Synthesis of 9-arylalkynyl- and 9-aryl-substituted benzo[b]quinolizinium derivatives by Palladium-mediated cross-coupling reactions

• Siva Sankar Murthy Bandaru,
• Darinka Dzubiel,
• Heiko Ihmels,
• Mohebodin Karbasiyoun,
• Mohamed M. A. Mahmoud and
• Carola Schulzke

Beilstein J. Org. Chem. 2018, 14, 1871–1884, doi:10.3762/bjoc.14.161

• engage in π···π donor–acceptor attractions with the pyridinium moiety (outer most ring of the tricyclic moiety) and the two positively charged nitrogen atoms are per se much further apart due to the larger intramolecular separation between the intermolecularly interacting π-systems. In addition, the

Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepine derivatives by [3⁺ + 2]-cycloaddition/rearrangement reactions

• Lin-bo Luan,
• Zi-jie Song,
• Zhi-ming Li and
• Quan-rui Wang

Beilstein J. Org. Chem. 2018, 14, 1826–1833, doi:10.3762/bjoc.14.155

• Lin-bo Luan Zi-jie Song Zhi-ming Li Quan-rui Wang Department of Chemistry, Fudan University, 2005 Songhu Road, Fudan University, Shanghai 200438, People’s Republic of China 10.3762/bjoc.14.155 Abstract Two new series of tricyclic heterocycles, namely 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d

• furnishing the tricyclic 1,2,4-triazole-fused 1,4-benzodiazepines. Keywords: 1,4-benzodiazepine (BDZ); cyclization; hydrazones; oxidation; rearrangement; Introduction Heterocyclic compounds comprising a 1,4-benzodiazepine (BDZ) ring have been a topic of continued interest as they exhibit a wide spectrum of

• , we wish to describe the synthesis of unprecedented tricyclic heterocycles, i.e., 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepinium salts 10 and the related neutral free base derivatives 13 via the cationic [3+ + 2]-cycloaddition/rearrangement reactions using the bicyclic 4-acetoxy-4-azo

Synthesis of spirocyclic scaffolds using hypervalent iodine reagents

• Fateh V. Singh,
• Priyanka B. Kole,
• Saeesh R. Mangaonkar and
• Samata E. Shetgaonkar

Beilstein J. Org. Chem. 2018, 14, 1778–1805, doi:10.3762/bjoc.14.152

• ). Furthermore, spirolactam was used as intermediate in the synthesis of tricyclic compound 43 possessing a similar structure like that of the naturally occurring heterocyclic compound FR901483 [82]. Wardrop and co-workers [83] developed a new method for the preparation of 1-azaspiranes 47 by treatment of α- and

• ) in presence of 3.0 equivalents of TFA as an additive in dichloromethane (Scheme 17). The fused tricyclic compound 53 was obtained as major product in 55% yield along with the spiro compound 54 as a minor product in 8% yield. In 2009, Zhang and co-workers [89] reported an efficient method for the

• ). Furthermore, the absolute configuration of 88 was assigned by its single crystal X-ray analysis. 3.3. Application of spirolactams in natural product synthesis In 2001, Ciufolini and co-workers [103] employed PIDA (15) as an electrophile during the synthesis of naturally occurring tricyclic azaspirane

Metal-free formal synthesis of phenoxazine

• Gabriella Kervefors,
• Antonia Becker,
• Chandan Dey and
• Berit Olofsson

Beilstein J. Org. Chem. 2018, 14, 1491–1497, doi:10.3762/bjoc.14.126

• , unusually stable iodine(III) intermediate in the O-arylation was observed by NMR and could be converted to the product upon longer reaction time. Keywords: arylation; cyclization; diaryl ether; diaryliodonium salt; phenol; Introduction Phenoxazine (1) is a tricyclic compound consisting of an oxazine ring

A survey of chiral hypervalent iodine reagents in asymmetric synthesis

• Soumen Ghosh,
• Suman Pradhan and
• Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

• spirocyclization of naphthol carboxylic acid [34]. Later Birman et al. reported a new variation of a chiral I(V) reagent, namely 2-(o-iodoxyphenyl)oxazoline derivative 28 [35]. The reagent was applied to an asymmetric [4 + 2] Diels–Alder dimerization of phenolic derivatives 29 to construct tricyclic derivatives 30

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• ]. Transformation of adduct 31 to 11 starts with the synthesis of the stable cyclopropanoid tricyclic 32 from the reaction of the 7-oxabenzonorbornadiene 31 with dichlorocarbene, generated by the phase-transfer method. The thermolysis of dichloride 32 in nitrobenzene at 165 °C resulted in the formation of ring

• anhydride (204) to give a tricyclic adduct 207 (in 90% yield) (Scheme 35) [141][142]. Later, Middlemiss’ group also used dienophiles such as maleic anhydride (204), N-methylmaleimide (205), and N-phenylmaleimide (206) to give endo-adducts 207–209 [148]. Furthermore, these ethenobenzocycloheptenones 207–209

Iodine(III)-mediated halogenations of acyclic monoterpenoids

• Laure Peilleron,
• Tatyana D. Grayfer,
• Joëlle Dubois,
• Robert H. Dodd and
• Kevin Cariou

Beilstein J. Org. Chem. 2018, 14, 1103–1111, doi:10.3762/bjoc.14.96

• bromocarbocyclization of aryl-geranyl derivatives using a combination of iodine(III) oxidant and a bromide source. In this fashion, the reaction of homogeranylbenzene with bis(tert-butylcarbonyloxy)iodobenzene and triethylsilyl bromide, followed by acidic treatment led to a tricyclic brominated adduct (Scheme 1

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

Continuous-flow retro-Diels–Alder reaction: an efficient method for the preparation of pyrimidinone derivatives

• Imane Nekkaa,
• Márta Palkó,
• István M. Mándity and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2018, 14, 318–324, doi:10.3762/bjoc.14.20

• the developed CF technology is superior to existing conventional batch technologies. Results and Discussion The starting materials, i.e., fused tricyclic or tetracyclic pyrimidinones 1–8 have been previously prepared by literature methods [26][45][46][47][48][49][50]. Cyclization of the corresponding

• di-exo- or di-endo-amino acids or esters with ethyl p-chlorobenzimidate resulted in tricyclic pyrimidinones 1, 2a and 2b [26][45][46][47][48][49]. Methanopyrrolo-, methanopyrido- and methanoazepino[2,1-b]quinazolinones 3–6 were prepared by ring enlargement of di-exo-norbornene-fused azetidinones with

• . The residence time was set by the use of coils with different lengths. The pressure and flow rate of the reactions were kept at constant values of 10 bars and 0.5 mL min−1, respectively. The full reaction parameter optimization is shown only for compound 1 in Table 1. The tricyclic di-exo-2-(4

Novel amide-functionalized chloramphenicol base bifunctional organocatalysts for enantioselective alcoholysis of meso-cyclic anhydrides

• Lingjun Xu,
• Shuwen Han,
• Linjie Yan,
• Haifeng Wang,
• Haihui Peng and
• Fener Chen

Beilstein J. Org. Chem. 2018, 14, 309–317, doi:10.3762/bjoc.14.19

• conveniently converted into the corresponding monoester products in high yields and enantioselectivities. Notably, bicyclic anhydrides (Table 2, entries 1 and 2) and tricyclic anhydrides (Table 2, entries 3 and 4) were more reactive than mono-cyclic anhydrides (Table 2, entries 5–12). In the case of mono

Fluorogenic PNA probes

• Tirayut Vilaivan

Beilstein J. Org. Chem. 2018, 14, 253–281, doi:10.3762/bjoc.14.17

• was accompanied by fluorescence quenching, and Vg-modified aegPNA has been used to probe the interaction between RNA quadruplexes and PNA [181]. Another example of a nucleobase with extended conjugation that has been incorporated into PNA is 1,3-diaza-2-oxophenothiazine (tC), which is a tricyclic

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

Gram-scale preparation of negative-type liquid crystals with a CF₂CF₂-carbocycle unit via an improved short-step synthetic protocol

• Tatsuya Kumon,
• Shohei Hashishita,
• Takumi Kida,
• Shigeyuki Yamada,
• Takashi Ishihara and
• Tsutomu Konno

Beilstein J. Org. Chem. 2018, 14, 148–154, doi:10.3762/bjoc.14.10

• discovery of fluorinated liquid-crystalline (LC) molecules [10][11] led to the rational molecular design and synthesis of a family of novel fluorinated LC molecules that possess large negative dielectric anisotropy (Δε). In fact, as shown in Figure 1, tricyclic molecules containing a CF2CF2 carbocycle, e.g

• subsequently synthesized 1b, 1c, 2b, and 2c using the corresponding Grignard reagents, e.g., (4-n-PrC6H4)C6H4MgBr or 4-(trans-4-n-Pr-c-C6H10)C6H4MgBr, instead of 4-n-PrC6H4MgBr. As shown in Table 1, all reactions proceeded well to afford the corresponding adducts in acceptable to excellent yields. Tricyclic

Fluorescent nucleobase analogues for base–base FRET in nucleic acids: synthesis, photophysics and applications

• Mattias Bood,
• Sangamesh Sarangamath,
• Moa S. Wranne,
• Morten Grøtli and
• L. Marcus Wilhelmsson

Beilstein J. Org. Chem. 2018, 14, 114–129, doi:10.3762/bjoc.14.7

• . Keywords: B-to-Z-DNA transition; fluorescent base analogues; FRET; netropsin; nucleic acid structure and dynamics; quadracyclic adenines; tricyclic cytosines; Z-DNA; Review Introduction The importance of nucleic acid structure and dynamics in the understanding of vital processes in living organisms has

• probe BFdG, 3-MI, 2PyG, as well as the emissive RNA analogue thG [23][26][27][28]. Some notable pyrimidine analogues include our tricyclic analogues tC and tCO [29][30][31], pyrrolo-dC [32] and its derivatives [33] as well as thU, thC [23] and DMAC [34]. Apart from tC, tCO, qAN1 and thG, FBAs have not

• developing the family of fluorescent base analogues known as the tricyclic cytosines (tC) [14][29][30][31][35][36][37][38]. The aromatic core of tC was first prepared by Roth et al. in 1963 as part of a study to obtain pharmacologically active compounds structurally similar to phenothiazines [39]. Compound 1

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

• regioselectively form this instead of 3a and 4. This tricyclic backbone can be found in compounds that possess a wide range of medicinal properties including those with antimalarial [74], anticancer [75][76], antiallergic [77][78], antibacterial [79], and antimicrobial properties [80][81]. In addition, they have

• attacks at both carbonyl groups to form benzo[4,5]thiazolo[3,2-a]pyrimidin-4-ones. The scope of these regiodivergent protocols was demonstrated with 19 examples of tricyclic benzo[d]imidazo[2,1-b]thiazoles and 27 examples of tricyclic and tetracyclic benzo[4,5]thiazolo[3,2-a]pyrimidin-4-ones. Experimental

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

• Anna Kuźnik,
• Roman Mazurkiewicz and
• Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

• ]. The use of pyrocatechol or pyrogallol as reagents in reactions with the analogous mechanism resulted in the formation of mono-, di-, and tricyclic reaction products of phenol derivatives with one or two vinylphosphonium salt molecules (Scheme 62 and Scheme 63) [75]. In a similar reaction with 2

• nucleophilic displacement of the triphenylphosphonium group in intermediate α,β-di(alkoxycarbonyl)vinylphosphonium salts. Synthesis of 6-formylcoumarin derivatives and their application in the synthesis of dyads. Synthesis of di- and tricyclic coumarin derivatives in the reaction of pyrocatechol with two

• vinylphosphonium salt molecules. Synthesis of mono-, di-, and tricyclic derivatives in the reaction of pyrogallol with one or two vinylphosphonium salt molecules. Synthesis of 1,4-benzoxazine derivative by nucleophilic displacement of the triphenylphosphonium group in intermediate α,β-di(methoxycarbonyl

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• distance is 3.437(4) Å. Consequently, π–π interactions must be considered for this structure [51][52]. Bond lengths and angles of the reported crystal structures 4b, 5, and 6 are in the expected range. The tricyclic 1H-benzo[f]isoindole-1,3(2H)-dionyl moiety in 4b, 5 and the corresponding 3-imino-1-oxo-2,3

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

• Yaroslav D. Boyko,
• Valentin S. Dorokhov,
• Alexey Yu. Sukhorukov and
• Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

• intermediate 45, which was subjected to Wittig olefination. Subsequent aza-Sakurai cyclization of intermediate 46 provided tricyclic derivative 47 as a single stereoisomer, which was then transformed into target myrioneurinol by standard operations. Addition of organometallic reagents to conjugated

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• ][30]. Alternative approaches by utilizing chiral backbones like, e.g., tartaric acid, biphenyls, or tricyclic ammonium salts were also heavily investigated [31][32][33][34][35], thus leading to an enormous recent progress in the field with respect to catalyst design and the development of new

Synthesis of alkynyl-substituted camphor derivatives and their use in the preparation of paclitaxel-related compounds

• M. Fernanda N. N. Carvalho,
• Rudolf Herrmann and
• Gabriele Wagner

Beilstein J. Org. Chem. 2017, 13, 1230–1238, doi:10.3762/bjoc.13.122

• the C–C bond between the atoms bearing the OH and NH groups (ring enlargement). The result is an isomerisation of 4a and 4b to form tricyclic compounds 7 containing a nine-membered carbocyclic ring (Scheme 3a) [27]. Isomerisations are the best examples for a perfect “atom economy” [28][29][30] since

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

• reagent. The reaction temperature and residence time are 80 °C and 3.5 min, respectively. This product further undergoes a coupling reaction in a packed column containing polymer-supported [bis(trifluoroacetoxy)iodo]benzene (PS-PIFA), which yields a seven-membered tricyclic intermediate with 50% yield

• . The tricyclic intermediate is further mixed with MeOH and water (4:1) and passed through a packed column containing a polymer-supported base at 35 °C. The target compound (±)-oxomaritidine was obtained in 40% yield. The block diagram of different steps performed in this synthesis is shown in Figure 6A

• (trifluoroacetoxy)iodo]benzene as packing material. The control strategy for the packed bed reactor will be similar as discussed earlier. The process stream containing the tricyclic intermediate can be cooled to 35 °C by mixing a cold stream of MeOH/water at the desired mole ratio using a ratio controller. The

Opportunities and challenges for the sustainable production of structurally complex diterpenoids in recombinant microbial systems

• Katarina Kemper,
• Max Hirte,
• Markus Reinbold,
• Monika Fuchs and
• Thomas Brück

Beilstein J. Org. Chem. 2017, 13, 845–854, doi:10.3762/bjoc.13.85

• naturally leads to the formation of tricyclic taxadiene [56] was achieved by exchanging a valin in position 584 with methionine. The resulting product was identified as a bicyclic diterpene of the verticillene type [51] (Scheme 2). A single residue switch in position 753 (W753H) presumably causes premature

• side: The natural product of wild-type cyclooctat-9-en-7-ol-synthase (CotB2) is a tricyclic diterpene whereas mutations in positions 107 and 288 yield in monocyclic cembrene A and bicyclic 3,7,18-dolabellatriene [57]. Changing the main product specificity of taxadiene synthase from Taxus brevifolia

Phosphazene-catalyzed desymmetrization of cyclohexadienones by dithiane addition

• Matthew A. Horwitz,
• Elisabetta Massolo and
• Jeffrey S. Johnson

Beilstein J. Org. Chem. 2017, 13, 762–767, doi:10.3762/bjoc.13.75

• nucleophilic group were appended to the para-quinol, it would be possible to construct a 5–6–5 fused ring system. Indeed, when R = CH2CH2NHBoc (1f), the desired tricyclic product 2f was obtained. In all cases only a single diastereomer was observed. In a substrate where a β-methyl group is present on the

Inclusion complexes of β-cyclodextrin with tricyclic drugs: an X-ray diffraction, NMR and molecular dynamics study

• Franca Castiglione,
• Fabio Ganazzoli,
• Luciana Malpezzi,
• Andrea Mele,
• Walter Panzeri and
• Giuseppina Raffaini

Beilstein J. Org. Chem. 2017, 13, 714–719, doi:10.3762/bjoc.13.70

• 7, 20131 Milano, Italy 10.3762/bjoc.13.70 Abstract Tricyclic fused-ring cyclobenzaprine (1) and amitriptyline (2) form 1:1 inclusion complexes with β-cyclodextrin (β-CD) in the solid state and in water solution. Rotating frame NOE experiments (ROESY) showed the same geometry of inclusion for both 1

• explicit water to study the inclusion complexes of two tricyclic aromatic molecules – cyclobenzaprine (1) and amitriptyline (2, Figure 1) – with β-cyclodextrin (β-CD). Previous work already considered certain aspects of the interaction of 2 with β-CD [3][4][5][6][7][8], but no full characterization of the

• any disorder: this finding is largely predictable for the rigid tricyclic moiety of 1 but it is remarkable in 2. Indeed, literature data on isolated amitriptyline point out that the fused ring system of 2 shows conformational transitions [10], especially those involving the torsion about the C9–C10

Posttranslational isoprenylation of tryptophan in bacteria

• Masahiro Okada,
• Tomotoshi Sugita and
• Ikuro Abe

Beilstein J. Org. Chem. 2017, 13, 338–346, doi:10.3762/bjoc.13.37

• tricyclic skeleton that bears a newly formed pyrrolidine, similar to proline. The post-translational dimethylallylation of two tryptophan residues of a cyclic peptide, kawaguchipeptin A, from cyanobacteria has also been reported. Interestingly, the modified tryptophan residues of kawaguchipeptin A have the

• either a geranyl or farnesyl group at the gamma position to form tricyclic skeleton that bears a newly formed pyrrolidine, which is similar to proline (Figure 3A) [26][27][28]. The posttranslational modification of ComX pheromones with an isoprenoid plays an essential role for specific quorum sensing

• configurations of the tricyclic core scaffold were essential and more critical for its pheromonal activity than the amino acid sequence of the ComXRO-E-2 pheromone [29][30][31][32]. In addition, a previous study using a conditioned medium with Bacillus strains suggested that the chemical structure of the