Total synthesis of ochnaflavone

• Monica M. Ndoile and
• Fanie R. van Heerden

Beilstein J. Org. Chem. 2013, 9, 1346–1351, doi:10.3762/bjoc.9.152

• formation of the chalcone by an aldol condensation reaction with a suitably substituted acetophenone. Selective methylation of 2,4,6-trihydroxyacetophenone with methyl iodide yielded 2'-hydroxy-4',6'-dimethoxyacetophenone (5) in moderate yield. The Claisen–Schmidt condensation of 5 with diaryl ether 4 under

• , 129.5, 122.3, 116.3 (2C), 113.4, 55.9; HRMS–ESI (positive-ionization mode): m/z 279.0625 [M + Na]+ (calculated for C15H12O4Na, 279.0633). 2'-Hydroxy-4',6'-dimethoxyacetophenone (5) [33]: To a well-stirred mixture of 2',4',6'-trihydroxyacetophenone (500 mg, 2.97 mmol) and methyl iodide (1.06 g, 7.47 mmol

Synthesis of guanidinium–sulfonimide ion pairs: towards novel ionic liquid crystals

• Martin Butschies,
• Manuel M. Neidhardt,
• Markus Mansueto,
• Sabine Laschat and
• Stefan Tussetschläger

Beilstein J. Org. Chem. 2013, 9, 1093–1101, doi:10.3762/bjoc.9.121

• ; ESIMS (m/z): 418 [M]−, 340 [M− − CH3O2S + H], 249 [M− − C12H25]; HRMS–ESI (m/z): [M]− calcd for C19H32NO5S2–, 418.1727; found, 418.1728. General procedure for the preparation of pentamethylguanidinium ion pairs (2a,b) Potassium carbonate (144 mg, 971 μmol) and methyl iodide (207 mg, 1.46 mmol) were

Amyloid-β probes: Review of structure–activity and brain-kinetics relationships

• Todd J. Eckroat,
• Abdelrahman S. Mayhoub and
• Sylvie Garneau-Tsodikova

Beilstein J. Org. Chem. 2013, 9, 1012–1044, doi:10.3762/bjoc.9.116

• : BTA = 2-(4'-methylaminophenyl)benzothiazole, Figure 2), was prepared by methylation of 4-(6-methyl-2-benzothiazolyl)aniline using [11C]methyl iodide [49]. Compared to 4, 56a showed greatly increased lipophilicity and improved binding affinity for Aβ1-40 (Ki = 890 nM for 4 and Ki = 20.2 for 56a). In

• group gave [11C]BTA-1 ([11C]56b) [50]. Compound 56b was prepared by coupling of p-nitrobenzoyl chloride (35) and 2-aminothiophenol (66) followed by nitro reduction to 67 and methylation using [11C]methyl iodide (Scheme 6A). While showing a near equal binding affinity for Aβ, the decreased lipophilicity

• , methylation using [11C]methyl iodide, and cleavage of the MOM ether gave [11C]56c. Compound 56c showed high affinity for Aβ1-40 (Ki = 4.3 nM) (Table 5). This synthesis has since been refined to improve radiochemical yields and eliminate the need for a protecting group by use of [11C]CH3OTf as the methylating

Efficient Cu-catalyzed base-free C–S coupling under conventional and microwave heating. A simple access to S-heterocycles and sulfides

• Silvia M. Soria-Castro and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2013, 9, 467–475, doi:10.3762/bjoc.9.50

• substitution reactions with methyl iodide and benzyl bromide, methyl phenyl sulfide and benzyl methyl sulfide in 81% and 66% yields, respectively, and 4-anisyl phenyl sulfide (4-AnSPh) in 85% yield (quantified by 1H NMR) by a second copper-catalyzed reaction (Scheme 8). Conclusion We have developed a simple

Polar reactions of acyclic conjugated bisallenes

• Reiner Stamm and
• Henning Hopf

Beilstein J. Org. Chem. 2013, 9, 36–48, doi:10.3762/bjoc.9.5

• and quenching of 4 with simple halides Treating 2 in THF at −30 °C with a slight excess of n-butyllithium (1.2 equiv) in the presence of tetramethylethylendiamine (TMEDA) and quenching the formed monoanion 4 with methyl iodide in THF results in the formation of 2,4,7-trimethylocta-2,3,5,6-tetraene (5

Intramolecular carbolithiation of N-allyl-ynamides: an efficient entry to 1,4-dihydropyridines and pyridines – application to a formal synthesis of sarizotan

• Wafa Gati,
• Mohamed M. Rammah,
• Mohamed B. Rammah and
• Gwilherm Evano

Beilstein J. Org. Chem. 2012, 8, 2214–2222, doi:10.3762/bjoc.8.250

• the activated alkyne, we first reacted N-benzyl-ynamide 7 with one equivalent of sec-butyllithium and tetramethylethylenediamine (TMEDA) in THF at −78 °C for 15 minutes, followed by the addition of methyl iodide. The corresponding N-phenylethyl-ynamide 8 was obtained in nearly quantitative yield

• , therefore demonstrating the compatibility of the ynamide group with the deprotonation step (Scheme 2a), although longer reaction times before the addition of methyl iodide resulted in much lower yields and extensive degradation: The intramolecular carbolithiation of N-allyl-ynamides to 1,4-dihydropyridines

• . N-Allyl-ynamide 1a was therefore cyclized under our standard conditions and then treated with deuterated water (Scheme 5a) or methyl iodide (Scheme 5b) before the acidic and oxidative workup. While the desired 2,3-disubstituted 6s and 6t were indeed formed under these conditions, they could only be

Regioselective synthesis of 7,8-dihydroimidazo[5,1-c][1,2,4]triazine-3,6(2H,4H)-dione derivatives: A new drug-like heterocyclic scaffold

• Nikolay T. Tzvetkov,
• Harald Euler and
• Christa E. Müller

Beilstein J. Org. Chem. 2012, 8, 1584–1593, doi:10.3762/bjoc.8.181

• multigram scale. Finally, the imidazotriazines were further functionalized by an N-alkylation reaction using different alkylating reagents under basic conditions (Scheme 3). Alkylation of 24 with methyl iodide led to 26, whereas methyl methanesufonate was used as an alkylating reagent for the methylation of

Metal–ligand multiple bonds as frustrated Lewis pairs for C–H functionalization

• Matthew T. Whited

Beilstein J. Org. Chem. 2012, 8, 1554–1563, doi:10.3762/bjoc.8.177

• Fryzuk [62][63][64]. With a coordinatively unsaturated and electron-rich center, this species exhibits some reactivity that is similar to the isoelectronic Vaska's complex [65], such as oxidative addition of methyl iodide. It also reacts in dipolar fashion with an in-situ-generated phosphorus ylide to

Synthesis of 4” manipulated Lewis X trisaccharide analogues

• Christopher J. Moore and
• France-Isabelle Auzanneau

Beilstein J. Org. Chem. 2012, 8, 1134–1143, doi:10.3762/bjoc.8.126

• conditions the α-tripivaloate 15, selectively acylated at O-2, O-3 and O-6, was obtained pure and free of β-anomer (64%). The free hydroxy group in alcohol 15 was then deprotonated with sodium hydride and allowed to react with methyl iodide, yielding the 4-OMe galactoside 16 in very good yield. In turn

Recent advances towards azobenzene-based light-driven real-time information-transmitting materials

• Jaume García-Amorós and
• Dolores Velasco

Beilstein J. Org. Chem. 2012, 8, 1003–1017, doi:10.3762/bjoc.8.113

• -dyes 8 and 9 at 298 K. The relaxation times for cis-8 and cis-9 are 2.8 ms and 570 µs, respectively (Figure 9). Figure 10 depicts the proposed mechanism for the thermally-activated cis-to-trans isomerisation of the cis isomers of the push–pull azopyridinium methyl iodide salts 8 and 9. The strong

• section. Type-III azoderivatives: optical switches acting within the microsecond time scale, based on azo-dyes exhibiting both azo-hydrazone tautomerism and a push–pull electronic distribution Among all the azoderivatives presented up to now in this review, azopyridinium methyl iodide salts are the

• final photodriven oscillator. Methylation of the pyridine nitrogen of azo-dyes 22 and 23 was carried out to afford the corresponding pyridinium methyl iodide salts 26 and 27. Thus, the methyl hydroxy-substituted azopyridinium salts 26 and 27 present relaxation times of only 150 µs and 33 µs

Diarylethene-modified nucleotides for switching optical properties in DNA

• Sebastian Barrois and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2012, 8, 905–914, doi:10.3762/bjoc.8.103

• ) is based on Sonogashira-type cross couplings as key steps [51] to attach the photoactive chromophore to the nucleoside. For the synthesis of the first nucleoside 4 (Scheme 2), commercially available 5-bromobenzothiazole (7) is deprotonated with LDA and methylated by methyl iodide in quantitative

meta-Oligoazobiphenyls – synthesis via site-selective Mills reaction and photochemical properties

• Raphael Reuter and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2012, 8, 877–883, doi:10.3762/bjoc.8.99

• %. The next two steps in the synthesis of the building blocks were straightforward (Scheme 2) and comprised esterification of the acid 6 with potassium carbonate and methyl iodide in acetone, as well as reduction of the nitro group via a Béchamp reaction to give compound 9. The amino group was afterwards

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• rim is also possible, as shown by Araki in 2000, through a complex synthetic pathway starting from bromooxacalix[3]arene [51]. As shown in Scheme 19, oxacalix[3]arene 3f was treated with methyl iodide in the presence of NaH in THF at reflux to afford its methyl ether 41 in 41% yield. With the lower

A practical two-step procedure for the preparation of enantiopure pyridines: Multicomponent reactions of alkoxyallenes, nitriles and carboxylic acids followed by a cyclocondensation reaction

• Christian Eidamshaus,
• Roopender Kumar,
• Mrinal K. Bera and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2011, 7, 962–975, doi:10.3762/bjoc.7.108

• 22 could be O-methylated in good yield with methyl iodide in THF, the same conditions converted 30 into 55 in a disappointing 30% yield. Desilylation of 53 and 55 with HF in pyridine gave the desired deprotected pyridine derivatives 54 and 56 in high yields. This type of enantiopure hydroxymethyl

Synthesis of chiral mono(N-heterocyclic carbene) palladium and gold complexes with a 1,1'-biphenyl scaffold and their applications in catalysis

• Lian-jun Liu,
• Feijun Wang,
• Wenfeng Wang,
• Mei-xin Zhao and
• Min Shi

Beilstein J. Org. Chem. 2011, 7, 555–564, doi:10.3762/bjoc.7.64

• heating with methyl iodide in acetonitrile provided the corresponding benzimidazolium salt (S)-5a in quantitative yield. With the NHC precursor (S)-5a in hand, its coordination with Pd or Au metal salts was examined. Benzimidazolium salt (S)-5a was treated with (η3-C3H5PdCl)2 in tetrahydrofuran (THF) in

• (S)-8 in 98% yield. Amine (S)-8 was then treated with (Boc)2O in the presence of Et3N at room temperature for 24 h to give the corresponding BOC derivative (S)-4b in 87% yield. Quaternization of the benzimidazole ring of (S)-4b with methyl iodide in acetonitrile gave the corresponding benzimidazolium

An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals

• Marcus Baumann,
• Ian R. Baxendale,
• Steven V. Ley and
• Nikzad Nikbin

Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57

• group unmasks the aniline which undergoes nucleophilic aromatic substitution to introduce the pyrimidine system with the formation of 253. Methylation of the secondary amine function with methyl iodide prior to a second SNAr reaction with a sulfonamide-derived aniline affords pazopanib (Scheme 50) [76

Approaches towards the synthesis of 5-aminopyrazoles

• Ranjana Aggarwal,
• Vinod Kumar,
• Rajiv Kumar and
• Shiv P. Singh

Beilstein J. Org. Chem. 2011, 7, 179–197, doi:10.3762/bjoc.7.25

• temperature, followed by treatment with methyl iodide afforded the novel ketene N,S-acetal 149. Reaction of 149 with hydrazine in refluxing ethanol gave the corresponding 5-aminopyrazole derivative 150. The reaction proceeds in the usual manner, i.e., loss of methylthio group by nucleophilic attack of

Photocycloaddition of aromatic and aliphatic aldehydes to isoxazoles: Cycloaddition reactivity and stability studies

• Axel G. Griesbeck,
• Marco Franke,
• Jörg Neudörfl and
• Hidehiro Kotaka

Beilstein J. Org. Chem. 2011, 7, 127–134, doi:10.3762/bjoc.7.18

• carbonate (38.70 g, 0.28 mol) and methyl iodide (49.68 g, 0.35 mol, 21.8 mL) in acetone (200 mL) was refluxed in the dark for 20 h and then cooled to rt. The insoluble material was removed by filtration and washed thoroughly with acetone. The combined filtrate and acetone washings were then concentrated

Pyridinium based amphiphilic hydrogelators as potential antibacterial agents

• Sayanti Brahmachari,
• Sisir Debnath,
• Sounak Dutta and
• Prasanta Kumar Das

Beilstein J. Org. Chem. 2010, 6, 859–868, doi:10.3762/bjoc.6.101

• , India. Thionyl chloride, 3-aminopyridine, methyl iodide were purchased from Spectrochem, India. D2O, DMSO-d6 and CDCl3 were obtained from Aldrich Chemical Co. Thin layer chromatography was performed on Merck pre-coated silica gel 60-F254 plates. All the material used in the cell culture study, such as

• brine until neutral. The ethyl acetate was then removed and the alkylated compound coupled through the amide linkage purified by column chromatography on 60–120 mesh silica gel with 1% methanol/chloroform mixture as eluent (75% yield). The compound thus obtained was stirred with methyl iodide (1.1 equiv

Recent advances in carbocupration of α-heterosubstituted alkynes

• Ahmad Basheer and
• Ilan Marek

Beilstein J. Org. Chem. 2010, 6, No. 77, doi:10.3762/bjoc.6.77

• carbometalation of 1-alkynylphosphines with magnesium dibutylcuprate (Bu2CuMgBr) leads to diphenyl(butylethynyl)phosphine in good isolated yields [29][30]. The addition of various electrophiles (with the exception of aldehydes and methyl iodide) such as allylbromide, benzoyl chloride) was successful (Scheme 14

Synthesis of a novel analogue of DPP-4 inhibitor Alogliptin: Introduction of a spirocyclic moiety on the piperidine ring

• Arumugam Kodimuthali,
• Padala Lakshmi Prasunamba and
• Manojit Pal

Beilstein J. Org. Chem. 2010, 6, No. 71, doi:10.3762/bjoc.6.71

• our attention on the other intermediate 11, the preparation of which has been previously documented [23]. The reaction of commercially available 6-chlorouracil with 2-(bromomethyl)benzonitrile in the presence of NaH afforded the N-alkylated product 10 which on methylation with methyl iodide provided

Ring opening metathesis polymerization-derived block copolymers bearing chelating ligands: synthesis, metal immobilization and use in hydroformylation under micellar conditions

• Gajanan M. Pawar,
• Jochen Weckesser,
• Siegfried Blechert and
• Michael R. Buchmeiser

Beilstein J. Org. Chem. 2010, 6, No. 28, doi:10.3762/bjoc.6.28

• was converted into M2 via quaternization of the tertiary amine with methyl iodide. Synthesis of homo- and block copolymers via ROMP [12][13] ROMP has already been used for the synthesis of micelle-forming block copolymers [14], however, the one used in this study, i.e. poly(M1-b-M2), required special

Bis(oxazolines) based on glycopyranosides – steric, configurational and conformational influences on stereoselectivity

• Tobias Minuth and
• Mike M. K. Boysen

Beilstein J. Org. Chem. 2010, 6, No. 23, doi:10.3762/bjoc.6.23

• phthalimido protected precursor 7 (Scheme 3). Introduction of the 3-xanthogenate with carbon disulfide and methyl iodide yielded 17, which was cleanly deoxygenated in high yield by tributyltin hydride under standard conditions [32][33]. From the resulting compound 18, the ligands 3-deoxy glucoBox 21 with

Dipyridodiazepinone derivatives; synthesis and anti HIV-1 activity

• Nisachon Khunnawutmanotham,
• Nitirat Chimnoi,
• Arunee Thitithanyanont,
• Patchreenart Saparpakorn,
• Kiattawee Choowongkomon,
• Pornpan Pungpo,
• Supa Hannongbua and
• Supanna Techasakul

Beilstein J. Org. Chem. 2009, 5, No. 36, doi:10.3762/bjoc.5.36

• -dimethylformamide yielded 2, 3, and 4, respectively, whilst the reaction of 23b with thiophenolate and 3-methoxythiophenolate yielded 5 and 6, respectively. Methylation of the lactam nitrogen of 5 and 6 with methyl iodide provided 7 and 8. Compound 9 was also prepared via methylation of 2, which was used as the

Convenient method for preparing benzyl ethers and esters using 2-benzyloxypyridine

• Susana S. Lopez and
• Gregory B. Dudley

Beilstein J. Org. Chem. 2008, 4, No. 44, doi:10.3762/bjoc.4.44

• the synthesis of benzyl ethers are equally relevant for the synthesis of halobenzyl ethers (3a → 7, 98% yield). Finally, replacement of methyl triflate with less reactive methylating reagents, including dimethyl sulfate (Me2SO4), methyl tosylate (MeOTs), and methyl iodide (MeI), did not provide

• comparable results. N-Methylation of 2-benzyloxypyridine with methyl triflate occurs at or below room temperature to furnish triflate salt 1 in a manner of minutes. In contrast, reaction of methyl iodide with 2-chloropyridine requires heating in acetone at reflux for 24 h [32] to provide Mukaiyama’s reagent