Presence Of N-iodosuccinimide Research Articles

α/β-Stereo- and diastereoselective glycosylation with n-pentenyl glycoside donors, promoted by N-iodosuccinimide and catalyzed by chiral Brønsted acid.

A method involving stereoselective glycosylation catalyzed by (+)-isomenthol ester of pentacarbomethoxycyclopentadiene as a chiral Brønsted acid, with n-pentenyl glycosides in the presence of N-iodosuccinimide as the promoter is described; this method offered a chiral recognition of racemic substrates.

A pentacarbomethoxycyclopentadiene (PCCP) organic Brønsted acid catalyzed stereoselective glycosidation of N-pentenyl orthoesters (NPOE) of d-glucose and d-galactose, in conjunction with N-iodosuccinimide

Herein, we report our preliminary results in utilizing the organic Brønsted acid, pentacarbomethoxycyclopentadiene (PCCP), for catalysing the glycosidation with n-pentenyl orthoesters (NPOE) of d-glucose and d-galactose in the presence of N-iodosuccinimide (NIS). Benzoyl and benzyl protection in d-glucosyl NPOEs led to 1,2-trans glycosides, while acetyl protection in NPOE led to a mixture of 1,2-cis and trans glycosides with >75% cis selectivity, and d-galactosyl NPOEs led to 1,2-orthoesters. Substrate scope was demonstrated with acceptors of natural product relevance. This article highlights the prospect of utilizing the organic Brønsted acid, PCCP, for stereoselective glycosidation.

Oxy- and aminoselenation of alkenes utilizing an isolable selenenyl iodide

Application of an isolable selenenyl iodide BpqSeI (Bpq denotes 5',5'''-bis(2,6-diisopropylphenyl)-2,6,2'''',6''''-tetra-isopropyl-1,1':3',1'':3'',1''':3''',1''''-quinquephenyl-2''-yl) to selenofunctionalization of alkenes with external oxygen or nitrogen nucleophiles was investigated. In the presence of N-iodosuccinimide as an additive, alcohols, a carboxylic acid, or aromatic amines were smoothly introduced to alkenes to give the corresponding β-oxy or β-amino selenides in moderate to high yields.

Synthesis and Antiproliferative Evaluation of 2-Deoxy-N-glycosylbenzotriazoles/imidazoles.

A series of 2-deoxy-2-iodo-α-d-mannopyranosylbenzotriazoles was synthesized using the benzyl, 4,6-benzylidene and acetyl protected D-glucal in the presence of N-iodosuccinimide (NIS). Subsequent removal of the iodine at the C-2 position using tributyltin hydride under free radical conditions afforded the 2-deoxy-α-d-glucopyranosylbenzotriazoles in moderate to high yields. This method was extended to the preparation of substituted 2-deoxy-β-d-glucopyranosylimidazoles as well. The stereoselectivity of the addition reaction and the effect of the protecting group and temperature on anomer distribution of the benzotriazole series were also investigated. The anticancer properties of the newly synthesized compounds were evaluated in a series of viability studies using HeLa (human cervical adenocarcinoma), human breast and lung cancer cell lines. The N-[3,4,6-tri-O-benzyl-2-deoxy-α-d-glucopyranosyl]-1H-benzotriazole and the N-[3,4,6-tri-O-acetyl-2-deoxy-α-d-glucopyranosyl]-2H-benzotriazole were found to be the most potent cancer cell inhibitors at 20 µM concentrations across all four cell lines.

Disulfide metathesis via sulfur⋯iodine interaction and photoswitchability.

The idea of constitutional dynamic chemistry (CDC) and dynamic combinatorial chemistry (DCC) is widespread in the literature using the chemistry of disulfides. The synthesis of unsymmetrical diaryl disulfides is challenging due to the presence of a weak S-S bond. We report herein the synthesis of unsymmetrical diaryl disulfides from two symmetrical disulfides via a cross-metathesis reaction which was controlled by a weak sulfur⋯iodine (S⋯I) interaction. The unsymmetrical disulfides were stable in acetonitrile solution in the presence of N-iodosuccinimide (NIS), and found to be reversibly photoswitchable to the symmetrical disulfides under visible light irradiation.

Comparative study of synthesis of cellulose propionate from different sources using NIS as a new catalyst

Propylation of cellulose from different sources with propionic anhydride using N-iodosuccinimide (NIS) under solvent-free condition was tested. It was done in the presence of NIS as a new catalyst for propylation using three different amounts of catalyst under mild reaction conditions. The degree of substitution by propionate was experimentally calculated and confirmed by FTIR and 1H NMR analyses. The propylation yields varied from 71.54 to 88.37% with the degree of substitution (DS) ranged from 1.32 to 2.80 for commercial cotton cellulose, 1.76–3.00 for rice husk cellulose, and 1.60–3.0 for wheat straw cellulose. The DS were easily controlled by changing the reaction duration (2–6 h) and the amount of the NIS catalyst (50, 75, and 100 mg for each 1.0 g of cellulose) in 25 mL of propionic anhydride. Prolonging the reaction’s duration has no favorable effect on the propylation process and led to decrease in the cellulose propionate (CP). Also, increasing the amount of NIS catalyst results in decrease the DS and CP yield. NIS was recognized as a novel and more successful catalyst for propylation of the hydroxyl groups of cellulose from different sources in high degree of substitution.

Synthesis and characterization of nitro-functionalized hydroxyl-terminated polybutadiene using N-iodosuccinimide

A convenient, inexpensive and highly efficient one-pot procedure of synthesizing nitro-functionalized hydroxyl-terminated polybutadiene (Nitro-HTPB) is reported by the reaction of hydroxyl-terminated polybutadiene (HTPB) and sodium nitrite in the presence of N-iodosuccinimide in EG–EtOAc–H2O at 60 °C for 24 h. The investigation of the effective parameters on the synthesis of Nitro-HTPB such as amounts of reactants, temperature and reaction time indicated that in the optimum reaction conditions, the nitration HTPB backbone is restricted to 6.7% of double bonds until the outstanding physical and chemical properties of HTPB are retained. The Nitro-HTPB was characterized by FTIR, 1H NMR, 13C NMR, DSC and TGA. The polymer showed good thermal stability, yield of 93%, viscosity of 14.2 Pa.s−1, number average molecular weight of 2730 gmol−1 and hydroxyl value of 34 mg KOH per g.

Umpolung Reactivity of in Situ Generated Phosphido-Boranes: An Entry to P-Stereogenic Aminophosphine-Boranes.

The synthesis of P-stereogenic aminophosphine-boranes has been developed on the basis of umpolung reactivity of in situ generated alkylarylphosphido-boranes, which are normally configurationally unstable intermediates. In our case, their high configurational stability was due to the slow release of the hydroxyalkyl protecting group, together with the fast formation of the iodophosphanylborane in the presence of N-iodosuccinimide. The subsequent substitution reaction was found to proceed in moderate to good yields and in a very high stereospecifity (es) using a variety of amines as nucleophiles.

Photoinduced cyclization of alkynoates to coumarins with N-Iodosuccinimide as a free-radical initiator under ambient and metal-free conditions

An efficient photoinduced strategy for the preparation of coumarins was developed. In the presence of N-iodosuccinimide (NIS) as a free-radical initiator and under LED (380–385 nm) irradiation and metal-free conditions, the reaction of alkynoates underwent smoothly to afford the corresponding coumarins in high yields at room temperature with broad substrate scope via free radical intramolecular cyclization and ester rearrangement.

Straightforward S-S Bond Formation via the Oxidation of S-Acetyl by Iodine in the Presence of N-Iodosuccinimide.

Straightforward S-S bond formation via the oxidation of S-acetyl group by iodine was reported here. The reaction was further applied in the synthesis of per-O-acetylated glycosyl disulfides. These studies demonstrated great improvement in reaction rate, yield, and general convenience in the presence of N-iodosuccinimide. Furthermore, selectively deacetylated glycosyl thiols were obtained in high yields when these per-O-acetylated glycosyl disulfides were reduced with tris(2-carboxyethyl)-phosphine (TCEP). Our method supplied an efficient way to obtain both per-O-acetylated glycosyl disulfides and per-O-acetylated glycosyl thiols in which the sulfur group was located at any position.

ChemInform Abstract: A Concise Approach for the Synthesis of 3‐Iodoindoles and 3‐Iodobenzo[b]furans via Ph3P‐Catalyzed Iodocyclization.

A variety of 3-iodoindole and 3-iodobenzo[b]furan derivatives were conveniently prepared from the corresponding 2-alkynylanilines and 2-alkynylphenols through Ph3P-catalyzed iodocyclization in the presence of N-iodosuccinimide (NIS). This protocol provides a rapid access to 3-iodoindoles and 3-iodobenzo[b]furans in good to excellent yields under mild conditions.

A concise approach for the synthesis of 3-iodoindoles and 3-iodobenzo[b]furans via Ph3P-catalyzed iodocyclization

A variety of 3-iodoindole and 3-iodobenzo[b]furan derivatives were conveniently prepared from the corresponding 2-alkynylanilines and 2-alkynylphenols through Ph3P-catalyzed iodocyclization in the presence of N-iodosuccinimide (NIS). This protocol provides a rapid access to 3-iodoindoles and 3-iodobenzo[b]furans in good to excellent yields under mild conditions.

An improved synthesis of 3,6-anhydro-d-glucal and a study of its unusual chemical reactivity

6-O-Tosyl-d-glucal 1 upon treatment with excess LiAlH4 unexpectedly gave 3,6-anhydro-d-glucal 2 as a major product in good yield. A crystal structure was obtained. Reaction of the anhydride 2 with N-iodosuccinimide (NIS) in excess methanol resulted in the formation of diastereomeric 2-deoxy-2-iodoglycosides. Addition of ceric (IV) ammonium nitrate and thiophenol to a solution of 2 in acetonitrile gave a mixture of 2-deoxy and 2,3-unsaturated thioglycosides. Reaction of 1,2:3,4-di-O-isopropylidine-α-d-galactopyranose with the anhydro sugar 2 in the presence of N-iodosuccinimide did not give the expected iodoglycoside mixture, but instead gave an unusual 1,4:3,6-dianhydride 7 as the major product.

A facile preparation of various N-heterocycles using amides and olefins

We herein report a one pot approach for the synthesis of various nitrogen containing heterocycles including: oxazolines, thiazolines, and dihydro dioxazines via the addition of amides to olefins in the presence of N-iodosuccinimide (NIS) and propionitrile at high temperatures. Thus, the reaction of aryl/heteroaryl amides, thioamides, N-hydroxybenzamide, and phenylurea with various olefins in the presence of NIS and propionitrile at 45°C afforded the N-heterocycles in good to moderate yields. Reaction of the electron deficient tri-O-acetyl-d-glucal and tri-O-acetyl-d-galactal with benzamide and thiophene-2-carboxamide afforded the N-glycooxazolines in good yields. The newly made heterocycles were tested against various enzymes. Only 3,6-diphenyl-dihydro-1,4,2-dioxazine (1c) was found to moderately inhibit hexokinase II (hHK2).

N‐Iodosuccinimide: A Highly Effective Regioselective Reagent for Iodoesterification of Alkenes

AbstractA rapid, convenient, and efficient method has been achieved for regioselective iodoesterification of alkenes with aliphatic and aromatic acids, and protected amino acids in the presence of N‐iodosuccinimide (NIS) in nearly quantitative yields. Optically enriched iodohydrins have been achieved by LiAlH4 (LAH) reduction of diastereoisomeric iodo esters.

NIS-Mediated Electrophilic Cyclization of 3-Silyloxy-1,n-enynes

The electrophilic cyclization of 3-silyloxy-1,5-enynes and 3-silyloxy-1,6-enynes was investigated. In the presence of N-iodosuccinimide (NIS), the title compounds are transformed under metal-free conditions into five-membered carbocycles with all-carbon stereogenic centers following a sequence of iodonium activation of the triple bond, carbocyclization, and pinacol-type 1,2-shift.

3-Alkenylation or 3-Alkylation of Indole with Propargylic Alcohols: Construction of 3,4-Dihydrocyclopenta[b]indole and 1,4-Dihydrocyclopenta[b]indole in the Presence of Different Catalysts

3-Alkenylation or 3-alkylation of indole with propargylic alcohols could be efficiently controlled by the catalyst. In the presence of triflic acid, 3-alkenylation of indole occurred and a 3,4-dihydrocyclopenta[b]indole skeleton was effectively constructed in moderate to excellent yields via a cascade process. In the presence of Cu(OTf)(2), 3-alkylation of indole resulted in the formation of 3-propargylic indole, which could be further converted into 2-iodo-1,4-dihydrocyclopenta[b]indoles in the presence of N-iodosuccinimide and boron trifluoride etherate. Possible mechanisms related to the 3-alkenylation or 3-alkylation of indole and their extension to the formation of 3,4-dihydrocyclopenta[b]indoles or 1,4-dihydrocyclopenta[b]indoles are postulated and discussed.

Synthesis of 4′-Ethynyl-2′-deoxy-4′-thioribonucleosides and Discovery of a Highly Potent and Less Toxic NRTI

The synthesis of 4'-ethynyl-2'-deoxy-4'-thioribonucleosides was carried out utilizing an electrophilic glycosidation in which 4-ethynyl-4-thiofuranoid glycal 16 served as a glycosyl donor. Electrophilic glycosidation between 16 and the silylated nucleobases (N4-acetylcytosine, N6-benzoyladenine and N2-acetyl-O6-diphenylcarbamoylguanine) was carried out in the presence of N-iodosuccinimide (NIS) leading to the exclusive formation of the desired β-anomers 29, 33 and 36. Anti-HIV studies demonstrated that these 4'-thio nucleosides were less cytotoxic to T-lymphocyte (i.e. MT-4 cells) than the corresponding 4'-ethynyl derivatives of 2'-deoxycytidine (44), 2'-deoxyadenosine (45) and 2'-deoxyguanosine (46). Comparison of the selectivity indices (SI) was made between 4'-thionucleosides (32, 41 and 43) and the corresponding 4'-oxygen analogues 44-46 by using the reported CC50 and EC50 values. In the case of cytosine and adenine nucleosides, comparable SI values were obtained: 32 (545) and 45 (458); 41 (>230) and 45 (1,630). In contrast, 4'-ethynyl-2'-deoxy-4'-thioguanosine 43 was found to possess a SI value of >18,200, which is twenty times better than that of 46 (933).

A Novel and Highly Stereoselective Synthesis of 2-Substituted Perhydrofuro[2,3-b]pyran Derivatives

An effective and facile method for the synthesis of 2-substituted perhydrofuro[2,3-b]pyran derivatives is described. The cyclization of 2-C-aldehydo-2-deoxy-D-thioglucoside in the presence of N-iodosuccinimide (NIS) is highly stereoselective. 2-Substituted cyclization products were obtained in good to excellent yields.

One-Pot Approach to the Conversion of Alcohols into α-Iodo-α,β-unsaturated Esters

(Carboethoxymethylene)triphenylphosphorane 1 can undergo the tandem reaction of iodination–oxidation–Wittig reaction with alcohol in the presence of N-iodosuccinimide (NIS) and manganese dioxide. The reaction constitutes a stereoselective one-pot procedure for the preparation of Z-configured α-iodo-α,β-unsaturated esters in good to excellent yield.