Selective sulfonylation and isonitrilation of para-quinone methides employing TosMIC as a source of sulfonyl group or isonitrile group

• Chuanhua Qu,
• Run Huang,
• Yong Li,
• Tong Liu,
• Yuan Chen and
• Guiting Song

Beilstein J. Org. Chem. 2021, 17, 2822–2831, doi:10.3762/bjoc.17.193

• decompose to a Ts anion and formaldehyde, possibly accompanied by the formation of a cyanide ion [54]. The previous reports on the reaction mechanism of TosMIC as a source of Ts are mainly a radical mechanism [19][20][21][22][23]. To assess the possibility of radical intermediates, a stoichiometric amount

Highly stereocontrolled total synthesis of racemic codonopsinol B through isoxazolidine-4,5-diol vinylation

• Lukáš Ďurina,
• Anna Ďurinová,
• František Trejtnar,
• Ľuboš Janotka,
• Lucia Messingerová,
• Jana Doháňošová,
• Ján Moncol and
• Róbert Fischer

Beilstein J. Org. Chem. 2021, 17, 2781–2786, doi:10.3762/bjoc.17.188

• ) will be obtained by treatment of the deprotected pyrrolidine 2 with formaldehyde under reductive amination conditions. As described in Scheme 2, isoxazolidine-4,5-diol 3 was readily synthesized in four steps according to our procedure [16], starting from commercially available (E)-4

• two steps) under the same reaction conditions when using formaldehyde (37 wt % in H2O). The 1H and 13C NMR spectra recorded on compounds (±)-1 and (±)-2 were in good agreement with those previously reported for the natural sample [1] as well as for the synthetic products [2]. Biological evaluation

• %; (c) 12WO3·H3PO4×H2O, H2O2 (35 wt % in H2O), pyridine, ethyl acetate, rt, 48 h, 70%; (d) BF3·OEt2, CH2Cl2, 0 °C, 15 min, 69%; (e) H2 (1 atm), Pd(OH)2/C (5 wt %), MeOH, rt, 2 h, (±)-2, 71%; (f) H2 (1 atm), Pd(OH)2/C (5 wt %), MeOH, rt, 2 h; then formaldehyde (37 wt % in H2O), H2 (1 atm), Pd(OH)2/C (5

Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives

• Yi Liu,
• Puying Luo,
• Yang Fu,
• Tianxin Hao,
• Xuan Liu,
• Qiuping Ding and
• Yiyuan Peng

Beilstein J. Org. Chem. 2021, 17, 2462–2476, doi:10.3762/bjoc.17.163

• of ammonia, formaldehyde, and acetaldehyde; and iii) preparation from furfural and ammonia. In addition, Hantzsch pyridine synthesis from ethyl acetoacetate, formaldehyde, and ammonia is a commonly used laboratory synthetic method. Recently, extensive and efficient methods for the construction of

• ][28][29]. In industry, pyrrole mainly comes from the extraction of coal tar, the condensation reaction of furan and ammonia under high temperature, or the cascade cyclization reaction of acetylene, formaldehyde, and ammonia. In the laboratory, there are many efficient methods for the synthesis of

Synthesis of phenanthridines via a novel photochemically-mediated cyclization and application to the synthesis of triphaeridine

• Songeziwe Ntsimango,
• Kennedy J. Ngwira,
• Moira L. Bode and
• Charles B. de Koning

Beilstein J. Org. Chem. 2021, 17, 2340–2347, doi:10.3762/bjoc.17.152

• ) would allow for the stabilization of the radical by the methoxy substituent in the ortho position to the departing substituent. The methoxy substituent then presumably loses a hydrogen radical to form acetic acid and intermediate 17c. Further loss of formaldehyde would restore aromaticity and furnish

• . Once intermediate 18b is formed an H+ is abstracted by an acetate ion from the methoxy substituent again forming formaldehyde and acetic acid, along with subsequent quenching of the cation to restore aromaticity. Examples of photoredox-catalyzed cation radical accelerated reactions with the aromatic

Synthesis of O⁶-alkylated preQ₁ derivatives

• Laurin Flemmich,
• Sarah Moreno and
• Ronald Micura

Beilstein J. Org. Chem. 2021, 17, 2295–2301, doi:10.3762/bjoc.17.147

• dibenzylamine–formaldehyde and 2-acylaminopyrrolo[2,3-d]pyrimidin-4(3H)-one as key step, thereby selectively installing a dibenzylaminomethyl moiety [22]. Exchange of the dibenzylamine group in the Mannich base with NH3 provided preQ1 [22]. Alternatively, Klebe demonstrated a Michael addition of 2,6

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• alkyl radical with formaldehyde hydrazone, which resulted in hydrazide 74 that could afford formal hydromethylated compounds 75 after the extrusion of nitrogen and sulfinic acid (Scheme 28) [95]. The hydrazone was generated in situ due its instability, and a simple exchange of the solvent from THF to

Antiviral therapy in shrimp through plant virus VLP containing VP28 dsRNA against WSSV

• Santiago Ramos-Carreño,
• Ivone Giffard-Mena,
• Jose N. Zamudio-Ocadiz,
• Alfredo Nuñez-Rivera,
• Ricardo Valencia-Yañez,
• Jaime Ruiz-Garcia,
• Maria Teresa Viana and
• Ruben D. Cadena-Nava

Beilstein J. Org. Chem. 2021, 17, 1360–1373, doi:10.3762/bjoc.17.95

• 0.002% formaldehyde solution in seawater for 30 min before transferring them to the aquariums to remove any fouling present. Six shrimp were placed per aquarium, containing seawater of 34 ppt at 28 ± 0.3 °C, oxygen between 5.0 to 8.0 mg / L, pH 7.6 ± 0.16 and total ammonium < 0.5 mg/L. A photoperiod of

Icilio Guareschi and his amazing “1897 reaction”

• Gian Cesare Tron,
• Alberto Minassi,
• Giovanni Sorba,
• Mara Fausone and
• Giovanni Appendino

Beilstein J. Org. Chem. 2021, 17, 1335–1351, doi:10.3762/bjoc.17.93

• sheet was then sterilized with phenol and formaldehyde to avoid microbial degradation and eventually flattened to partially recover the original size. Thanks to this very labor-intensive work, almost 3,000 parchment pages could be recovered [63]. Guareschi is considered the father of the scientific

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

• -sulfinyl imine 160. A subsequent base promoted cyclization of chloroamides (158 and 162) and the products 165 and 163 were obtained in 91% and 93% yields respectively. The N-methylation of alkaloids 163 and 165 using 37% formaldehyde and sodium borohydride formed the tetrahydroisoquinoline 164 and 166 in

Stereoselective synthesis and transformation of pinane-based 2-amino-1,3-diols

• Ákos Bajtel,
• Mounir Raji,
• Matti Haukka,
• Ferenc Fülöp and
• Zsolt Szakonyi

Beilstein J. Org. Chem. 2021, 17, 983–990, doi:10.3762/bjoc.17.80

• -amino-1,3-diols, which underwent a regioselective ring closure with formaldehyde or benzaldehyde delivering pinane-condensed oxazolidines. During the preparation of 2-phenyliminooxazolidine, an interesting ring–ring tautomerism was observed in CDCl3. Keywords: 2-amino-1,2-diol; monoterpene; oxazolidin

• necessity to use a stronger reducing agent and more severe conditions. The reduction step, therefore, was performed by applying LAH, a stronger reducing agent, and longer reflux, resulting in N-benzyl-2-amino-1,3-diol 16 (Scheme 4). When compound 16 was treated with formaldehyde at room temperature, pinane

• -diols underwent a regioselective ring closure with formaldehyde and benzaldehyde producing pinane-condensed oxazolidines. In the case of 2-phenyliminooxazolidine, an interesting ring–ring tautomerism was observed in CDCl3. The prepared trifunctional compounds may serve as chiral catalysts in

Enhanced target cell specificity and uptake of lipid nanoparticles using RNA aptamers and peptides

• Roslyn M. Ray,
• Anders Højgaard Hansen,
• Maria Taskova,
• Bernhard Jandl,
• Jonas Hansen,
• Citra Soemardy,
• Kevin V. Morris and
• Kira Astakhova

Beilstein J. Org. Chem. 2021, 17, 891–907, doi:10.3762/bjoc.17.75

• once with PBS and fixed with 4% ice-cold paraformaldehyde (in PBS) for 15 minutes at 4 °C. The formaldehyde was removed and the cells washed twice with ice-cold PBS. Thereafter, PBS containing DAPI (10 ng/mL) was added and the cells visualized using a Zeiss Observer II light microscope with a Zeiss

Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects

• Shivani Gulati,
• Stephy Elza John and
• Nagula Shankaraiah

Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71

• derivatives via a reaction between 5-(4-R-benzyl amino)pyrazoles 137, cyclic 1,3-diketones 6 and formaldehyde (138) in ethanol as solvent. The protocol shows good functional group tolerance with both EDG and EWG on pyrazoles resulting in moderate to good yields (Scheme 53). An interesting observation revealed

• mechanism for the condensation reveals a straight Knoevenagel condensation between 138 and cyclic 1,3-diketones directing to Knoevenagel adduct A. A Michael type addition at the C-4 position of 137 with adduct A results in intermediate B. Finally in presence of another molecule of formaldehyde intermediate

A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles

• Bingbing Lai,
• Meng Ye,
• Ping Liu,
• Minghao Li,
• Rongxian Bai and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2888–2902, doi:10.3762/bjoc.16.238

• , the support was prepared through phenol–formaldehyde condensation reaction of LS and FAS. The FAS was chosen to embellish LS in consideration of the following reason: FAS skeleton consists of both aldehyde and sulfonic groups, so the grafting of FAS and LS can be easily realized via phenol

• –formaldehyde condensation reaction, and therefore equips the generated polymeric support with more sulfonic groups. The heterogeneous Cu catalyst (LS-FAS-Cu) was finally obtained through refluxing of LS-FAS with Cu(OTf)2 in ethanol, and the loading capacity of Cu was confirmed to be 0.92 mmol/g by means of ICP

• . For comparison, two controlled heterogeneous catalysts, namely Resin-Cu and LS-FM-Cu were prepared using commercially available Amberlyst-15 and the material [13] was synthesized by condensation of formaldehyde and LS as supports, respectively (see Supporting Information File 1, Figure S1 and Figure

Host–guest interaction of cucurbit[8]uril with oroxin A and its effect on the properties of oroxin A

• Zhishu Zeng,
• Jun Xie,
• Guangyan Luo,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 2332–2337, doi:10.3762/bjoc.16.194

• the inclusion compound with Q[8]. Keywords: cucurbit[8]uril; host–guest interaction; inclusion complex; oroxin A; properties; Introduction Cucurbit[n]urils (Q[n]s) are a family of macrocyclic cage compounds synthesized by the condensation of glycoluril and formaldehyde in a strong acidic solution [1

Tuneable access to indole, indolone, and cinnoline derivatives from a common 1,4-diketone Michael acceptor

• Dalel El-Marrouki,
• Sabrina Touchet,
• Abderrahmen Abdelli,
• Hédi M’Rabet,
• Mohamed Lotfi Efrit and
• Philippe C. Gros

Beilstein J. Org. Chem. 2020, 16, 1722–1731, doi:10.3762/bjoc.16.144

• ). The nitrenones 3a–d were obtained in three steps from the appropriate commercially available cyclohexenones (Scheme 2). First, a Baylis–Hillman reaction between cyclohexanone and formaldehyde led to the formation of the corresponding Baylis–Hillman alcohols 1a/b in good yield [58], followed by a DMAP

Recent synthesis of thietanes

• Jiaxi Xu

Beilstein J. Org. Chem. 2020, 16, 1357–1410, doi:10.3762/bjoc.16.116

• synthesis of thietane-containing spironucleosides. The easily available 5-aldo-3-O-benzyl-1,2-O-isopropylidene-α-D-glucofuranose (36) was first treated with formaldehyde in the presence of NaOH followed by MsCl, affording the dimesylate derivative 38, which was reacted with Na2S to afford the spirothietane

Activated carbon as catalyst support: precursors, preparation, modification and characterization

• Melanie Iwanow,
• Tobias Gärtner,
• Volker Sieber and
• Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

• adding a reducing agent, such as hydrogen, formaldehyde or sodium borohydride [1]. Is the drying step replaced by filtration of the large excess of solution, the method is called ionic adsorption [134][137]. Deposition

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• ]. Recently, they reported that formaldehyde (35) could also act as a photoinitiator when employed for photografting even though it was not as efficient as acetone (4) (Scheme 10) [45]. The proposed mechanism of action is depicted in Scheme 11. The same research group extended their study and found that

• acetaldehyde (36) was also capable of initiating the photografting of methacrylic acid (MAA, 42) onto HDPE, highlighting that acetaldehyde (36) is a better initiator that outperformed formaldehyde (35) and acetone (4) [46]. In more detail, in 2011, Wang and co-workers studied the efficiency of acetaldehyde (36

• acetone (4) and formaldehyde (35) in initiating the photografting in an aqueous solution. The maximum extent of grafting was observed for 10 wt % of 36. The concentration of 42 also affected the extent of photografting. The extent of grafting increased with the increase of the monomer up to 2 mol/L and

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• pyrrolylphosphine ligands 40 and 43 was reported by Kumar et al. [68] (Scheme 7). The condensation of pyrrole (38) with formaldehyde and the amine gave the bis(diaminomethyl)pyrrole 39, which on reaction with Ph2PH gave diphosphine pyrrole ligand 40 in good yield (90%). Following a different route, condensation of

• was very low after trapping 75 with diphenylchlorophosphine [79]. The PTA motif is water soluble, thermally, air and moisture stable. The PTA building block can be synthesized by coupling tris(hydroxymethyl)phosphine (73) with formaldehyde and ammonia in ice water or with hexamethylenetetramine. A

Carbazole-functionalized hyper-cross-linked polymers for CO₂ uptake based on Friedel–Crafts polymerization on 9-phenylcarbazole

• Dandan Fang,
• Xiaodong Li,
• Meishuai Zou,
• Xiaoyan Guo and
• Aijuan Zhang

Beilstein J. Org. Chem. 2019, 15, 2856–2863, doi:10.3762/bjoc.15.279

• HCPs include solvent knitting methods [10], Scholl coupling reaction [11], the knitting method with formaldehyde dimethyl acetal (FDA) [12], functional group reactions [2][13] and so on. Among these methods, the knitting method with FDA as external cross-linker is the most time-efficient approach [14

Chemical tuning of photoswitchable azobenzenes: a photopharmacological case study using nicotinic transmission

• Lorenzo Sansalone,
• Jun Zhao,
• Matthew T. Richers and
• Graham C. R. Ellis-Davies

Beilstein J. Org. Chem. 2019, 15, 2812–2821, doi:10.3762/bjoc.15.274

• maleimide using hydroxymethylation with formaldehyde, followed by treatment with thionyl chloride to give a chloromethyl intermediate, which was reacted in situ with maleimide to give 1 in 6% overall yield. Crucially, photochrome 1 also maintained the near-ideal photochemical properties of Hecht’s 4FABs [12

Plasma membrane imaging with a fluorescent benzothiadiazole derivative

• Pedro H. P. R. Carvalho,
• Jose R. Correa,
• Karen L. R. Paiva,
• Daniel F. S. Machado,
• Jackson D. Scholten and
• Brenno A. D. Neto

Beilstein J. Org. Chem. 2019, 15, 2644–2654, doi:10.3762/bjoc.15.257

• formaldehyde 3.7% for 30 minutes. Again, the cells were washed three times in PBS 1X (pH 7.4) at room temperature and the coverslips were mounted over glass slides using ProLong Gold Antifade (Invitrogen, OR, USA) according to the manufacturer’s recommendations. A similar procedure was followed for fixed cells

• . Fixed cells were washed three times in PBS 1X (pH 7.4) and then fixed in formaldehyde 3.7% for 30 minutes. Afterwards, fixed cells were washed three times in PBS 1X (pH 7.4) at room temperature and incubated for 30 minutes with BTD-4APTEG solution (1 μM) at room temperature, washed three times in PBS 1X

Chiral terpene auxiliaries V: Synthesis of new chiral γ-hydroxyphosphine oxides derived from α-pinene

• Anna Kmieciak and
• Marek P. Krzemiński

Beilstein J. Org. Chem. 2019, 15, 2493–2499, doi:10.3762/bjoc.15.242

• with sodium methoxide in toluene and the resulting enolate was condensed with ethyl formate to give a keto-aldehyde, which tautomerized into the more stable β-hydroxyenone 4 [23]. The intermediate 4 was sufficiently pure for the subsequent transaldolization reaction with formaldehyde in the presence of

• to the allylic alcohol. Thus, Claisen condensation of 8 with ethyl formate gave β-hydroxyenone 9, which was subjected to transaldolization with formaldehyde producing the corresponding 4-methyleneisopinocamphone (10) in 83% yield. Luche reduction of the latter compound provided (1R,2R,3R,5R)-4

In water multicomponent synthesis of low-molecular-mass 4,7-dihydrotetrazolo[1,5-a]pyrimidines

• Irina G. Tkachenko,
• Sergey A. Komykhov,
• Vladimir I. Musatov,
• Svitlana V. Shishkina,
• Viktoriya V. Dyakonenko,
• Vladimir N. Shvets,
• Mikhail V. Diachkov,
• Valentyn A. Chebanov and
• Sergey M. Desenko

Beilstein J. Org. Chem. 2019, 15, 2390–2397, doi:10.3762/bjoc.15.231

• , Ukraine Bar-Ilan University Ramat Gan, 5290002, Israel 10.3762/bjoc.15.231 Abstract The three-component reaction of 5-aminotetrazole with aliphatic aldehydes (formaldehyde, acetaldehyde) and acetoacetic ester derivatives in water under microwave irradiation leads to the selective formation of 4,7

• Da. Therefore, the minimization of molecular masses for the targeted tetrazolo[1,5-a]pyrimidines can be achieved by exclusion of large aryl substituents from their structures. Thus, we selected aliphatic aldehydes, i.e., formaldehyde and acetaldehyde, as the starting material and chose a

• promising for further detailed studies. Conclusion The three-component method which is based on the in-water reaction of 5-aminotetrazole with 1,3-dicarbonyl compounds and aliphatic aldehydes, like formaldehyde or acetaldehyde, under microwave activation, was applied for the preparation of low-molecular

A review of the total syntheses of triptolide

• Xiang Zhang,
• Zaozao Xiao and
• Hongtao Xu

Beilstein J. Org. Chem. 2019, 15, 1984–1995, doi:10.3762/bjoc.15.194

• corresponding N-oxide followed by Cope elimination gave olefin 62. Cleavage of olefin 62 with OsO4 and NaIO4 afforded ketone intermediate 10, which was enolized by (iPr)2NLi (LDA) and further reacted with formaldehyde to afford hydroxy ketone 63. Protection of the hydroxy group of 63 as 2-methoxypropyl ether