhydride or 2-formylbenzoic acid, as starting materials and suffer from low yields, poor regioselectivity and scope limitations [11][12]. Therefore, there is still a need for synthetic chemists to develop efficient and expedient routes

Preparative semiconductor photoredox catalysis: An emerging theme in organic synthesis

• David W. Manley and
• John C. Walton

Beilstein J. Org. Chem. 2015, 11, 1570–1582, doi:10.3762/bjoc.11.173

• further oxidation. SCPC oxidations that take place with varying success include toluene to benzaldehyde and benzoic acid [25], cyclohexane to cylohexanone [26], benzylic and allylic alcohols to carbonyl compounds [27] and alkene epoxidations [28]. Conventional syntheses of coumarins, which are important

Gold-catalyzed formation of pyrrolo- and indolo-oxazin-1-one derivatives: The key structure of some marine natural products

• Sultan Taskaya,
• Nurettin Menges and
• Metin Balci

Beilstein J. Org. Chem. 2015, 11, 897–905, doi:10.3762/bjoc.11.101

• acids has been reported in the literature to give the corresponding lactones [33][34][35][36][37][38][39][40]. For example, gold(I)-catalyzed reaction of 2-(phenylethynyl)benzoic acid (8) yielded the exo- and endo-dig cyclization products, lactones 9 and 10 in 62% yield in a ratio of 6:1 (Scheme 1) [41

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• ]. The 2-aminopyridine-1-oxide directing group was used in a rare example of a cobalt-catalyzed oxidative alkoxylation of arenes 66 and alkenes 67 to afford products 68 and 69 under mild contitions [69] (Scheme 14). The directing group can be removed to obtain the corresponding benzoic acid 71 from the

Synthesis of aromatic glycoconjugates. Building blocks for the construction of combinatorial glycopeptide libraries

• Markus Nörrlinger and
• Thomas Ziegler

Beilstein J. Org. Chem. 2014, 10, 2453–2460, doi:10.3762/bjoc.10.256

• as follows (Table 2). Both Fmoc-protected benzoic acid derivatives 7 and 9 (Scheme 1) were each condensed with each of the four malonylamidoglycosides 12a–d (Table 1) to afford eight intermediate tert-butyl esters 13 and 14 in 45–67% yield. For the condensation step between 7 and 9 with 12

• (Scheme 2). Treatment of 6 and 8 with a 2:1 mixture of formic acid and dichloromethane at room temperature for 38 h, as described for the preparation of building blocks 1 and 2 (see Table 2), afforded the benzoic acid derivatives 15 and 18 in 93% yield for each. Likewise, treatment of 5 and 8 with 20

• usefulness for the preparation of corresponding glycosylated or non-glycosylated dipeptides. The benzoic acid derived building blocks described here will be used in combination with previously described similar glycopeptoids based on asparaginic acid or PNA-like backbones for automated SPOT syntheses of

Visible light photoredox-catalyzed deoxygenation of alcohols

• Daniel Rackl,
• Viktor Kais,
• Peter Kreitmeier and
• Oliver Reiser

Beilstein J. Org. Chem. 2014, 10, 2157–2165, doi:10.3762/bjoc.10.223

• could be reduced again and defunctionalized materials were isolated in moderate to good yields (Table 3, entries 10 and 11). Bis(trifluoromethyl)benzoic acid 5 could easily be recovered (>90%) in an acid–base extraction step. Also bis(trifluoromethyl)benzoates of non-benzylic α-cyanohydrin 6a and α

• photochemical deoxygenation, 3,5-bis(trifluoromethyl)benzoic acid (5) is formed, which can be easily recovered in high yield and from which anhydride 9 can be regenerated as described above. Attempts to deoxygenate simple alkyl-substituted alcohols (primary, secondary and tertiary) were not successful; for

• (trifluoromethyl)benzoic acid can be recycled and reactivated under redox neutral conditions, and moreover, the in situ activation of alcohols with this auxiliary is possible we envision that an overall continuous process could be developed for the deoxygenation of alcohols by this protocol. That ultimately only

Multicomponent reactions in nucleoside chemistry

• Mariola Koszytkowska-Stawińska and
• Włodzimierz Buchowicz

Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179

• irradiation conditions with the substrates adsorbed onto Montmorillonite K-10 clay (Scheme 45) [122]. The formation of compounds 110 proceeded via: (a) N-acylation of aminosugar by the anthranilic acid derivative, and (b) N-acylation of the resulting amide at the aromatic amino group by benzoic acid (or 4

Olefin cross metathesis based de novo synthesis of a partially protected L-amicetose and a fully protected L-cinerulose derivative

• Bernd Schmidt and
• Sylvia Hauke

Beilstein J. Org. Chem. 2014, 10, 1023–1031, doi:10.3762/bjoc.10.102

• benzoylation in pyridine resulted exclusively in the formation of furan 10 (Table 2, entry 1). We reasoned that pyridine initiates an E/Z-isomerization of the enal through nucleophilic attack at the β-position, followed by lactol formation, benzoylation of the lactol and finally elimination of benzoic acid

• eventually obtained in high yields from benzoic acid using Steglich’s esterification [61] (Table 2, entry 3). With enal 9 in hands, selective hydrogenation of the C–C double bond had to be accomplished in the next step. Lipshutz’ modification [62] of Stryker’s reagent [63], which we had previously used

Staudinger ligation towards cyclodextrin dimers in aqueous/organic media. Synthesis, conformations and guest-encapsulation ability

• Malamatenia D. Manouilidou,
• Yannis G. Lazarou,
• Irene M. Mavridis and
• Konstantina Yannakopoulou

Beilstein J. Org. Chem. 2014, 10, 774–783, doi:10.3762/bjoc.10.73

• its X-ray structure solved in the case of reaction between benzyl azide and 2-(diphenylphosphanyl)benzoic acid methyl ester [7]. The advantages of the Staudinger ligation and its “traceless” variant [6][8] are the employment of the azido group, a moiety orthogonal to naturally existing functional

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

• that the lower electrophilicity of arylimines and the possible enamide conjugation could account for this. Furthermore, it was shown that the pKa of the carboxylic acid significantly influenced the reaction rates, in which TFA gave the best results (2 days vs. 5 days for benzoic acid). No

• orthogonally protected carbohydrate-derived azido-acetal and trimethylphosphine yielded the necessary cyclic imine, which then was exposed to benzoic acid and different isocyanides. The resulting Ugi-bisamides 163 were obtained in moderate to good yields (22–78%), in which the more sterically demanding

Preparation of new alkyne-modified ansamitocins by mutasynthesis

• Kirsten Harmrolfs,
• Lena Mancuso,
• Binia Drung,
• Florenz Sasse and
• Andreas Kirschning

Beilstein J. Org. Chem. 2014, 10, 535–543, doi:10.3762/bjoc.10.49

• polyketide synthase in A. pretiosum and thus no formation of new ansamitocin derivatives was encountered in these cases. In contrast, benzoic acid 11 provided Br-F-ansamitocin derivatives 21a–d after being fed to a growing culture of the mutant strain as judged by HRMS (Scheme 4). The retention times in LC

• )benzoic acid 12 to cultures of the AHBA(−)-mutant of A. pretiosum yielded six new alkynyl-modified ansamitocin derivatives 23a–f in yields in the lower mg/L range (Scheme 6). Among them, the major compound 23f was obtained in 0.34% yield based on compound 12, furnishing enough mutasynthetic material (15

• MS spectra. Derivatives 23a, 23b, 23d, 23e and 24a, 24e were detected only by HRMS–MS analysis of the crude extract. Mutasynthetic experiments with vinyl(amino)benzoic acid 15 supposedly provided ansamitocin derivative 25 as judged by HRMS–MS analysis of the crude extract (Scheme 7). However, yields