One-pot synthesis of 1,3,5-triazine-2,4-dithione derivatives via three-component reactions

• Gui-Feng Kang and
• Gang Zhang

Beilstein J. Org. Chem. 2020, 16, 1447–1455, doi:10.3762/bjoc.16.120

• 100050, China 10.3762/bjoc.16.120 Abstract A catalyst-free one-pot synthetic methodology was developed for the preparation of 1,3,5-triazine-2,4-dithione derivatives through three-component reactions of arylaldehydes, thiourea, and orthoformates. The procedure tolerated a diverse range of arylaldehydes

• and orthoformates and provided a rapid entry to a variety of 4-aryl-6-(alkylthio)-3,4-dihydro-1,3,5-triazine-2(1H)-thiones (29 examples). The synthetic strategy relies on the dual role of thiourea in the cyclization with the aldehydes and the alkylation via an intermediate imidate formation. The

• structures of 1,3,5-triazine-2,4-dithione derivatives were characterized by spectroscopic techniques as well as by single crystal X-ray diffraction. Keywords: aldehydes; multicomponent reactions; nitrogen heterocycles; thiourea; triazinethiones; Introduction The construction of nitrogen-containing

Recent synthesis of thietanes

• Jiaxi Xu

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

• displacements of 1,3-dihaloalkanes with different sulfide salts, thiourea was also used as a nucleophile in the double displacements, actually following the preparation procedure of thiols, affording thietane derivatives. Thiourea reacted with 3,3-bis(chloromethyl)oxetane (76) in the presence of HClO4 to yield

A systematic review on silica-, carbon-, and magnetic materials-supported copper species as efficient heterogeneous nanocatalysts in “click” reactions

• Pezhman Shiri and
• Jasem Aboonajmi

Beilstein J. Org. Chem. 2020, 16, 551–586, doi:10.3762/bjoc.16.52

Regio- and stereoselective synthesis of new ensembles of diversely functionalized 1,3-thiaselenol-2-ylmethyl selenides by a double rearrangement reaction

• Svetlana V. Amosova,
• Andrey A. Filippov,
• Nataliya A. Makhaeva,
• Alexander I. Albanov and
• Vladimir A. Potapov

Beilstein J. Org. Chem. 2020, 16, 515–523, doi:10.3762/bjoc.16.47

• proceeding at the C2 carbon atom of the seleniranium cation 2 with dithiocarbomates [31], thiourea [32], alcohols [42], functionalized organic acids [43][44], functionalized pyridines [45], ammonium thiocyanate [46], and mercapto benzazoles [40] were developed (Scheme 4). The new methodology of a

The use of isoxazoline and isoxazole scaffolding in the design of novel thiourea and amide liquid-crystalline compounds

• Itamar L. Gonçalves,
• Rafaela R. da Rosa,
• Vera L. Eifler-Lima and
• Aloir A. Merlo

Beilstein J. Org. Chem. 2020, 16, 175–184, doi:10.3762/bjoc.16.20

• Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal Institute of Chemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil 10.3762/bjoc.16.20 Abstract A series of novel thiourea and amide liquid crystals containing 5-membered isoxazoline and isoxazole rings

• . Thiourea and amide derivatives were predominantly SmA mesophase inductors. A nematic mesophase was observed only for thioureas and amides containing an isoxazole ring. Additionaly, the liquid crystal behavior was also dependent on the relative position of nitrogen and oxygen atoms on the 5-membered

• heterocycle. Keywords: amides; isoxazole; isoxazoline; liquid crystal; thiourea; Introduction Thioureas are a structurally diversified group of organic compounds, with technological applications in different areas. The structural diversity of the thiourea moiety is linked to possibly one or both nitrogen

The reaction of arylmethyl isocyanides and arylmethylamines with xanthate esters: a facile and unexpected synthesis of carbamothioates

• Narasimhamurthy Rajeev,
• Toreshettahally R. Swaroop,
• Ahmad I. Alrawashdeh,
• Shofiur Rahman,
• Abdullah Alodhayb,
• Seegehalli M. Anil,
• Kuppalli R. Kiran,
• Chandra,
• Paris E. Georghiou,
• Kanchugarakoppal S. Rangappa and
• Maralinganadoddi P. Sadashiva

Beilstein J. Org. Chem. 2020, 16, 159–167, doi:10.3762/bjoc.16.18

• ], iron nanoparticle-catalyzed reactions of 2-naphthol with benzaldehyde and some of its derivatives with thiourea [22], isothiocyanato oxindoles with ketones [23], ammonium isothiocyanates with chalcones [24], and α-isothiocyanato esters with α-keto amides [25]. Among the synthetic methods available for

Why do thioureas and squaramides slow down the Ireland–Claisen rearrangement?

• Dominika Krištofíková,
• Juraj Filo,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2019, 15, 2948–2957, doi:10.3762/bjoc.15.290

• rearrangement, we tried to optimize its reaction course under mild conditions using various bases, solvents, and hydrogen-bond-donating catalysts. We also present a computational explanation and NMR kinetic study for the inefficient Ireland–Claisen rearrangement under thiourea and squaramide catalysis. Results

• . For this, we have compared the uncatalyzed Ireland–Claisen rearrangement with three hydrogen-bond-catalyzed reactions. As model H-bonding catalysts, we selected diphenylthiourea, Schreiner thiourea, and the corresponding squaramide with bis(trifluoromethyl)phenyl groups. We have evaluated both the (E

• Schreiner thiourea (C12) had higher activation barriers for both isomers (111.9 kJ·mol−1 for (E) and 95.6 kJ·mol−1 for (Z)). These results suggest that Schreiner thiourea binds stronger to starting silyl ketene acetal than to the corresponding transition state. Therefore, it stabilizes more the starting

Facile regiodivergent synthesis of spiro pyrrole-substituted pseudothiohydantoins and thiohydantoins via reaction of [e]-fused 1H-pyrrole-2,3-diones with thiourea

• Aleksandr I. Kobelev,
• Nikita A. Tretyakov,
• Ekaterina E. Stepanova,
• Maksim V. Dmitriev,
• Michael Rubin and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2019, 15, 2864–2871, doi:10.3762/bjoc.15.280

• good yields, and the products were isolated without applying preparative chromatography methods. Keywords: diversity-oriented synthesis; hydantoin; nitrogen heterocycles; rearrangement; thiourea; Introduction Hydantoin (imidazolidine-2,4-dione) derivatives are omnipresent among biologically active

• preparation of the target spiro-fused pseudothiohydantoins and thiohydantoins, we examined the reaction of FPD 1a with thiourea by heating equimolar amounts of the reagents in toluene for 5 min (until the disappearance of the dark violet color of FPD 1a). The reaction mixture was examined by UPLC–MS. Two

• major products with m/z = 396 ([M + H]+, ESI+) were observed in a ratio of ≈1:1, which corresponded to adducts of thiourea with FPD 1a. The adducts were isolated, and their structures were elucidated as the desired spiro-fused thiohydantoin 2a and pseudothiohydantoin 3a (Scheme 4). It should be pointed

Diversity-oriented synthesis of spirothiazolidinediones and their biological evaluation

• Sambasivarao Kotha,
• Gaddamedi Sreevani,
• Lilya U. Dzhemileva,
• Milyausha M. Yunusbaeva,
• Usein M. Dzhemilev and
• Vladimir A. D’yakonov

Beilstein J. Org. Chem. 2019, 15, 2774–2781, doi:10.3762/bjoc.15.269

• synthesis of thiazolidinedione derivatives is refluxing chloroacetic acid (2) with thiourea (1), followed by a Knoevenagel condensation with an aldehyde (Scheme 1) [25]. Results and Discussion Limited reports are available dealing with the synthesis of spiro derivatives of thiazolidine-2,4-diones [26][27

A novel three-component reaction between isocyanides, alcohols or thiols and elemental sulfur: a mild, catalyst-free approach towards O-thiocarbamates and dithiocarbamates

• András György Németh,
• György Miklós Keserű and
• Péter Ábrányi-Balogh

Beilstein J. Org. Chem. 2019, 15, 1523–1533, doi:10.3762/bjoc.15.155

• -diimidazole or di-2-pyridyl thionocarbonate [57][58]. Decomposition of dithiocarbamate salts or thiocarbamates with various reagents offers a good alternative [59][60][61][62] as well, however, this approach first requires the synthesis of the appropriate precursor. Nitrile oxides react with thiourea to

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• reagents as aforementioned or DTT 1 with thiourea or thioacetate in a Pd-catalyzed reaction [33] led in both cases to substantially lower yields. For the synthesis of selenolotriacenes (DST) 3 and (DSS) 4 we followed the same strategies and applied the above described Cu-catalyzed C–S and C–Se cross

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• 40 (Scheme 13). An alternative setup of Biginelli-3CR with steroids was reported by Boruah and co-workers [43] using ultrasound assistance instead of microwave irradiation or thermal heating. In this case, the reaction between cholestanic ketone 43, an alkyl or arylaldehyde, and urea or thiourea

Metal-free C–H mercaptalization of benzothiazoles and benzoxazoles using 1,3-propanedithiol as thiol source

• Yan Xiao,
• Bing Jing,
• Xiaoxia Liu,
• Hongyu Xue and
• Yajun Liu

Beilstein J. Org. Chem. 2019, 15, 279–284, doi:10.3762/bjoc.15.24

• three-component reaction of o-iodoanilines and K2S in DMSO [20]. Another way to prepare 2-mercaptobenzothiazoles and 2-mercaptobenzoxazoles is the nucleophilic substitution of 2-halo-substituted benzothiazoles and benzoxazoles with sulfur-containing reagents including sodium thiosulfate [21], thiourea

First synthesis of cryptands with sucrose scaffold

• Patrycja Sokołowska,
• Michał Kowalski and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2019, 15, 210–217, doi:10.3762/bjoc.15.20

• convenient chiral platform for such macrocycles [9][10]. Several of them, such as 5 (Figure 1), are able to differentiate enantiomers of α-phenylethylammonium salt [11][12]. Sucrose dimers containing two urea or thiourea units (6 or 7) are able to complex anions [13][14]. More complex derivatives with

Asymmetric Michael addition reactions catalyzed by calix[4]thiourea cyclohexanediamine derivatives

• Zheng-Yi Li,
• Hong-Xiao Tong,
• Yuan Chen,
• Hong-Kui Su,
• Tangxin Xiao,
• Xiao-Qiang Sun and
• Leyong Wang

Beilstein J. Org. Chem. 2018, 14, 1901–1907, doi:10.3762/bjoc.14.164

• Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China 10.3762/bjoc.14.164 Abstract A number of upper rim-functionalized calix[4]thiourea cyclohexanediamine derivatives have been designed, synthesized and used as catalysts for enantioselective Michael addition reactions between

• nitroolefins and acetylacetone. The optimal catalyst 2 with a mono-thiourea group exhibited good performance in the presence of water/toluene (v/v = 1:2). Under the optimal reaction conditions, high yields of up to 99% and moderate to good enantioselectivities up to 94% ee were achieved. Detailed experiments

• clearly showed that the upper rim-functionalized hydrophobic calixarene scaffold played an important role in cooperation with the catalytic center to the good reactivities and enantioselectivities. Keywords: asymmetric Michael addition reaction; calix[4]arene; cyclohexanediamine; thiourea; Introduction

Water-soluble SNS cationic palladium(II) complexes and their Suzuki–Miyaura cross-coupling reactions in aqueous medium

• Alphonse Fiebor,
• Richard Tia,
• Banothile C. E. Makhubela and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1859–1870, doi:10.3762/bjoc.14.160

• reactions [32][33]. As it was elegantly reviewed by Singh and co-workers [33], these organosulfur ligands can be classified into pincer type (symmetrical and unsymmetrical), thioethers, thiourea-based ligands, sulfur-substituted NHCs, thiosemicarbazones and sulfated Schiff bases. Of the pincer ligands

Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• -cyclohepten-1-one and chalcone were also tested as substrates for the Michael addition reaction and the corresponding adducts were obtained in good yield with moderate enantioselectivity (13–23% ee). Calixarene-derived thiourea seemed to be an interesting backbone for design of new organocatalysts for

• asymmetric synthesis. In 2013, we described a novel class of calix[4]arene-based chiral primary amine–thiourea catalysts 47a and 47b derived from p-tert-butylcalix[4]arene (Figure 7) [49]. To evaluate the catalytic efficiency, bifunctional catalysts were applied to promote the Michael addition of aldehydes

• of the achiral calixarene platform, the monomeric analogue carrying both thiourea and primary amine subunits was also prepared and used in the control experiments. Under optimal reaction conditions, the noncyclic analogue afforded the product in lower yields and enantioselectivities (52% yield, 89

Synthesis of chiral 3-substituted 3-amino-2-oxindoles through enantioselective catalytic nucleophilic additions to isatin imines

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 1349–1369, doi:10.3762/bjoc.14.114

• first asymmetric organocatalytic synthesis of chiral 3-amino-2-oxindoles based on enantioselective aza-Morita–Baylis–Hillman reaction of N-Boc-isatin imines 3 with activated nitroolefins 39 [62]. The best results were achieved by using cinchona alkaloid-derived thiourea catalyst 40 in toluene at −10 °C

• -isatin imines 3 with naphthols performed in the presence of cinchona alkaloid-derived thiourea 40 [66]. As shown in Scheme 15, the reaction of 1-naphthols 42 promoted by 2 mol % of this bifunctional catalyst in toluene at room temperature led to the corresponding chiral 3-substituted 3-amino-2-oxindoles

• Friedel–Crafts reaction of N-Boc-isatin imines 3 with 6-hydroxyquinolines 48 promoted by the cinchona alkaloid-derived thiourea 40 [68]. The process was performed in toluene at room temperature to give the corresponding chiral 3-amino-2-oxindoles 49 bearing a quinoline moiety in moderate to excellent

Oligonucleotide analogues with cationic backbone linkages

• Melissa Meng and
• Christian Ducho

Beilstein J. Org. Chem. 2018, 14, 1293–1308, doi:10.3762/bjoc.14.111

• of DNG oligomers were introduced. They enabled chain elongation either in the 5'→3' [52] or 3'→5' [53] direction, respectively. Starting from protected 3',5'-dideoxy-5'-amino-3'-azidothymidine 21, the 5'→3' route was based on the synthesis of the diamino intermediate 22 and thiourea monomer 23, which

• the cleavage conditions used in the solid phase-supported synthesis of native DNA and also allowed the introduction not only of pyrimidine, but also of purine bases into the oligonucleotide analogue [53]. The method was based on the activation of the 5′-monomethoxytrityl (MMTr)-protected 3'-thiourea

• -deprotection cycle afforded thiourea-linked oligonucleotide analogue 41. Subsequent reaction of the thiourea internucleotide linkages with methyl iodide furnished the protected S-methylthiourea-linked oligomer 42 and finally, after cleavage from the solid support and acidic deprotection, the envisioned DNmt

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

• synthesis of 7-hydroxy-2,3-benzotropone (241) was successfully realized by Dastan’s group (Scheme 47) [149]. Thiourea reduction of the peroxide linkage of 213 to the diol 282 and then simultaneously dehydration in situ gave the corresponding benzotropolone 241 in nearly quantitative yield. Recently, Arican

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

Investigations towards the stereoselective organocatalyzed Michael addition of dimethyl malonate to a racemic nitroalkene: possible route to the 4-methylpregabalin core structure

• Denisa Vargová,
• Rastislav Baran and
• Radovan Šebesta

Beilstein J. Org. Chem. 2018, 14, 553–559, doi:10.3762/bjoc.14.42

• addition of dimethyl malonate. An initial catalyst screening was performed in dichloromethane, based on our previous experiences with this type of Michael additions [18]. We have employed a range of squaramide and thiourea organocatalysts C1–C7 [18][27][28][29][30][31][32][33][34], as well as two newly

Recent developments in the asymmetric Reformatsky-type reaction

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 325–344, doi:10.3762/bjoc.14.21

• containing the two substrates with LiCl was pumped through the zinc column followed by a scavenger cartridge containing QuadraPure polymer-supported sulfonic acid and polymer-supported thiourea. This allowed diastereopure product 36 (98% de) to be obtained in 70% yield. Intramolecular Reformatsky reactions

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

• lactim ethers [50]. For the preparation of 2-thioxopyrimidinones 7, 8a and 8b, the most common method is the reaction of the appropriate amino esters with phenyl isothiocyanate, followed by cyclization of the resulting thiourea with hydrogen chloride under reflux [45][49]. The starting materials were

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

• development of chiral bifunctional urea 1 [35], thiourea 2 and 3 [36][37], sulfonamide 4 [38][39][40] and squaramide 5 [38][39][40] catalysts derived from chloramphenicol base (Figure 1), which showed excellent reactivity and enantioselectivity for this asymmetric transformation. A typical example of the

• chloramphenicol-derived bifunctional amide organocatalysts and their application for enantioselective alcoholysis of meso-cyclic anhydrides. In the precedented urea- or thiourea-based organocatalytic methanolysis of anhydrides, one big problem is the homo-aggregation of the catalysts via hydrogen bonding, which