- Promotion of Appel-type reactions by N-heterocyclic carbenes
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N-Heterocyclic carbenes (NHCs) have been extensively used as a versatile class of catalysts and ligands in organocatalytic and organometallic chemistry. However, there are only a small number of synthetic applications where they act as reagents. Here we demonstrate that NHCs can be used as stoichiometric redox reagents for Appel-type halogenation reactions of alcohols. This new reactivity reveals a fresh and interesting aspect and enriches the chemistry of NHCs in an underexplored area. The potential of performing this chemical transformation at the catalytic level using an NHC-oxide derivative is also investigated.
- Hussein, Mohanad A.,Nguyen, Thanh Vinh
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supporting information
p. 7962 - 7965
(2019/07/12)
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- Efficient Difluoromethylation of Alcohols Using TMSCF2Br as a Unique and Practical Difluorocarbene Reagent under Mild Conditions
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A general method for the efficient difluoromethylation of alcohols using commercially available TMSCF2Br (TMS=trimethylsilyl) as a unique and practical difluorocarbene source is developed. This method allows primary, secondary, and even tertiary alkyl difluoromethyl ethers to be synthesized under weakly basic or acidic conditions. The reaction mainly proceeds through the direct interaction between a neutral alcohol and difluorocarbene, which is different from the difluoromethylation of phenols. Moreover, alcohols containing other moieties that are also reactive toward difluorocarbene can be transformed divergently by using TMSCF2Br. This research not only solves the synthetic problem of difluorocarbene-mediated difluoromethylation of alcohols, it also provides new insights into the different reaction mechanisms of alcohol difluoromethylation and phenol difluoromethylation with difluorocarbene species.
- Xie, Qiqiang,Ni, Chuanfa,Zhang, Rongyi,Li, Lingchun,Rong, Jian,Hu, Jinbo
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supporting information
p. 3206 - 3210
(2017/03/17)
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- FUNCTIONALISED AND SUBSTITUTED INDOLES AS ANTI-CANCER AGENTS
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The present invention relates to anti-tropomyosin compounds, processes for their preparation, and methods for treating or preventing a disease or disorder, such as a proliferative disease (preferably cancer), using compounds of the invention.
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Page/Page column 58; 59
(2016/02/05)
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- Practical methods for the synthesis of trifluoromethylated alkynes: Oxidative trifluoromethylation of copper acetylides and alkynes
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Two practical and complementary methods are reported for the synthesis of trifluoromethylated alkynes. The first one, a mix-and-stir process, is based on the oxidative trifluoromethylation of readily available and bench-stable copper acetylides while the second one, which displays a broad substrate scope and has several advantages over existing procedures, is based on the oxidative copper-catalyzed direct trifluoromethylation of terminal alkynes. Both reactions provide user-friendly processes for the synthesis of trifluoromethylated acetylenes which can be easily obtained from readily available starting materials.
- Tresse, Cedric,Guissart, Celine,Schweizer, Stephane,Bouhoute, Yassine,Chany, Anne-Caroline,Goddard, Mary-Lorene,Blanchard, Nicolas,Evano, Gwilherm
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supporting information
p. 2051 - 2060
(2014/07/07)
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- Indium(III)-catalyzed one-pot synthesis of alkyl cyanides from carboxylic Acids
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The one-pot preparation of alkyl cyanides from carboxylic acids via alkyl iodides or alkyl bromides, which were in situ generated either by indium(III)-catalyzed reductive iodination or bromination of carboxylic acids, is described. Georg Thieme Verlag Stuttgart New York.
- Moriya, Toshimitsu,Shoji, Kohei,Yoneda, Shinichiro,Ikeda, Reiko,Konakahara, Takeo,Sakai, Norio
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p. 3233 - 3238
(2013/12/04)
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- PYRROLOPYRIMIDINE DERIVATIVES USEFUL AS MODULATORS OF MULTIDRUG RESISTANCE
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A compound which is a pyrrolopyrimidine of formula (I) wherein: R1 is selected from R9 and halogen; R2 is NR6R7; R3 is selected from H, C1-C6 alkyl which is unsubstituted or substituted and -(CH2) nAr; R4 is selected from H, C1-C6 alkyl and -(CH2)? Ar; or R3 and R4 form, together with the N and C atoms to which they are attached, a fused five-, six-, seven- or eight-membered N-containing saturated ring which is unsubstituted or substituted; R5 is selected from CN, C02R9,C(O)NR10R11, -(CH2)nOH, -(CH2)nR10Rn, -C=CH, -C(S)NR10R11, -C(NH2)=NOR9, -C(R9)=NOR9, -C(NH2)NH, -C(O)R9 and an unsaturated 5- or 6-membered heterocyclic group which contains 1, 2 or 3 heteroatoms selected from N, O and S and which is unsubstituted or substituted; R6 and R7, which are the same or different, are selected from C1-C6 alkyl which is unsubstituted or substituted, -(CH2)nX and -(CH2)nAr; or R6 and R7 form, together with the nitrogen atom to which they are attached, a saturated five-, six-, seven- or eight-membered heterocyclic group which contains one nitrogen atom and 0 or from 1 to 3 additional heteroatoms selected from N, O and S, which is unsubstituted or substituted and which optionally contains one or two bridgehead atoms; R10and R11,which are the same or different, are selected from H, C1-C6 alkyl which is unsubstituted or substituted, -(CH2)nC3-C10 cycloalkyl and -(CH2)nAr; or R10 and R11 form, together with the nitrogen atom to which they are attached, a saturated five or six membered heterocyclic group which contains a nitrogen atom and 0 or from to 3 additional heteroatoms selected from O, S and N, which is unsubstituted or substituted and which is optionally fused to a benzene ring which is unsubstituted or substituted; n is the same or different when more than one is present within a given substituent group and is 0 or an integer of from 1 to 6; X is selected from -CN, -C02R9 and -NR10R11; R9 is the same or different when more than one is present within a given substituent group and is selected from -H, -QAr, -(CH2) nAr, C1-C6 alkyl which is unsubstituted or substituted and -(CH2) nC3-C10cycloalkyl, wherein the cycloalkyl moiety is optionally fused to a benzene ring which is unsubstituted or substituted; Q is C2-C6 alkenylene or alkynylene; and Ar is an unsaturated C6-C10 membered carbocyclic group or an unsaturated 5-11 membered heterocyclic group, which groups are unsubstituted or substituted; or a pharmaceutically acceptable salt thereof. These compounds have activity as inhibitors of MRP (multidrug resistant protein) and may thus be used to modulate multidrug resistance, for instance in potentiating the cytotoxicity of a chemotherapeutic agent.
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- Synthesis of substituted chrysenes and phenanthrenes
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3-Methylchrysene (9a), 2, 3, 9-trimethylchrysene (9b), 2, 6-dimethylphenanthrene (16a) and 1-isopropyl-4,6-dimethylphenanthrene (16b) have been synthesised in the following steps. β-(1-Naphthyl)ethyl bromide (6a), β-(6,7-dimethyl-1-naphthyl)ethyl bromide (6b), β-(3-methylphenyl)ethyl bromide (13a) and β-(2-isopropyl-5-methylphenyl)ethyl bromide (13b) are separately condensed with potassium salt of 1-carbethoxy-4-methylcyclohexane-2-one (1) to give respectively 7a, 7b, 14a and 14b. PPA cyclisation of 7a and 7b affords 8a and 8b while 14a affords 15a and 14b gives a mixture of 15b and 15c. Aromatisation of 8a and 8b leads to 9a and 9b and that of 15a gives 16a while 15b and 15c both produce 16b. The structures assigned are consistent with their spectral data.
- Mitra, Ashutosh,Ghoshe, Swati
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p. 785 - 789
(2007/10/03)
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