A semisynthesis of 3'-O-ethyl-5,6-dihydrospinosyn J based on the spinosyn A aglycone

• Kai Zhang,
• Shenglan Liu,
• Anjun Liu,
• Hongxin Chai,
• Jiarong Li and
• Lamusi A

Beilstein J. Org. Chem. 2017, 13, 2603–2609, doi:10.3762/bjoc.13.257

• ethylate the hydroxy group at 3-position of rhamnose. The structure of 2 was also ascertained by NMR. Then compound 2 was methylated at 0 °C in the presence of iodomethane and sodium hydride to afford 3. Finally, 3-O-ethyl-2,4-di-O-methylrhamnose (4) was obtained by the deprotection of 3 with Pd(PPh3)4 as

A permutation approach to the assignment of the configuration to diastereomeric tetrads by comparison of experimental and ab initio calculated differences in NMR data

• Przemysław J. Boratyński

Beilstein J. Org. Chem. 2017, 13, 2478–2485, doi:10.3762/bjoc.13.245

• , 132.1, 128.0, 122.25, 122.20, 119.9, 114.9, 100.4, 61.4, 57.4, 56.0, 55.8, 41.5, 39.5, 27.7, 27.2, 25.2 ppm; HRMS–ESI–TOF (m/z): [M + H]+ calcd for C22H26N5O, 376.2132; found, 376.2141. 9R-Phenyl-9-deoxyquinine (2b): Under inert gas (Ar), a sodium hydride dispersion (60% in mineral oil, 195 mg, 4.9 mmol

An efficient synthesis of a C₁₂-higher sugar aminoalditol

• Łukasz Szyszka,
• Anna Osuch-Kwiatkowska,
• Mykhaylo A. Potopnyk and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2017, 13, 2146–2152, doi:10.3762/bjoc.13.213

• , 6.72; N, 0.88. To a stirred solution of 8 (0.35 g, 0.21 mmol) in DMF (20 mL) containing imidazole (1.5 mg), sodium hydride (60% dispersion in mineral oil, 80.6 mg, 2.1 mmol) was added, and the mixture was stirred at 20 °C for 30 min. Benzyl bromide (0.2 mL, 1.68 mmol) was added dropwise and the mixture

Synthesis of substituted Z-styrenes by Hiyama-type coupling of oxasilacycloalkenes: application to the synthesis of a 1-benzoxocane

• James R. Vyvyan,
• Courtney A. Engles,
• Scott L. Bray,
• Erik D. Wold,
• Christopher L. Porter and
• Mikhail O. Konev

Beilstein J. Org. Chem. 2017, 13, 2122–2127, doi:10.3762/bjoc.13.209

• ether 24 along with debrominated 25 as the major product (Table 2, entry 4). As before, irreversibly deprotonating the alcohol with sodium hydride was not productive (Table 2, entry 5). Using Pd2(dba)3 as catalyst precursor increased the yield of 24 relative to the amount of 25 produced, but the overall

Synthesis of benzannelated sultams by intramolecular Pd-catalyzed arylation of tertiary sulfonamides

• Valentin A. Rassadin,
• Mirko Scholz,
• Anastasiia A. Klochkova,
• Armin de Meijere and
• Victor V. Sokolov

Beilstein J. Org. Chem. 2017, 13, 1932–1939, doi:10.3762/bjoc.13.187

• contained a certain amount of water, so that the benzoates 10d,e underwent hydrolysis. Indeed, when the sultam 10e was treated with sodium hydride in freshly distilled dioxane followed by addition of a small amount of water, the acid 10h was isolated in an excellent yield of 93%. The relative stability of

• precursor 20 was prepared in one step from the respective sulfonamide 19 and 2-iodobenzyl alcohol employing a Mitsunobu protocol (Scheme 6) [49]. Treatment of 20 with palladium acetate, Ph3P, and sodium hydride in dioxane at 90 °С for 20 h furnished the target sultam 21 in 49% yield. Apparently, the

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

Sugar-based micro/mesoporous hypercross-linked polymers with in situ embedded silver nanoparticles for catalytic reduction

• Qing Yin,
• Qi Chen,
• Li-Can Lu and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 1212–1221, doi:10.3762/bjoc.13.120

• -linker, the Friedel–Crafts cross-linking polymerization is promoted smoothly by anhydrous FeCl3 in dry 1,2-dichloroethane (DCE). The monomers were either commercially available (Sug-1) or prepared (Sug-2 and Sug-3) by benzylation of free sugars with benzyl bromide and sodium hydride. The chemical

• precursors for the preparation of pharmaceuticals and agrochemicals. Experimental Synthesis of perbenzyl phenyl β-D-glucopyranoside (Sug-2) Sodium hydride (60%, 0.43 g, 10.85 mmol) was added portionwise to a solution of phenyl β-D-glucopyranoside (93 mg, 0.36 mmol) in DMF (5.0 mL) over 40 min under nitrogen

• –TOF) m/z: [M + Na] calcd for C40H40O6, 639.3; found: 639.4. Synthesis of perbenzyl methyl α-L-rhamnopyranoside (Sug-3) Sodium hydride (160 mg, 60%, 6.72 mmol) was added to a solution of methyl α-L-rhamnopyranoside (200 mg, 1.12 mmol) in DMF (5.0 mL) in an ice bath over 40 min under a nitrogen

Total syntheses of the archazolids: an emerging class of novel anticancer drugs

• Stephan Scheeff and
• Dirk Menche

Beilstein J. Org. Chem. 2017, 13, 1085–1098, doi:10.3762/bjoc.13.108

• efforts had to be invested, before acid 21 could be efficiently obtained as shown in Scheme 4. Finally, after optimization of a reported procedure [73] the successful route employed a one-pot process involving a sodium hydride-mediated coupling of methyl malonate 19 with iodoform (20) followed by a

Structure–efficiency relationships of cyclodextrin scavengers in the hydrolytic degradation of organophosphorus compounds

• Sophie Letort,
• Michaël Bosco,
• Benedetta Cornelio,
• Frédérique Brégier,
• Sébastien Daulon,
• Géraldine Gouhier and
• François Estour

Beilstein J. Org. Chem. 2017, 13, 417–427, doi:10.3762/bjoc.13.45

• third methylene group. The monosubstituted derivative 18 was prepared in good yield by reaction of the tritylated imidazole 7 with monohydroxy compound 17 in the presence of sodium hydride (Scheme 3) [35]. The 1H NMR signals of the diastereotopic methylene protons in product 18 were respectively

The reductive decyanation reaction: an overview and recent developments

• Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

• ether cleavage. Aluminium- and borohydrides and the use of sodium hydride Reduction of α-aminonitriles Bifunctional α-aminonitriles exhibit several modes of reactivity. Recent reviews demonstrated the richness of this chemistry and emphasized synthetic applications particularly in heterocyclic chemistry

• -withdrawing group. Synthesis of (±)-isoretronecanol 19. DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene [74]. Proposed mechanism with 14a for the NaBH4 induced decyanation reaction (“BH3” = BH3·THF) [74]. Reductive decyanation by a sodium hydride–iodide composite (26 examples) [81]. Proposed mechanism for the

Efficient mechanochemical synthesis of regioselective persubstituted cyclodextrins

• Laszlo Jicsinszky,
• Marina Caporaso,
• Katia Martina,
• Emanuela Calcio Gaudino and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2016, 12, 2364–2371, doi:10.3762/bjoc.12.230

• as sodium hydride, to activate the thiol group of 3-mercaptopropionic acid (MPA) and N,N-dimethylformamide (DMF) [16]. In the reaction solution and particularly on larger scales (from 10 g to kilo lab scale), impurities that arise from incomplete conversions, product and byproduct decomposition as

• stage, the sodium salt of octakis(6-deoxy-6-S-(3-mercapto)propionyl)-γ-CD has been slowly becoming an important surgical aid. The solution phase reaction is a dangerous process due to the use of sodium hydride. The relatively large number of possible side-reactions in solution brings further challenges

Synthesis and characterization of fluorinated azadipyrromethene complexes as acceptors for organic photovoltaics

• Forrest S. Etheridge,
• Roshan J. Fernando,
• Sandra Pejić,
• Matthias Zeller and
• Geneviève Sauvé

Beilstein J. Org. Chem. 2016, 12, 1925–1938, doi:10.3762/bjoc.12.182

• using Zn(OAc)2 to a 2-step, one pot reaction with sodium hydride in tetrahydrofuran, followed by the addition of zinc(II) chloride. Zinc(II) and BF2+ chelates were purified by silica gel column chromatography to isolate the chelates as blue solids and the identity and purity was confirmed by NMR

Three-component synthesis of highly functionalized aziridines containing a peptide side chain and their one-step transformation into β-functionalized α-ketoamides

• Lena Huck,
• Juan F. González,
• Elena de la Cuesta and
• J. Carlos Menéndez

Beilstein J. Org. Chem. 2016, 12, 1772–1777, doi:10.3762/bjoc.12.166

• dioxane followed by the addition of 1.2 equivalents of a primary or secondary amine or alcohol in the presence of 2 equivalents of sodium hydride afforded the highly substituted and functionalized aziridine derivatives 2. Under these conditions, it can be assumed that methoxide is the predominant base

• with butylamine and sodium hydride under our standard conditions, compound 2c was isolated in 85% yield. With compounds 2 in hand, we next examined their transformation into β-amino-α-ketoamide derivatives. While the synthetic applications of aziridines have received much attention [11][25][26][27][28

Towards potential nanoparticle contrast agents: Synthesis of new functionalized PEG bisphosphonates

• Souad Kachbi-Khelfallah,
• Maelle Monteil,
• Margery Cortes-Clerget,
• Evelyne Migianu-Griffoni,
• Jean-Luc Pirat,
• Olivier Gager,
• Julia Deschamp and
• Marc Lecouvey

Beilstein J. Org. Chem. 2016, 12, 1366–1371, doi:10.3762/bjoc.12.130

• commercially available. Firstly, the free alcohol PEG was selectively monoprotected with a benzyl group (Scheme 3). Only one alcohol function was indeed deprotonated with one equivalent of sodium hydride at −78 °C in THF after the solution was stirred for 12 hours at room temperature. The alcoholate

• a free alcohol four-unit PEG. It reacted with ethyl bromoacetate after mono-deprotonation using sodium hydride in THF at −78 °C for 12 hours at room temperature giving PEG 18. HMBP-PEG 22 was next synthesized in four steps with satisfying yields in a similar strategy previously described for

Synthesis of highly functionalized 2,2'-bipyridines by cyclocondensation of β-ketoenamides – scope and limitations

• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2016, 12, 1170–1177, doi:10.3762/bjoc.12.112

• of the cyclocondensation step and subjected the unpurified compounds to the O-nonaflation procedure. Treatment with an excess of sodium hydride in THF followed by reaction with nonafluorobutanesulfonyl fluoride (NfF) afforded the desired 2,2´-bipyridine derivatives 5a–g containing the 4-nonafloxy

Chiral cyclopentadienylruthenium sulfoxide catalysts for asymmetric redox bicycloisomerization

• Barry M. Trost,
• Michael C. Ryan and
• Meera Rao

Beilstein J. Org. Chem. 2016, 12, 1136–1152, doi:10.3762/bjoc.12.110

• bicycloisomerization reaction can be readily accessed in two steps. Alkylation of a secondary propargylamide can be achieved by sodium hydride deprotonation of its acidic proton and SN2 substitution of a substituted propargyl bromide (Scheme 5a). Alternatively, the same propargylamide can be alkylated under Mitsunobu

Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate

• Sean P. Bew,
• Glyn D. Hiatt-Gipson,
• Graham P. Mills and
• Claire E. Reeves

Beilstein J. Org. Chem. 2016, 12, 1081–1095, doi:10.3762/bjoc.12.103

• phosphoacetate with sodium hydride. A separable mixture of (E)-64 and (Z)-65 (1.35:1) was afforded in an overall 61% yield from 62. DIBAL-H readily reduced the ethyl ester on (E)-64 and (Z)-65 (−78 °C, toluene) affording 1° alcohols (E)-66 and (Z)-67 in 97% and 95% yields, respectively. Increasing the

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• corresponding halide in the presence of sodium hydride, giving thus access to thioether derivatives of type 68, which can also be converted into γ-lactams such as 69. On the other hand, experiments carried out with pyridyl and quinoylthiazolone substrates reveal that in these cases selectivity is higher than

Synthesis and nucleophilic aromatic substitution of 3-fluoro-5-nitro-1-(pentafluorosulfanyl)benzene

• Javier Ajenjo,
• Martin Greenhall,
• Camillo Zarantonello and
• Petr Beier

Beilstein J. Org. Chem. 2016, 12, 192–197, doi:10.3762/bjoc.12.21

• -boiling alcohols (MeOH, EtOH), the reactions were heated under reflux using the alcohol as a solvent and excess of potassium hydroxide (Table 1, entries 1 and 2). For alcohols with higher boiling points, the reactions were performed with sodium hydride (Table 1, entries 3 and 4). For phenol, thiophenol

Synthesis of Xenia diterpenoids and related metabolites isolated from marine organisms

• Tatjana Huber,
• Lara Weisheit and
• Thomas Magauer

Beilstein J. Org. Chem. 2015, 11, 2521–2539, doi:10.3762/bjoc.11.273

• isobutene (36), an isomeric mixture of trans- and cis-fused [4.2.0]octanone was obtained (trans-38/cis-39 = 4:1). The more stable cis-bicycle 39 could be obtained by isomerization of trans-38 with base. Acylation with sodium hydride and dimethyl carbonate followed by methylation furnished β-keto ester 40

Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• RRM approach. In this regard, secondary alcohol derivatives related to 8-oxabicyclo[3.2.1]octenes such as 341a,b,c were used as potential precursors for the synthesis of a variety of cyclic polyethers [71]. Allylation of 340a–c using sodium hydride and allyl bromide (37) in the presence of a phase

Pyridinoacridine alkaloids of marine origin: NMR and MS spectral data, synthesis, biosynthesis and biological activity

• Louis P. Sandjo,
• Victor Kuete and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2015, 11, 1667–1699, doi:10.3762/bjoc.11.183

• conditions. The bipyridine derivative obtained was subjected to a strong base (sodium hydride) to give 12-deoxyascididemin which was immediately oxidized in situ by oxygen to yield ascididemin (42, Scheme 6) [65]. Synthesis of subarine (37) Method A: This alkaloid was successfully prepared in five steps with

Development of variously functionalized nitrile oxides

• Haruyasu Asahara,
• Keita Arikiyo and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2015, 11, 1241–1245, doi:10.3762/bjoc.11.138

• -dimethylbenzamide (6A) and sodium hydride (2 equiv) in THF, mesyl chloride (7a, 1.3 equiv) was added, and the resultant mixture was stirred at room temperature for 9 h. After acidification, the reaction mixture was extracted with diethyl ether to afford the crude material, from which 32% of N-mesylated product 8Aa

• [11] was isolated and 61% of 6A was recovered. Thus, the conversion yield of 8Aa was 82% (Table 1, entry 1). On the other hand, the yield of 8Aa was considerably increased (up to 70%) when ethylmagnesium bromide was employed as a base instead of sodium hydride (Table 1, entry 2). However, the

• to the aliphatic amide N-methylcyclohexanecarboxamide (6B) to afford 8Bb upon treatment with tosyl chloride (7b) using sodium hydride as a base (Table 1, entry 4). In this case, the use of an excess of 7b increased the yield of 8Bb up to 60% (85% of conversion yield, Table 1, entry 5). Next

Synthesis of carbohydrate-scaffolded thymine glycoconjugates to organize multivalency

• Anna K. Ciuk and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2015, 11, 668–674, doi:10.3762/bjoc.11.75

• . Figure 1B). Based on our earlier work [5], we first planned to employ an appropriate bromoalkyl mannoside for N-alkylation of the thymine N3 [28]. In this step, DBU can be employed as non-nucleophilic base [29] leaving the NHBoc group intact. When sodium hydride is employed instead, NHBoc is deprotonated

Attempts to prepare an all-carbon indigoid system

• Şeref Yildizhan,
• Henning Hopf and
• Peter G. Jones

Beilstein J. Org. Chem. 2015, 11, 363–372, doi:10.3762/bjoc.11.42

• interactions. Our next approach towards 4 (or a derivative) started from indan-1-one (18, Scheme 4). Enolization of 18 was carried out with sodium hydride in THF and on subsequent oxidative dimerization the expected bis-ketone 19 was obtained. This compound is produced as a mixture of two diastereomers in

• roughly 1:1 ratio (NMR analysis), which can be separated by column chromatography. Since, however, in the next step the connecting single bond is transformed into a double bond, we used the diastereomeric mixture for the subsequent oxidation. This was carried out by metalating 19 with sodium hydride again