- Solvent-free conversion of alcohols into iodides with NaI supported on KSF clay
-
A variety of allylic, benzylic, primary, and secondary saturated alcohols have been converted into the corresponding iodides using NaI supported on KSF clay. Selective conversion of allylic and benzylic alcohols in the presence of primary and secondary saturated alcohols has also been demonstrated. Copyright Taylor & Francis, Inc.
- Tajbakhsh, Mahmood,Hosseinzadeh, Rahman,Lasemi, Zahra,Rostami, Ali
-
-
Read Online
- Iminophosphorane-mediated regioselective umpolung alkylation reaction of α-iminoesters
-
Umpolung reactions of imines, especially the asymmetric reactions, have been extensively studied as they provide access to important chiral amines in an efficient manner. The reactions studied range from simple Michael reactions to several kinds of other reactions such as the aza-benzoin reaction, aza-Stetter reaction, addition with MBH carbonate, and Ir-catalysed allylation. Herein, we report the first umpolung alkylation reaction of α-iminoesters with alkyl halides mediated by iminophosphorane as an organic superbase. The desired products were obtained in up to 82% yield with almost perfect regioselectivities. The key to the regioselectivity of this reaction was the use of 4-trifluoromethyl benzyl imines as a substrate. The products were successfully derivatised into the more functionalised molecules in good yields.
- Kukita, Mayu,Mino, Takashi,Omori, Kazuki,Sakamoto, Masami,Yoshida, Yasushi
-
-
Read Online
- Selective iodination of alcohols with NaI/Amberlyst 15 in acetonitrile
-
A simple and effective procedure for conversion of primary, secondary, allylic and benzylic alcohols into the corresponding iodides is described using NaI/Amberlyst 15 in acetonitrile at room temperature. Selective conversion of benzylic alcohols in the presence of saturated alcohols into the corresponding benzylic iodides is achieved under these conditions.
- Tajbakhsh, Mahmood,Hosseinzadeh, Rahman,Lasemi, Zahra
-
-
Read Online
- Enhancing the leaving group ability of alkyl fluorides: I/F exchange reactions mediated by LiI
-
The carbon–fluorine (C–F) bond is one of the strongest bonds in organic chemistry and generally inert toward nucleophilic substitution reactions. To overcome the relative inertness of the C–F bond, this work focused on the ability of simple lithium salts
- Bagnall, Brody,Davis, Todd A.,Zerban, Jensen J.
-
supporting information
(2022/01/28)
-
- Preparation method of benzyl iodide and derivatives thereof
-
The invention discloses a preparation method of benzyl iodide and derivatives thereof. The preparation method comprises the following steps: under the reduction action of sodium borohydride, a benzylalcohol compound shown as a formula I reacts with elemental iodine to obtain benzyl iodide shown as a formula II and derivatives thereof; in the formula I and the formula II, R represents one or moresubstituents on a benzene ring and is selected from at least one of aryl, substituted or unsubstituted alkyl, halogen and nitro. The preparation method of benzyl iodide and derivatives thereof is scientific and reasonable, sodium borohydride which is mild in reactivity, low in price and easily available is used as a reducing agent, and elemental iodine is convenient and easily available; in addition, the preparation method has the characteristics of simplicity and convenience in operation, high synthesis yield, easiness in product purification, environmental friendliness and the like.
- -
-
Paragraph 0095-0099
(2020/06/09)
-
- Rhodium-Catalyzed Generation of Anhydrous Hydrogen Iodide: An Effective Method for the Preparation of Iodoalkanes
-
The preparation of anhydrous hydrogen iodide directly from molecular hydrogen and iodine using a rhodium catalyst is reported for the first time. The anhydrous hydrogen iodide generated was proven to be highly active in the transformations of alkenes, phenyl aldehydes, alcohols, and cyclic ethers to the corresponding iodoalkanes. Therefore, the present methodology not only has provided convenient access to anhydrous hydrogen iodide but also offers a practical preparation method for various iodoalkanes in excellent atom economy.
- Zeng, Chaoyuan,Shen, Guoli,Yang, Fan,Chen, Jingchao,Zhang, Xuexin,Gu, Cuiping,Zhou, Yongyun,Fan, Baomin
-
supporting information
p. 6859 - 6862
(2018/10/25)
-
- Catalytic Halogen Bond Activation in the Benzylic C-H Bond Iodination with Iodohydantoins
-
This letter presents the side-chain iodination of electron-deficient benzylic hydrocarbons at rt using N-hydroxyphthalimide (NHPI) as radical initiator and 1,3-diiodo-5,5-dimethylhydantoin and 3-iodo-1,5,5-trimethylhydantoin (3-ITMH) as iodine source. Addition of a carboxylic acid increased the reactivity due to complex formation with and activation of 3-ITMH by proton transfer and halogen bond formation. No SEAr reactions were observed under the employed reaction conditions. Our method enables convenient product isolation and gives 50-72% yields of isolated products.
- Combe, Sascha H.,Hosseini, Abolfazl,Song, Lijuan,Hausmann, Heike,Schreiner, Peter R.
-
supporting information
p. 6156 - 6159
(2017/11/24)
-
- A mild and highly chemoselective iodination of alcohol using polymer supported DMAP
-
The synthesis of organic compounds using polymer supported catalysts and reagents, where the required product is always in solution, has been of great interest in recent years, both in industries and academia especially in pharmaceutical research. Here, a simple and efficient method for conversion of alcohols into their iodides in high yield using polymer supported 4-(Dimethylamino)pyridine (DMAP) is described. Polymer supported DMAP is used in catalytic amount and is recovered and reused several times. Additionally, this method is highly chemoselective. [Figure not available: see fulltext.]
- Das, Diparjun,H Anal, Jasha Momo,Rokhum, Lalthazuala
-
p. 1695 - 1701
(2017/03/08)
-
- An efficient and selective method for the iodination and bromination of alcohols under mild conditions
-
A straightforward and effective procedure for the conversion of a variety of alcohols into the corresponding alkyl iodides and bromides is described using KX/P2O5 (X = I, Br). The reactions were easily carried out in acetonitrile under mild conditions. Using this method, the selective conversion of benzylic alcohols in the presence of aliphatic alcohols was achieved.
- Khazdooz, Leila,Zarei, Amin,Aghaei, Hamidreza,Azizi, Ghobad,Gheisari, Mohammad Mehdi
-
p. 168 - 171
(2015/12/30)
-
- One-Pot Transformation of Aliphatic Carboxylic Acids into N-Alkylsuccin-imides with NIS and NCS/NaI
-
Primary aliphatic carboxylic acids were treated with N-iodosuccinimide (NIS) in 1,2-dichloroethane to form the corresponding alkyl iodides under warming conditions. Based on these results, those aliphatic carboxylic acids were treated with NIS, followed by the reaction with K2CO3to give the corresponding N-alkylsuccinimides in good yields in one pot. Moreover, those aliphatic carboxylic acids were treated with N-chlorosuccinimide (NCS) and NaI, followed by the reaction with K2CO3to provide the corresponding N-alkylsuccinimides in good to moderate yields in one pot. By using the present method, successive treatment of primary aliphatic carboxylic acids (10 mmol) with NIS, K2CO3, and then hydrazine provided the corresponding decarboxylated primary amines in good yield.
- Nakai, Yuhta,Moriyama, Katsuhiko,Togo, Hideo
-
p. 768 - 772
(2017/01/18)
-
- Uranyl Schiff base complexes as new heterogeneous catalysts for halogen exchange reactions between alkyl halides and elemental halogens
-
Mild and effective procedure for the halogen exchange reaction of alkyl halides with elemental iodine and bromine catalyzed with uranyl Schiff base complexes in various aprotic solvents was developed. Corresponding alkyl bromides and iodides were obtained with high yields within 20—70 min. The structures of the target products were confirmed by physical and spectroscopic data.
- Naeimi,Nazifi
-
p. 1814 - 1818
(2016/05/11)
-
- Design, synthesis and anticancer activities of novel otobain derivatives
-
A series of novel racemic otobain derivatives was designed and synthesised using 2-piperonyl-1,3-dithianes in the conjugate addition-alkylation to 5H-furan-2-one, followed by cationic cyclisation. All the synthesised compounds were consequently evaluated for their anticancer activity against several human cancers in vitro. The efficacy of the most active compound 27g was comparable with etoposide, with IC50 values ranging from 1.06 μM to 4.16 μM in different cancer cell lines. Notably, compound 27g strongly induced cell cycle arrest and increased the expression of mitosis-specific markers MPM-2 and phosphorylated histone H3, but it did not trigger cell apoptosis. Further a colony formation assay showed that compound 27g effectively inhibited the anchor growth of lung cancer cells in a dose-dependent manner. More importantly, compound 27g at 40 mg kg-1 significantly suppressed tumour volume (P 0.01) and tumour weight (P 0.05) in a human lung cancer cell xenograft mouse model without causing systematic toxicity in mice. Our findings indicated that compound 27g has significant potential for further drug development.
- Li, Zhongzhou,Su, Hui,Yu, Weiwei,Li, Xinjun,Cheng, Hao,Liu, Mingyao,Pang, Xiufeng,Zou, Xinzhuo
-
p. 277 - 287
(2015/12/30)
-
- Application of "click" chemistry in solid phase synthesis of alkyl halides
-
A convenient and highly selective microwave assisted procedure for the conversion of allylic, benzylic and aliphatic alcohols to their corresponding halides using polymer-bound triphenylphosphine and iodine is presented. In case of symmetrical diols, mono-iodination product is obtained in very high yield. Additionally, highly regioselective behavior is observed in our procedure. Simplicity in operation, no column chromatography required for the purification of the products, recyclability of the reagents used, short reaction times and good to excellent yields are the advantages of our protocol. Most functional groups remain unaffected under our reaction condition.
- Das, Diparjun,Chanda, Tridib,Rokhum, Lalthazuala
-
p. 775 - 783
(2016/01/20)
-
- Novel aminotetrazole derivatives as selective STAT3 non-peptide inhibitors
-
The development of inhibitors blocking STAT3 transcriptional activity is a promising therapeutic approach against cancer and inflammatory diseases. In this context, the selectivity of inhibitors against the STAT1 transcription factor is crucial as STAT3 and STAT1 play opposite roles in the apoptosis of tumor cells and polarization of the immune response. A structure-based virtual screening followed by a luciferase-containing promoter assay on STAT3 and STAT1 signaling were used to identify a selective STAT3 inhibitor. An important role of the aminotetrazole group in modulating STAT3 and STAT1 inhibitory activities has been established. Optimization of the hit compound leads to 23. This compound inhibits growth and survival of cells with STAT3 signaling pathway while displaying a minimal effect on STAT1 signaling. Moreover, it prevents lymphocyte T polarization into Th17 and Treg without affecting their differentiation into Th1 lymphocyte.
- Pallandre, Jean-René,Borg, Christophe,Rognan, Didier,Boibessot, Thibault,Luzet, Vincent,Yesylevskyy, Semen,Ramseyer, Christophe,Pudlo, Marc
-
supporting information
p. 163 - 174
(2015/09/21)
-
- Synthesis of a novel series of 2,3,4-trisubstituted oxazolidines designed by isosteric replacement or rigidification of the structure and cytotoxic evaluation
-
We have previously reported on a study of the structure-activity relationship in a series of 2,3,4-substituted oxazolidines recently discovered by our group varying the substituent at the ring or stereochemistry of the oxazolidine ring. We discovered the cytotoxic and pro-apoptotic potential of compounds 1 and 2 with good selectivity against cancer cell lines. In the present study we describe the synthesis and cytotoxic evaluation against cancer cell lines (HL60, JURKAT, MDA-MB-231 and LNCaP) of a series of oxazolidines designed by isosteric replacement or rigidification of the oxymethylene spacer of compounds 1 and 2. Alkenes 3 and 4 retained the activity against MDA-MB-231 cells and they were more active on HL60, JURKAT and LNCaP cells. Considering LNCaP cells, E-isomer 4 was at least 7 times and about 3 times more potent than lead 1 and Z-isomer 3, respectively. Compound 4 exerted significant activity against LNCaP with IC50 in the low micromolar range (11 μM) without affecting VERO cells and PBMC proliferation (IC50 > 100 μM) indicating its low toxicity to normal cells.
- Andrade, Saulo F.,Teixeira, Claudia S.,Ramos, Jonas P.,Lopes, Marcela S.,Pdua, Rodrigo M.,Oliveira, Mnica C.,Souza-Fagundes, Elaine M.,Alves, Ricardo J.
-
supporting information
p. 1693 - 1699
(2014/12/11)
-
- Ionic liquid-induced conversion of methoxymethyl-protected alcohols into nitriles and iodides using [Hmim][NO3]
-
This Letter reports a one-pot efficient conversion of methoxymethyl-ethers into their corresponding nitriles and iodides using the ionic liquid, 1-methyl-3H-imidazolium nitrate ([Hmim][NO3]) under microwave irradiation. A variety of products were prepared in high yields using this method.
- Noei, Jalil,Mirjafari, Arsalan
-
supporting information
p. 4424 - 4426
(2014/08/05)
-
- Efficient and selective iodination of benzylic alcohols using NaI/bronsted ionic liquid system at room temperature
-
A simple, chemoselective, and effective procedure for the conversion of benzylic and allylic alcohols into corresponding iodides using NaI in the presence of a catalytic amount of 3-methylimidazolium hydrogensulfate ([Hmim]+[image omitted]) at room temperature is reported.
- Hajipour, Abdol R.,Rafiee, Fatemeh,Ruoho, Arnold
-
experimental part
p. 603 - 611
(2011/04/15)
-
- Treatment of alcohols with tosyl chloride does not always lead to the formation of tosylates
-
Treatment of substituted benzyl alcohols with tosyl chloride resulted in the formation of the corresponding chlorides, not the usual tosylates. A series of experiments demonstrated that it was possible to predict whether chlorination or tosylation would occur for substituted benzyl alcohols and pyridine methanols. Treatment of electron withdrawing group-substituted benzyl alcohols with tosyl chloride gave the corresponding chlorides in moderate yields under mild conditions, which provided a simple way to directly prepare chlorides from alcohols.
- Ding, Rui,He, Yong,Wang, Xiao,Xu, Jingli,Chen, Yurong,Feng, Man,Qi, Chuanmin
-
body text
p. 5665 - 5673
(2011/09/20)
-
- Efficient organic transformations mediated by ZrOCl28H 2O in Water
-
Operationally simple and environmentally benign methods for some organic transformations comprising reductive coupling of sulfonyl chlorides, chemoselective deoxygenation of sulfoxides, and halogenation of alcohols mediated by ZrOCl28H2O/MX in water have been developed.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Heidari, Mahdieh
-
experimental part
p. 1470 - 1482
(2011/10/05)
-
- Iodination of alcohols over Keggin-type heteropoly compounds: A simple, selective and expedient method for the synthesis of alkyl iodides
-
Different catalysts derived from Keggin-type heteropoly compounds were prepared and their catalytic activities have been compared in the iodination of benzyl alcohol with KI under mild reaction conditions. A high catalytic activity was found over tungstophosphoric acid supported on silica and titania. The effect of catalyst loading, iodine source and the nature of substituents on the aromatic ring of benzyl alcohol were investigated. Finally, several competitive reactions were studied between structurally diverse alcohols. This protocol provides a mild and expedient way for the conversion of various alcohols to their corresponding alkyl iodides with high selectivity.
- Rafiee, Ezzat,Mahdavia, Houri,Joshaghani, Mohammad
-
experimental part
p. 135 - 140
(2011/06/09)
-
- Microwave-promoted, one-pot conversion of alkoxymethylated protected alcohols into their corresponding nitriles, bromides, and iodides using [bmim][InCl4] as a green catalyst
-
The Lewis acid room temperature ionic liquid, [bmim][InCl4], was found to be an efficient and green catalyst for the highly chemoselective and one-pot conversion of MOM- or EOM-ethers into their corresponding nitriles, bromides, and iodides under microwave irradiation. The procedures are simple, rapid, and high yielding. The catalyst exhibited a remarkable reactivity and is reusable.
- Mirjafari, Arsalan,Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Khosropour, Ahmad Reza
-
supporting information; experimental part
p. 3274 - 3276
(2010/07/18)
-
- Iodination of alcohols under microwave irradiation using KI in the presence of a catalytic amount of ionic liquid triethylamoniom hydrogensulfate([Et 3NH]+HSO4-)
-
The iodination of alcohols with KI in the presence of a catalytic amount of triethylamoniom hydrogensulfate ([Et3NH]+HSO 4-) as a novel and inexpensive ionic liquid under microwave irradiation has been investigated. Copyright Taylor & Francis Group, LLC.
- Hajipour, Abdol R.,Azizi, Ghobad,Ruoho, Arnold E.
-
experimental part
p. 242 - 250
(2009/04/07)
-
- Establishment of heterolytic and homolytic Y-NO2 bond dissociation energy scales of nitro-containing compounds in acetonitrile: Chemical origin of NO2 release and capture
-
(Chemical Equation Presented) The first heterolytic and homolytic N(O)-NO2 bond dissociation energy scales of three types Y-nitro (Y = N, O) compounds and corresponding radical anions in acetonitrile were established by using titration calorimetry combined with relevant electrochemical data through proper thermodynamic cycles.
- Li, Xin,Zhu, Xiao-Qing,Zhang, Fan,Wang, Xiao-Xiao,Cheng, Jin-Pei
-
p. 2428 - 2431
(2008/09/20)
-
- An expedient stereoselective synthesis of (Z)- and (E)-allyl iodides from Baylis-Hillman adducts along with selective iodination of benzylic alcohols using the polymethylhydrosiloxane-iodine system
-
A stereoselective method has been developed for the synthesis of (Z)- and (E)-allyl iodides from Baylis-Hillman adducts using polymethylhydrosiloxane (PMHS) and iodine in chloroform at room temperature. In addition, the reagent system has been utilized for the iodination of benzylic alcohols selectively.
- Das, Biswanath,Holla, Harish,Srinivas, Yallamalla,Chowdhury, Nikhil,Bandgar
-
p. 3201 - 3204
(2007/10/03)
-
- Synthesis of N-protected indolaldehydes using modified Hass procedure
-
A detailed study on oxidation of N-protected bromomethylindoles into the respective aldehydes was carried out. Using a modified Hass procedure, synthesis of aryl-/hetero-aryl aldehydes in particular indolaldehydes is achieved in reasonable yields.
- Balamurugan, Ramalingam,Mohanakrishnan, Arasambattu K.
-
p. 11078 - 11085
(2008/02/12)
-
- Allyl and benzyl iodides by the anomalous action of iodotrimethylsilane
-
Iodotrimethylsilane (TMSI), routinely used for the dealkylation of ethers and esters, has been found to efficiently convert allyl and benzyl phosphotriesters into the corresponding iodides under mild, Bronsted-neutral conditions. In contrast, alkyl and aryl phosphotriesters were dealkylated to the corresponding phosphates under identical conditions.
- Zhu, Qing,Tremblay, Matthew S.
-
p. 6170 - 6172
(2007/10/03)
-
- Convenient and efficient method for the iodination of benzylic and aliphatic alcohols by using Al(HSO4)3/KI in nonaqueous solution
-
A simple and efficient method for the iodination of benzylic and aliphatic alcohols by using Al(HSO4)3/KI in n-hexane as solvent is reported. Mild reaction conditions and good to excellent yields of the products are the noteworthy advantages of the method. Copyright Taylor & Francis LLC.
- Tajik, Hassan,Shirini, Farhad,Zolfigol, Mohammad Ali,Samimi, Faeze
-
-
- Facile conversion of alcohols into their bromides and iodides by N-bromo and N-iodosaccharins/triphenylphosphine under neutral conditions
-
N-Bromo and N-iodosaccharins in the presence of triphenylphosphine convert alcohols into the corresponding bromides and iodides in good to excellent yields at room temperature under neutral conditions.
- Firouzabadi, Habib,Iranpoor, Nasser,Ebrahimzadeh, Farzaneh
-
p. 1771 - 1775
(2007/10/03)
-
- Iodination of alcohols using triphenylphosphine/iodine under solvent-free conditions using microwave irradiation
-
A straightforward and effective procedure for the conversion of benzylic, allylic and aliphatic alcohols to the corresponding iodides using Ph3P/I2 under solvent-free conditions using microwave irradiation is reported.
- Hajipour, Abdol Reza,Falahati, Ali Reza,Ruoho, Arnold E.
-
p. 4191 - 4196
(2007/10/03)
-
- Efficient method for iodination of alcohols using KI/silica sulfuric acid (SSA)
-
A straightforward and effective procedure for the conversion of benzylic and allylic alcohols to the corresponding iodides using KI/SSA in acetonitrile at room temperature. Copyright Taylor & Francis Group, LLC.
- Hajipour, Abdol R.,Zarei, Amin,Ruoho, Aronold E.
-
p. 1039 - 1050
(2007/10/03)
-
- 4-Aminophenyldiphenylphosphinite (APDPP), a new heterogeneous and acid scavenger phosphinite - Conversion of alcohols, trimethylsilyl, and tetrahydropyranyl ethers to alkyl halides with halogens or N-halosuccinimides
-
A new heterogeneous phosphinite, 4-aminophenyldiphenylphosphinite (APDPP), is prepared and used for the efficient conversion of alcohols, trimethylsilyl ethers, and tetrahydropyranyl ethers to their corresponding bromides, iodides, and chlorides in the presence of molecular halogens or N-halosuccinimides. The amino group in this phosphinite acts as an acid scavenger and removes the produced acid. A simple filtration easily removes the phosphinate by-product.
- Iranpoor, Nasser,Firouzabadi, Habib,Gholinejad, Mohammad
-
p. 1006 - 1012
(2007/10/03)
-
- Silicaphosphine (Silphos): A filterable reagent for the conversion of alcohols and thiols to alkyl bromides and iodides
-
Silicaphosphine (Silphos), [P(Cl)3-n(SiO2) n], as a new heterogeneous reagent is introduced. This reagent converts alcohols and thiols to their corresponding bromides and iodides in the presence of X2 (X=Br, I) in refluxing CH3CN in high to quantitative yields. Use of Silphos provides a highly practical method for the easy separation of the Silphos oxide byproduct by a simple filtration.
- Iranpoor, Nasser,Firouzabadi, Habib,Jamalian, Arezu,Kazemi, Foad
-
p. 5699 - 5704
(2007/10/03)
-
- Efficient and selective halogenation of allylic and benzylic alcohols under mild conditions
-
A simple, mild, and high yielding procedure for the halogenation of allylic and benzylic alcohols using a combination of SOCl2, benzotriazole, and potassium halides in DMF is described. The effectiveness of the protocol is manifested in its selectivity towards allylic and benzylic alcohols whereas other simple alcohols such as primary, secondary, and tertiary are found to be unreactive. Springer-Verlag 2004.
- Bandgar, Babasaheb P.,Bettigeri, Sampada V.
-
p. 1251 - 1255
(2007/10/03)
-
- Facile preparation of benzylic iodides under solvent-free conditions using microwave irradiation
-
Benzylic alcohols are rapidly converted to the corresponding benzylic iodides using combination of p-toluenesulfonic acid (PTSA) and potassium iodide under solvent-free microwave irradiation conditions.
- Lee, Jong Chan,Park, Jin Young,Yoo, Eun Sang
-
p. 2095 - 2099
(2007/10/03)
-
- A simple, efficient, and highly selective method for the iodination of alcohols using ZrCl4/NaI
-
Iodination of primary, secondary, allylic, and benzylic alcohols giving their corresponding iodides was achieved with ZrCl4/NaI in anhydrous CH3CN with excellent yields and selectivities.
- Firouzabadi, Habib,Iranpoor, Nasser,Jafarpour, Maasoumeh
-
p. 7451 - 7454
(2007/10/03)
-
- Selective functionalisation of hydrocarbons by nitric acid and aerobic oxidation catalysed by N-hydroxyphthalimide and iodine under mild conditions
-
Alkylbenzenes are selectively functionalised to the corresponding acetates by nitric aerobic oxidation catalysed by N-hydroxyphthalimide and iodine. With cyclohexane the oxidation leads to a mixture of cyclohexyl acetate and trans-2-iodocyclohexyl acetate. The mechanism is discussed.
- Minisci, Francesco,Recupero, Francesco,Gambarotti, Cristian,Punta, Carlo,Paganelli, Roberto
-
p. 6919 - 6922
(2007/10/03)
-
- An alternative method for the highly selective iodination of alcohols using a CsI/BF3·Et2O system
-
A variety of allylic and benzylic alcohols have been converted into the corresponding iodides using cesium iodide (CsI) in the presence of boron trifluoride etherate (BF3·Et2O) in acetonitrile under mild conditions.
- Hayat, Safdar,Atta-Ur-Rahman,Khan, Khalid Mohammed,Choudhary, M. Iqbal,Maharvi, Ghulam Murtaza,Zia-Ullah,Bayer, Ernst
-
p. 2531 - 2540
(2007/10/03)
-
- Selective iodination of benzylic alcohols with KI/H2SO4 supported on natural kaolinitic clay under microwave irradiation
-
Benzylic alcohols are selectively converted into their corresponding iodides using KI/H2SO4 supported on natural kaolinitic clay and microwaves.
- Bandgar, Babasaheb P.,Sadavarte, Vibhav S.,Bettigeri, Sampada V.
-
p. 345 - 348
(2007/10/03)
-
- Thermolysis of tert-butyl phenylperacetates: Delicate control of the rates through contributions from translational and rotational entropy
-
The first-order rate constants (ky) at several temperatures in CDCl3 were measured for thermal decompositions of YC6H4CH2CO3C(CH3) 3 with Y being p-OCH3, p-OPh, p-CH3, p-Ph, p-H, p-Cl, m-Cl, and p-NO2. The relative rates (ky/kH) exhibit excellent ρ+/σ+ Hammett correlations with ρ+ a polar TS. Activation parameters (ΔH?Y and ΔS?Y) and their differential terms (ΔΔH?Y-H and ΔΔS?Y-H) were obtained from the Eyring plot. Differential activation terms (ΔΔH?Y-H and ΔΔS?Y-H) disclose an isokinetic relation with p-CH3, p-Ph, p-H, p-Cl, and m-Cl (isokinetic temp, 230 K). However, p-OCH3, and p-OPh show negative deviations, and a positive deviation occurs with p-NO2. Plot of ΔΔH?Y-H vs σ+ exhibits a good linear relation (r = 0.95) with a slope (α1 = -3.34). A better linear correlation (r = 0.97) and steeper slope (α2 = -5.22) were observed for TΔΔS?Y-H vs σ+. Negatively larger slope (α2 = -5.22) may point to entropy control of rates. Differential activation parameters (ΔΔHS?Y-H and ΔΔS?Y-H) reflect variations of activation process. Differential activation entropies (ΔΔS?Y-H) are discussed in terms of contributions of translational and rotational entropies. Similar deviation behaviors of p-OCH3, p-OPh, and p-NO2 were again observed for the both plots. p-NO2 can strongly destabilize the cationic site of the polar TS but serves an eminent spin delocalizer for the homolytic TS.
- Kim,Baek,Tuchkin,Go
-
p. 4006 - 4011
(2007/10/03)
-
- An expedient and highly selective iodination of alcohols using a KI/BF3·Et2O system
-
Alkyl iodides are prepared in high yields by treatment of allylic and benzylic alcohols with an equimolar amount of KI in the presence of BF3·Et2O in dioxane under mild conditions.
- Bandgar,Sadavarte,Uppalla
-
p. 951 - 953
(2007/10/03)
-
- Oxidation of Aromatic Compounds. I. Oxidation of Methyl Derivatives of Nitrobenzene and Aniline in the System HSO3F-PbO2
-
Low-temperature oxidation of methyl derivatives of nitrobenzene and aniline in the system HSO3F-PbO2 proceeds with intermediate formation of radical cations and results in replacement of hydrogen in one or two methyl groups or yields compounds of the diphenylmethane and biphenyl series.
- Rudenko, A. P.,Korovina, N. S.,Aver'yanov, S. F.
-
p. 1077 - 1083
(2007/10/03)
-
- Benzylation via Tandem Grignard Reaction - Iodotrimethylsilane (TMSI) Mediated Reduction
-
A method has been developed which allows for the large scale preparation of biarylmethanes.This method involves the initial formation of biarylmethanols via reaction of aryl Grignards with carbonyl compounds followed by a subsequent reduction with iodotrimethylsilane (TMSI).A number of improvements over existing literature procedures are reported as well as previously unobserved dimerizations.Studies reveal that as few as 3 equiv of TMSI will give complete reduction in most cases where either of the substituents are not heteroaromatic.Mono-substituted alkanols react with TMSI to afford the corresponding iodides.A mechanistic study of the TMSI reduction is also reported.
- Stoner, Eric J.,Cothron, Darlene A.,Balmer, Mary K.,Roden, Brian A.
-
p. 11043 - 11062
(2007/10/02)
-
- Antitumor agents. 120. New 4-substituted benzylamine and benzyl ether derivatives of 4'-O-demethylepipodophyollotoxin as potent inhibitors of human DNA topoisomerase II
-
A number of new 4'-O-demethylepipodophyllotoxin derivatives possessing various 4β-N- or 4β-O-benzyl groups have been synthesized and evaluated for their inhibitory activity against the human DNA topoisomerase II as well as for their activity in causing cellular protein-linked DNA breakage. The 4β-N-benzyl derivatives 9-22 are, in general, as active or more active than etoposide (1). The most active compounds are 14, 16, and 17, which are more than 2-fold more potent than 1. The results indicated that a basic unsubstituted 4β-benzylamino moiety is structurally required for the enhanced activity. Replacement of the benzyl nitrogen with oxygen gave compounds (23 and 24) which are inactive. The ability of these compounds to inhibit human DNA topoisomerase II and to cause protein-linked DNA breakage appears to have no direct correlation with cytotoxicity in KB cells.
- Zhou,Wang,Chang,Chen,Cheng,Lee
-
p. 3346 - 3350
(2007/10/02)
-
- Changes of Selectivity in the Reactions of Substituted 4-Nitrobenzyl Sulfonates with Nucleophilic Reagents
-
The selectivities for anionic nucleophilic reagents are larger for reaction with 4-nitrobenzyl mesylate than with the corresponding triflate.Selectivities were determined over a range of rate constants of ca. 1E4 for nucleophiles and ca. 1E5 for 4-nitrobenzyl sulfonates in 20:80 CH3CN/HOH (v:v) at 25 deg C, ionic strength 0.5 M (NaClO4).The slope of a correlation of log (kN/kHOH) for the two compounds is 1.12.Larger increases in selectivity of up to 11-fold were observed with more basic nucleophiles.The size of the additional increase is roughly proportional tothe basicity of the nucleophile, and it is suggested that reaction of the partially desolvated species may contribute to these differences.The results are described by a positive interaction coefficient pxy = s'/ log kHOH = s1g/ log knuc = 0.026.No significant change in selectivity of p-nitrobenzyl tosylate, nosylate, and triflate toward substituted anilines was observed over a 5-6-fold range of amine reactivity.The values of βnuc = 0.31 and 0.26 for the reactions of substituted anilines and aliphatic amines, respectively, with 4-nitrobenzyl tosylate do not differ significantly (70:30 EtOH/HOH (v:v), 25 deg C).The tosylate anion is a stronger nucleophile than water toward 4-nitrobenzyl triflate.It is concluded that SN2 substitution reactions do follow the Hammond postulate, or "Bema Hapothle", but that the small magnitude of the changes in selectivity requires the examination of a large range of reactivity for both the nucleophile and the substrate.
- Dietze, Paul,Jencks, William P.
-
p. 5880 - 5886
(2007/10/02)
-
- NEW PREPARATIONS OF p-NITROPHENYLCYCLOPROPANE
-
The preparation of p-nitrocyclopropylbenzene by reaction of dimethyloxosulfonium methylide with p-nitrostyrene or p-nitrobenzyl iodide (bromide) in 67 and 37 percent yield respectively is reported.
- Broos, R.,Anteunis, M. J. O.
-
p. 135 - 138
(2007/10/02)
-
- HOMOLYTIC DISPLACEMENT AT CARBON. X. TOLUENESULPHONYL IODIDE AS A SOURCE OF TOLUENESULPHONYL RADICALS FOR THE FORMATION OF ALLYL-, BENZYL-, CYCLOPROPYLCARBINYL-, SPIROCYCLOPROPYLCYCLOALKYL-, BICYCLOALKYL-, AND BICYCLOALKYL-4-TOLYLSULPHONES FROM ORGANOCOBALOXIMES
-
4-Toluenesulphonyl iodide reacts thermally at alkylsulphone.Spiro- and bicyclo-alkyl compounds are also formed with other free radical precursors.The reactions are believed to take place through a chain mechanism in which cobaloxime(II), present adventitiously or formed by partial homolysis of the substrate, abstracts iodine from the toluenesulphonyl iodide to give the toluenesulphonyl radical, which attacks the organic ligand of the cobaloxime, preferably at the terminal olefinic carbon, thereby displacing cobaloxime(II) and giving the observed organic product.
- Ashcroft, Martyn R.,Bougeard, Peter,Bury, Adrian,Cooksey, Christopher J.,Johnson, Michael D.
-
p. 403 - 416
(2007/10/02)
-