Different reactivity of phosphorylallenes under the action of Brønsted or Lewis acids: a crucial role of involvement of the P=O group in intra- or intermolecular interactions at the formation of cationic intermediates

• Stanislav V. Lozovskiy,
• Alexander Yu. Ivanov and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2019, 15, 1491–1504, doi:10.3762/bjoc.15.151

• able to measure its 1H NMR spectrum in D2O at elevated temperature (80 °C, see Supporting Information File 1). Taking into account the stability of the P–N bond against hydrolysis, we conducted reactions of the cations A, B, and F–H with morpholine (Scheme 3). Amides 6a,b were isolated as products of

• these reactions in excellent yields. The plausible reaction mechanism includes at the first stage nucleophilic attack of morpholine onto the phosphorus cationic center that gives cation I, which is transformed into species J. Hydrolysis of the latter leads to cation K and then finally to amides 6a,b. We

• ) gave cations A and B, respectively. The interaction of these species with morpholine followed by hydrolysis furnished the target amides 6a,b in total yields of 60–90% (see procedures in Supporting Information File 1). It should be noted that allene 1d bearing no alkyl groups and monoalkylated allene 1c

Remarkable effect of alkynyl substituents on the fluorescence properties of a BN-phenanthrene

• Alberto Abengózar,
• David Sucunza,
• Patricia García-García and
• Juan J. Vaquero

Beilstein J. Org. Chem. 2019, 15, 1257–1261, doi:10.3762/bjoc.15.122

• , whose emission maxima are slightly red-shifted (395 and 392 nm vs 356 nm for unsubstituted 1a). In contrast, 7-alkynyl-substituted BN-phenanthrenes 1e and 1f show emission maxima analogous to that of the parent BN-phenanthrene 1a. With regard to the fluorescence quantum yield, phenyl and morpholine

Multicomponent reactions (MCRs): a useful access to the synthesis of benzo-fused γ-lactams

• Edorta Martínez de Marigorta,
• Jesús M. de Los Santos,
• Ana M. Ochoa de Retana,
• Javier Vicario and
• Francisco Palacios

Beilstein J. Org. Chem. 2019, 15, 1065–1085, doi:10.3762/bjoc.15.104

• most of the cases, the Z-isomer as the sole or main product, while tert-butyl derivatives gave the E-isomer selectively. On the secondary amine side, morpholine, piperidine, pyrrolidine and dibutylamine all rendered the reaction efficiently. A plausible explanation for the mechanism of this

Diaminoterephthalate–α-lipoic acid conjugates with fluorinated residues

• Leon Buschbeck,
• Aleksandra Markovic,
• Gunther Wittstock and
• Jens Christoffers

Beilstein J. Org. Chem. 2019, 15, 981–991, doi:10.3762/bjoc.15.96

• trifluoromethylated benzaldehyde was accomplished as described for compound 2 and furnished product 6 in 91% yield. The Alloc-protecting group was then cleaved (95% yield of product 8) in a palladium-catalyzed allylic substitution reaction with morpholine as a scavenger of the allylic cation [45][46]. Finally, the

• -(trifluoromethyl)benzylamino]terephthalate (8): Under exclusion of air and moisture, morpholine (1.17 mmol, 102 mg, 5.0 equiv) was added to a solution of carbamate 6 (0.234 mmol, 129 mg, 1.0 equiv) in abs. CH2Cl2 (3 mL). The mixture was degassed (three cycles of freeze, pump and thaw). Then Pd(PPh3)4 (12 µmol, 14

Hoveyda–Grubbs catalysts with an N→Ru coordinate bond in a six-membered ring. Synthesis of stable, industrially scalable, highly efficient ruthenium metathesis catalysts and 2-vinylbenzylamine ligands as their precursors

• Kirill B. Polyanskii,
• Kseniia A. Alekseeva,
• Pavel V. Raspertov,
• Pavel A. Kumandin,
• Eugeniya V. Nikitina,
• Atash V. Gurbanov and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2019, 15, 769–779, doi:10.3762/bjoc.15.73

• concluded that dichloromethane is the best solvent for this reaction. At 40 °C, concentrations from 1.0 to 0.1 mol % of the morpholine-based complex 11d showed the best catalytic activity by providing styrene in 91–97% yields (entries 12 and 13 of Table 3). The somewhat less sterically loaded N,N-diethyl

An efficient and concise access to 2-amino-4H-benzothiopyran-4-one derivatives

• Peng Li,
• Yongqi Wu,
• Tingting Zhang,
• Chen Ma,
• Ziyun Lin,
• Gang Li and
• Haihong Huang

Beilstein J. Org. Chem. 2019, 15, 703–709, doi:10.3762/bjoc.15.65

• strong nucleophilicity of piperazine and morpholine, the substrates with electron-donating/withdrawing and halogen groups smoothly delivered the N-substituted 2-aminobenzothiopyranones 4j–o and 4t,u in good to excellent yields. Specifically, the substrates containing a strong electron-withdrawing group

Sigmatropic rearrangements of cyclopropenylcarbinol derivatives. Access to diversely substituted alkylidenecyclopropanes

• Guillaume Ernouf,
• Jean-Louis Brayer,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2019, 15, 333–350, doi:10.3762/bjoc.15.29

• presence of triethylamine under mild conditions (CH2Cl2, −78 °C) [55] and the in situ-generated cyanate 27 underwent a sigmatropic rearrangement into the corresponding isocyanate 28. The formation of this reactive isocyanate intermediate was ascertained by the addition of morpholine which enabled the

A general and atom-efficient continuous-flow approach to prepare amines, amides and imines via reactive N-chloramines

• Katherine E. Jolley,
• Michael R. Chapman and
• A. John Blacker

Beilstein J. Org. Chem. 2018, 14, 2220–2228, doi:10.3762/bjoc.14.196

• equivalents of aldehyde 17 led to 30% product formation (Table 3, entry 6). Notably, other oxidants such as H2O2 and NaOCl failed to produce any amide product. Likewise, attempts to couple morpholine in place of its N-chloro derivative reached only 19% conversion. Following the investigation of the batch

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

Syn-selective silicon Mukaiyama-type aldol reactions of (pentafluoro-λ⁶-sulfanyl)acetic acid esters with aldehydes

• Anna-Lena Dreier,
• Andrej V. Matsnev,
• Joseph S. Thrasher and
• Günter Haufe

Beilstein J. Org. Chem. 2018, 14, 373–380, doi:10.3762/bjoc.14.25

• -substituted acetamides into aldol additions with the intension of applying amides in Evans-type substrate directed asymmetric C–C-bond forming reactions. Therefore, 2-(pentafluoro-λ6-sulfanyl)acetic morpholide (8) was prepared by reaction of SF5-CH2C(O)Cl (7) [36][37] with morpholine (Scheme 5). According to

• two multiplets of the morpholine ring for four protons each at δ = 3.37 ppm and δ = 3.28 ppm, one can reason the formation of an aldol addition product 9. This assignment is supported by a multiplet for one axial fluorine atom at δ = 75.39 ppm (J = 147 Hz) and a doublet (of multiplets) for four

Stereochemical outcomes of C–F activation reactions of benzyl fluoride

• Neil S. Keddie,
• Pier Alexandre Champagne,
• Justine Desroches,
• Jean-François Paquin and
• David O'Hagan

Beilstein J. Org. Chem. 2018, 14, 106–113, doi:10.3762/bjoc.14.6

• corresponding benzyl fluoride (1) using a modification of Bio’s method [13][14] to promote the SN2 reaction exclusively, using TMS-morpholine and DAST, in moderate yield (51%) and high ee (94%). The isotopically enriched [2H1]-benzyl fluoride ((R)-1, 95% ee) was then subjected to a range of C–F activation

• that some nucleophiles (such as N-methylbenzylamine and morpholine [not shown]) were unsuitable for this study, as the resulting products 7 could not be resolved in the 2H NMR with PBLG assay. Two different activator systems were investigated for the nucleophilic substitution of 1: a mixture of water

Homologated amino acids with three vicinal fluorines positioned along the backbone: development of a stereoselective synthesis

• Raju Cheerlavancha,
• Ahmed Ahmed,
• Yun Cheuk Leung,
• Aggie Lawer,
• Qing-Quan Liu,
• Marina Cagnes,
• Hee-Chan Jang,
• Xiang-Guo Hu and
• Luke Hunter

Beilstein J. Org. Chem. 2017, 13, 2316–2325, doi:10.3762/bjoc.13.228

• it was found that the inclusion of the additive TMS-morpholine [36][37] was also required to ensure a high diastereoisomeric excess of 38a. The epoxide 38a was then ring-opened using Et3N·3HF to deliver the difluorodiol 39a as a mixture of regioisomers. This mixture subsequently converged during the

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

• and ester groups. The reactions of E-1 with morpholine performed in the presence of equimolar amounts of strained 1-azabicyclo[1.1.0]butanes 55 afforded enamines 56 containing both amine units [58] (Scheme 19). Their structures evidence that the first reaction step is the Michael-type reaction of 55

• leading to a zwitterionic intermediate 57, which is trapped by morpholine to give the adduct 58. The latter eliminates HCN and converts to enamine 56. The postulated pathway was supported by a similar experiment, in which methanol replaced morpholine as a trapping reagent [58][59]. An interesting

Preparation of imidazo[1,2-a]-N-heterocyclic derivatives with gem-difluorinated side chains

• Layal Hariss,
• Kamal Bou Hadir,
• Mirvat El-Masri,
• Thierry Roisnel,
• René Grée and
• Ali Hachem

Beilstein J. Org. Chem. 2017, 13, 2115–2121, doi:10.3762/bjoc.13.208

• , respectively. On the other hand, two nucleophilic substitution reactions using phenol and morpholine gave the expected heterocycles 10 and 11 in 73% and 23% yields, respectively. Conclusion In summary, we developed a short and completely regioselective method for the synthesis of imidazo[1,2-a]-N-heterocycles

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

• 4-(benzenesulfinyl)morpholine (BSM)/Tf2O [53]. The combination of BSP/Tf2O [19][49] has been utilized as the promoter for iterative oligosaccharide synthesis including oligoglucosamine library [20], oligomannan [54] and Lewisa trisaccharide [55]. During their synthesis, van der Marel and co-workers

Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

• the sole products. Contrastingly, in the solution of acetonitrile imines of benzaldehyde and amines were formed preferably. Different aromatic or heteroaromatic aldehydes including thiophene carboxaldehyde, pyridine carboxaldehyde and cyclohexyl carboxaldehyde as well as various amines like morpholine

Mechanochemical synthesis of thioureas, ureas and guanidines

• Vjekoslav Štrukil

Beilstein J. Org. Chem. 2017, 13, 1828–1849, doi:10.3762/bjoc.13.178

• -type amine–isothiocyanate coupling reaction (Scheme 4). In the case of secondary amines (piperidine, morpholine and thiomorpholine) and sterically hindered amines (2,4- and 2,6-dimethylanilines), ball milling again resulted in ≥99% yields in 10 minutes, except for the reactions involving 4

Substitution of fluorine in M[C₆F₅BF₃] with organolithium compounds: distinctions between O- and N-nucleophiles

• Anton Yu. Shabalin,
• Nicolay Yu. Adonin and
• Vadim V. Bardin

Beilstein J. Org. Chem. 2017, 13, 703–713, doi:10.3762/bjoc.13.69

• benzimidazolyl) with 74–93% isolated yield. In contrast, sodium morpholinide and sodium diethylamide did not react with K[C6F5BF3] under the same conditions. The attempted preparation of K[4-R2NC6F4BF3] (R2N = morpholinyl, Et2N) using an excess of dialkylamine as well as morpholine and K2CO3 leads to C6F5H and

Effect of the ortho-hydroxy group of salicylaldehyde in the A³ coupling reaction: A metal-catalyst-free synthesis of propargylamine

• Sujit Ghosh,
• Kinkar Biswas,
• Suchandra Bhattacharya,
• Pranab Ghosh and
• Basudeb Basu

Beilstein J. Org. Chem. 2017, 13, 552–557, doi:10.3762/bjoc.13.53

• in developing new organic reaction methodologies as well as to synthesize propargylamine, we performed one reaction of salicylaldehyde, morpholine and phenylacetylene at 80 °C in the presence of a Cu(I) dithiane-based complex as the catalyst that gave rise to the formation of 3a in good yield (89

• achieved in the first two solvents (85–88%), the use of ethanol resulted in a low yield (47%). Thus the A3 coupling of salicylaldehyde, phenylacetylene and morpholine can be achieved under solvent-free conditions as well as in solvents like toluene or acetonitrile with the formation of the coupled product

• in 85–90% isolated yields. We also conducted similar reactions with cyclohexylamine and benzylamine instead of morpholine. In both cases, we ended up with the formation of corresponding imines (Table 1, entries 12 and 13). After the successful optimization, further extension of the reaction protocol

Synthesis of spiro[isoindole-1,5’-isoxazolidin]-3(2H)-ones as potential inhibitors of the MDM2-p53 interaction

• Salvatore V. Giofrè,
• Santa Cirmi,
• Raffaella Mancuso,
• Francesco Nicolò,
• Giuseppe Lanza,
• Laura Legnani,
• Agata Campisi,
• Maria A. Chiacchio,
• Michele Navarra,
• Bartolo Gabriele and
• Roberto Romeo

Beilstein J. Org. Chem. 2016, 12, 2793–2807, doi:10.3762/bjoc.12.278

• isomeric mixture, followed by filtration. (1RS,4'RS)-2,2'-Dibenzyl-4'-(morpholine-4-carbonyl)spiro[isoindoline-1,5'-isoxazolidin]-3-one (6a): White solid; mp 197–199 °C (Yield: 71 mg, 51%); IR (KBr) νmax: 1685, 1638 cm−1; 1H NMR (500 MHz, CDCl3) δ 7.82–7.78 (m, 1H), 7.62–7.47 (m, 5H), 7.43 (d, J = 7.1 Hz

• , 484.2262. (1RS,4'SR)-2,2'-Dibenzyl-4'-(morpholine-4-carbonyl)spiro[isoindoline-1,5'-isoxazolidin]-3-one (7a): White crystals, mp 185–187 °C (Yield: 12 mg, 9%); IR (KBr) νmax: 1680, 1642 cm−1; 1H NMR (500 MHz, CDCl3) δ 7.80 (d, J = 6.7 Hz, 1H), 7.62–7.46 (m, 4H), 7.45–7.20 (m, 10H), 5.05 (d, J = 11.6 Hz, 1H

• , 53.9, 46.1, 46.0, 40.6, 31.4, 25.9, 23.8, 20.7, 13.9; HRMS–ESI (m/z): [M + H]+ calcd for C26H32N3O3, 434.2444; found, 434.2471. (1RS,4'RS)-2'-Benzyl-2-butyl-4'-(morpholine-4-carbonyl)spiro[isoindoline-1,5'-isoxazolidin]-3-one (6c): White solid, mp 122–124 °C (Yield: 54 mg, 38%); IR (KBr) νmax: 1687

Construction of bis-, tris- and tetrahydrazones by addition of azoalkenes to amines and ammonia

• Artem N. Semakin,
• Aleksandr O. Kokuev,
• Yulia V. Nelyubina,
• Alexey Yu. Sukhorukov,
• Petr A. Zhmurov,
• Sema L. Ioffe and
• Vladimir A. Tartakovsky

Beilstein J. Org. Chem. 2016, 12, 2471–2477, doi:10.3762/bjoc.12.241

• ). Similarly, the reaction with a secondary amine (morpholine) according to this procedure provided the monoalkylated adduct 6 in good yield. Importantly, secondary polyamines could be exhaustively alkylated with chloroacetone hydrazone 1a demonstrating the efficiency of our approach for the synthesis of

Microwave-assisted synthesis of (aminomethylene)bisphosphine oxides and (aminomethylene)bisphosphonates by a three-component condensation

• Erika Bálint,
• Ádám Tajti,
• Anna Dzielak,
• Gerhard Hägele and
• György Keglevich

Beilstein J. Org. Chem. 2016, 12, 1493–1502, doi:10.3762/bjoc.12.146

• column chromatography, the new amino-methylenebisphosphine oxides 1a–d were obtained in yields of 72–82% (Table 1, entries 1–4). The condensation of simple secondary amines (diethyl-, dibutyl-, N-butylmethyl-, N-cyclohexylmethyl-, N-benzylmethylamine, N-methylaniline and morpholine) was also investigated

Antibacterial structure–activity relationship studies of several tricyclic sulfur-containing flavonoids

• Lucian G. Bahrin,
• Henning Hopf,
• Peter G. Jones,
• Laura G. Sarbu,
• Cornelia Babii,
• Alina C. Mihai,
• Marius Stefan and
• Lucian M. Birsa

Beilstein J. Org. Chem. 2016, 12, 1065–1071, doi:10.3762/bjoc.12.100

• , synthesized by reacting morpholine with halogenated benzaldehydes [21][22], are collected in Table 1. The individual substitution patterns and yields for flavonoids 4a–m and 5a–m are presented in Table 2. The reaction between brominated and iodinated phenacyl carbodithioates 2a–f and halogenated aminals 3a–e

Opportunities and challenges for direct C–H functionalization of piperazines

• Zhishi Ye,
• Kristen E. Gettys and
• Mingji Dai

Beilstein J. Org. Chem. 2016, 12, 702–715, doi:10.3762/bjoc.12.70

• -amine radical followed by trapping with acrylate, to functionalize the α-position of amines [68]. The strategy works for morpholine and piperazine substrates, but the yields for the latter are generally low, ranging from 12% to 41% (Figure 17). Anodic oxidation strategy Another uncommon way to perform α

Effective in silico prediction of new oxazolidinone antibiotics: force field simulations of the antibiotic–ribosome complex supervised by experiment and electronic structure methods

• Jörg Grunenberg and
• Giuseppe Licari

Beilstein J. Org. Chem. 2016, 12, 415–428, doi:10.3762/bjoc.12.45

• throughout) is present in all conformers. 3) The equilibrium H-bond length of 1.70 Å and the calculated relaxed force constant [40] of 0.31 N/cm point to a strong interaction [41], which is decisive for the recognition process. According to experimental results [11], the morpholine ring is not directly

• involved in the molecular recognition process. Our simulation could reproduce this high flexibility of the morpholine moiety, too (see Figure 6). Turning to the conformational changes in the receptor, they seem to be localized at the nucleobases G2540 and U2620 as well at the CCA-N-Phe unit. The

• flexibility of the U2620 (U2585 in Escherichia coli) moiety has already been discussed elsewhere [20]. Nevertheless, due to our simulation, there is no hydrogen bond between this nucleobase and the morpholine ring. The absence of a second hydrogen bond in our simulations (which is indeed observed for