From dipivaloylketene to tetraoxaadamantanes

• Gert Kollenz and
• Curt Wentrup

Beilstein J. Org. Chem. 2018, 14, 1–10, doi:10.3762/bjoc.14.1

• crown-5 derivative 31 showed an enhanced ability to extract Na+ and K+ ions from water into CHCl3 (22 and 21%, respectively, within 10 minutes using equimolar amounts of salt and ligand) [37]. In the concave structures of the bisdioxines, the functional groups such as esters, amides, carbamates

Rh(II)-mediated domino [4 + 1]-annulation of α-cyanothioacetamides using diazoesters: A new entry for the synthesis of multisubstituted thiophenes

• Jury J. Medvedev,
• Ilya V. Efimov,
• Yuri M. Shafran,
• Vitaliy V. Suslonov,
• Vasiliy A. Bakulev and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2017, 13, 2569–2576, doi:10.3762/bjoc.13.253

• reactions of acyclic diazoesters with α-cyanothioacetamides. It provides a way for the preparation of 5-amino-3-(alkoxycarbonylamino)thiophene-2-carboxylates, 2-(5-amino-2-methoxycarbonylthiophene-3-yl)aminomalonates and (2-cyano-5-aminothiophene-3-yl)carbamates with the preparative yields of up to 67%. It

• -aminothiophen-3-yl)carbamates 5, which could be formally referred to as the derivatives of carbamates 3, 5 and heteroaromatic amines 4. To elucidate the reasons for the low reactivity of diazoesters 2a,b with thioamides 1 in the considered catalytic processes, the interaction of thioacetamides 1a–e with Rh2(Piv

• ylide with the rhodium catalyst. Within the adopted general scheme, the occurrence of thiophenes 4 could be rationalized by partial hydrolysis of carbamates 3 under the reaction conditions with the initial formation of the primary heteroaromatic amines 7. The latter then interact with carbenoids A, to

Diosgenyl 2-amino-2-deoxy-β-D-galactopyranoside: synthesis, derivatives and antimicrobial activity

• Henryk Myszka,
• Patrycja Sokołowska,
• Agnieszka Cieślińska,
• Andrzej Nowacki,
• Maciej Jaśkiewicz,
• Wojciech Kamysz and
• Beata Liberek

Beilstein J. Org. Chem. 2017, 13, 2310–2315, doi:10.3762/bjoc.13.227

• the condensation of saccharides with ureas or the reaction of glycosylamines, amino sugar, or aminoglycosides with isocyanates, or their equivalents such as carbamates [32][33]. Ureido saponins presented here were obtained in the reaction of ethyl isocyanate (8), chloroethyl isocyanate (9) and phenyl

Regiodivergent condensation of 5-alkoxycarbonyl-1H-pyrrol-2,3-diones with cyclic ketazinones en route to spirocyclic scaffolds

• Alexey Yu. Dubovtsev,
• Maksim V. Dmitriev,
• Аndrey N. Maslivets and
• Michael Rubin

Beilstein J. Org. Chem. 2017, 13, 2179–2185, doi:10.3762/bjoc.13.218

• (vinylogous carbonates and carbamates) normally requires more forcing conditions, but usually can be facilitated by addition of catalytic amounts of organic base (Scheme 2) [43]. Interestingly, we figured out that the presence of heteroatom X in the structure of enol 6 is important for the normal course of

• -catalyzed spirocyclization of enoles (vinylogous carbonates and carbamates) with 5-methoxycarbonyl-1H-pyrrolediones. Acid-catalyzed spirocyclization of enoles (vinylogous carboxylates) with 5-alkoxycarbonyl-1H-pyrrolediones. Formation of mono-imines and mono-hydrazones of 1,3-cyclohexanediones and

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

• 65–81% of trans-esterified product (Scheme 21). Differently substituted benzene rings including hetero-aromatics were also well tolerated under the similar condition. Colacino and co-workers reported the preparation of carbamates by using 1,1’-carbonyldiimidazole (CDI) and in presence of either

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

Transition-metal-catalyzed synthesis of phenols and aryl thiols

• Yajun Liu,
• Shasha Liu and
• Yan Xiao

Beilstein J. Org. Chem. 2017, 13, 589–611, doi:10.3762/bjoc.13.58

• Ackermann group used another ruthenium catalyst, [RuCl2(p-cymene)]2 and developed a hydroxylation protocol for carbamates [77]. The hydroxylation occurred in DCE in the presence of PhI(OTFA)2 (Scheme 47). In intermolecular competition experiments, among amide, carbamate and ester, amide showed the highest

• ketones. The Rao group developed a catalytic system of [RuCl2(p-cymene)]2 and K2S2O8 in TFA/TFAA, which promoted the hydroxylation of ethyl benzoates, benzamides and carbamates (Scheme 49). They reported the first ortho-hydroxylation of ethyl benzoates in 2012 [79]. Both electron-rich and electron

• , CF3, ester, etc.) and electron-donating functional groups (such as methyl, methoxy, etc) were well tolerated. In 2014, the tolerance of this protocol for carbamates and esters was studied [81]. Carbamates were compatible with this protocol, however, esters gave lower yields. A replacement of [RuCl2(p

Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis

• Flavio Fanelli,
• Giovanna Parisi,
• Leonardo Degennaro and
• Renzo Luisi

Beilstein J. Org. Chem. 2017, 13, 520–542, doi:10.3762/bjoc.13.51

• (0.33 ms) under cryogenic conditions. By using such an incredible short residence time, it was possible to overtake the very rapid anionic Fries rearrangement, and chemoselectively functionalize ortho-lithiated aryl carbamates (Scheme 7). This CMR has been developed choosing a fluoroethylene propylene

Solution-phase automated synthesis of an α-amino aldehyde as a versatile intermediate

• Hisashi Masui,
• Sae Yosugi,
• Shinichiro Fuse and
• Takashi Takahashi

Beilstein J. Org. Chem. 2017, 13, 106–110, doi:10.3762/bjoc.13.13

• serinate using Fmoc–OSu or CbzCl afforded the corresponding carbamates in good yields (Table 1, experimental details, see Supporting Information File 1). Acetal formation and reduction were performed by the developed procedure in ChemKonzert (Table 1). The Garner’s aldehydes containing an Fmoc or Cbz

• protecting group (PG) could be synthesized from the corresponding methyl ester; however, lower yields were obtained for the DIBAL reduction, probably due to the DIBAL-mediated removal of the carbamates [32]. Conclusion In conclusion, the first solution-phase automated synthesis of 4a (Boc protection) was

Robust C–C bonded porous networks with chemically designed functionalities for improved CO₂ capture from flue gas

• Damien Thirion,
• Joo S. Lee,
• Ercan Özdemir and
• Cafer T. Yavuz

Beilstein J. Org. Chem. 2016, 12, 2274–2279, doi:10.3762/bjoc.12.220

• formation. Carbamates form with the contribution of two amines and carbamic acid needs one amine and a water molecule. The presence of moisture, therefore, favors the formation of carbamic acids and leads to higher uptake capacity per sorbent mass. We performed moist CO2 uptake experiments in order to mimic

p-Nitrophenyl carbonate promoted ring-opening reactions of DBU and DBN affording lactam carbamates

• Madhuri Vangala and
• Ganesh P Shinde

Beilstein J. Org. Chem. 2016, 12, 2086–2092, doi:10.3762/bjoc.12.197

• towards highly electrophilic p-nitrophenyl carbonate derivatives with ring opening of the bicyclic ring to form corresponding substituted ε-caprolactam and γ-lactam derived carbamates. This simple method presents a unified strategy to synthesize structurally diverse ε-caprolactam and γ-lactam compounds

• behavior of DBU towards imidazolides providing ε-caprolactam-derived carbamates and amides [17]. Here, in this report we present the results obtained by the reaction of DBU and DBN with highly electrophilic p-nitrophenyl carbonates leading to ε-caprolactam and γ-lactam carbamates. p-Nitrophenyl carbonates

• in the solvent, leading to the ring opening and formation of the corresponding caprolactam carbamates (Scheme 1). The structure of 1b was confirmed by 1H and 13C spectroscopy, which showed the characteristic carbamate NH triplet at 5.80 ppm in the 1H NMR spectrum and the expected peaks at 176.6 and

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• ). Similarly, silyl reagents also failed to afford the desirable products under the optimized conditions. Based on above observations and understandings toward the mechanism, a modified protocol was designed by introducing the secondary amide containing reagents such as allylsilanes, carbamates, etc, where the

Beyond catalyst deactivation: cross-metathesis involving olefins containing N-heteroaromatics

• Kevin Lafaye,
• Cyril Bosset,
• Lionel Nicolas,
• Amandine Guérinot and
• Janine Cossy

Beilstein J. Org. Chem. 2015, 11, 2223–2241, doi:10.3762/bjoc.11.241

• including alcohols, halides, esters, amides, carbamates and sulfonamides are compatible with the metathesis conditions [14][15][16][17][18][19][20]. However, the involvement of alkenes containing a nitrogen atom such as an amine or an N-heteroaromatic ring in metathesis reactions is still problematic and

• allow the use of primary and secondary amines in ring-closing metathesis (RCM) and cross-metathesis (CM), and one of them is the transformation of amines into carbamates, amides or sulfonamides [27][28][29]. As an alternative, metathesis reactions can be performed with olefins possessing ammonium salts

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

• cyclic imides, carbamates, sulfonamides and indoles. On the other hand, the successful amidation using different alkynes, including aryl-, alkyl- and silyl-functionalized alkynes proved the broad scope of application of this method (Scheme 19). Following the design of this method, a heterogeneous

• catalytic protocol was later developed by Mizuno et al. [74] for the amidation of terminal alkynes using lactam, sulfonamide or cyclic carbamates. The application of Cu(OH)2 as heterogeneous catalyst allowed the synthesis of ynamides 77 with moderate to excellent yield under air (Scheme 20). A latest work

Why base-catalyzed isomerization of N-propargyl amides yields mostly allenamides rather than ynamides

• Armando Navarro-Vázquez

Beilstein J. Org. Chem. 2015, 11, 1441–1446, doi:10.3762/bjoc.11.156

• Armando Navarro-Vazquez Departamento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco, Cidade Universitária - Recife, PE - CEP 50.740-560, Brazil 10.3762/bjoc.11.156 Abstract The base-catalyzed isomerization of N-propargylamides or carbamates may

• employing harsh reaction conditions. The outcome of the isomerization process seems to subtlety depend on the structural features of the N-propargyl compound. Similar issues have been observed for carbamates or phosphoramides [8]. In summary, the isomerization process is not yet well understood and, quoting

• for the corresponding isomers for a selected combination of starting amides or carbamates and a final urea example (Figure 1) were computed using ab initio and DFT methods. Results and Discussion Computational procedures It is known that ab initio prediction of cumulene–polyynes isomerization energies

Diastereoselective and enantioselective conjugate addition reactions utilizing α,β-unsaturated amides and lactams

• Katherine M. Byrd

Beilstein J. Org. Chem. 2015, 11, 530–562, doi:10.3762/bjoc.11.60

• work for electron-deficient anilines. Despite this limitation, Hii and co-workers expanded the methodology to other α,β-unsaturated N-alkenoylbenzamides [238] and carbamates [239][240] (Scheme 32). In order to find means to overcome the low enantioselectivities observed when electron-rich anilines are

Molecular cleft or tweezer compounds derived from trioxabicyclo[3.3.1]nonadiene diisocyanate and diacid dichloride

• Gert Kollenz,
• Ralf Smounig,
• Ferdinand Belaj,
• David Kvaskoff and
• Curt Wentrup

Beilstein J. Org. Chem. 2015, 11, 1–8, doi:10.3762/bjoc.11.1

• ability to extract some alkali, alkaline earth and rare earth metal ions. Keywords: carbamates; crown ethers; diisocyanate; isocyanate; ureas; Introduction The synthesis of the surprisingly stable, monomeric diisocyanate 1 (Figure 1) was reported recently [1]. This and several other derivatives of the

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

• Alan M. Jones and
• Craig E. Banks

Beilstein J. Org. Chem. 2014, 10, 3056–3072, doi:10.3762/bjoc.10.323

• electrolysis of carbamates to accumulate the N-acyliminium ion reactive intermediate then under non-oxidative conditions the nucleophile is introduced. Importantly, the nucleophile cannot be present when the N-acyliminium ion is being formed under electrochemical conditions, as in most cases it is easier to

• oxidise the nucleophile than the amide precursor. This circumvents the need to prepare, trap and release the N-acyliminium cation under more favourable conditions, allowing the direct α-alkylation or arylation of carbamates (Scheme 3); the cation pool method has been extensively studied [17][18][19][20

• ][21][22][23][24][25][26][27][28][29][30][31]. The use of electroauxiliaries The concept of electroauxiliaries has proven useful for developing and expanding the scope of the Shono-type oxidation of carbamates; electroauxiliaries activate organic compounds towards electron transfer controlling the fate

Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

• Roman Matthessen,
• Jan Fransaer,
• Koen Binnemans and
• Dirk E. De Vos

Beilstein J. Org. Chem. 2014, 10, 2484–2500, doi:10.3762/bjoc.10.260

• temperatures and pressures to activate CO2 [2][3]. Efficient chemical incorporation of CO2 is limited to rather reactive substrates, like epoxides [4][5][6] and amines [7][8][9] to produce cyclic carbonates and carbamates, respectively, and even then, elevated reaction temperatures and/or complex catalyst

Expanding the scope of cyclopropene reporters for the detection of metabolically engineered glycoproteins by Diels–Alder reactions

• Anne-Katrin Späte,
• Verena F. Schart,
• Julia Häfner,
• Andrea Niederwieser,
• Thomas U. Mayer and
• Valentin Wittmann

Beilstein J. Org. Chem. 2014, 10, 2235–2242, doi:10.3762/bjoc.10.232

• sugars 1 and 2 we neutralized the corresponding hexosamine hydrochlorides 5 and 6 with sodium methoxide and coupled them to the activated cyclopropene 7 (Scheme 2), the synthesis of which we reported previously [24]. Subsequent acetylation of the carbamates 8 and 9 gave Ac4GlcNCyoc (1) and Ac4GalNCyoc (2

Efficient CO₂ capture by tertiary amine-functionalized ionic liquids through Li⁺-stabilized zwitterionic adduct formation

• Zhen-Zhen Yang and
• Liang-Nian He

Beilstein J. Org. Chem. 2014, 10, 1959–1966, doi:10.3762/bjoc.10.204

• in the respective carbamates (onium salts) [39]. As previously reported, strong amidine and guanidine bases such as 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) can form the base-CO2 zwitterionic adduct in a 1:1 manner under strictly anhydrous conditions (Scheme 1c) [40][41]. Herein, we present such a

A promising cellulose-based polyzwitterion with pH-sensitive charges

• Thomas Elschner and
• Thomas Heinze

Beilstein J. Org. Chem. 2014, 10, 1549–1556, doi:10.3762/bjoc.10.159

• in vacuum at room temperature, dissolved in 10 mL water, dialyzed against deionized water, and finally lyophilized. Yield: 71% Reaction scheme of the synthesis of anionic, cationic, and ampholytic cellulose carbamates (substituents randomly distributed). 13C NMR spectra of (3-ethoxy-3-oxopropyl)(N

Amino acid motifs in natural products: synthesis of O-acylated derivatives of (2S,3S)-3-hydroxyleucine

• Oliver Ries,
• Martin Büschleb,
• Markus Granitzka,
• Dietmar Stalke and
• Christian Ducho

Beilstein J. Org. Chem. 2014, 10, 1135–1142, doi:10.3762/bjoc.10.113

• analogues, we were in need for a more versatile protecting group pattern. We therefore investigated different carbamates as protecting groups for the amino functionality, leading to the secondary alcohol functionality being selectively accessible for further conversions. We discovered that we were in need

Synthesis of fluorescent (benzyloxycarbonylamino)(aryl)methylphosphonates

• Michał Górny vel Górniak,
• Anna Czernicka,
• Piotr Młynarz,
• Waldemar Balcerzak and
• Paweł Kafarski

Beilstein J. Org. Chem. 2014, 10, 741–745, doi:10.3762/bjoc.10.68

• aldehydes and benzyl carbamates (the so called Oleksyszyn reaction) for the synthesis of fluorescent (benzyloxycarbonylamino)(aryl)methylphosphonates. Results and Discussion Synthesis of diaryl (benzyloxycarbonylamino)(phenyl)methylphosphonates Diaryl esters of Z-protected aminobenzylphosphonic acid were

Concise, stereodivergent and highly stereoselective synthesis of cis- and trans-2-substituted 3-hydroxypiperidines – development of a phosphite-driven cyclodehydration

• Peter H. Huy,
• Julia C. Westphal and
• Ari M. P. Koskinen

Beilstein J. Org. Chem. 2014, 10, 369–383, doi:10.3762/bjoc.10.35

• aspartic acid mono ester was obtained in a 5:1 ratio with the diester (not shown) after approximately 18 h of reaction time. Shorter reaction times in the esterification step of 1f decreased the yield of 8f. The amines 8e and 8f were converted in a straightforward manner to the carbamates 2e and 2f under