- Access to α-Cyano Carbonyls Bearing a Quaternary Carbon Center by Reductive Cyanation
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Reductive cyanation of tertiary alkyl bromides using electrophilic cyanating reagent and zinc reductant was developed, providing various α-cyano ketones, esters, and carboxamides containing a nitrile-bearing all-carbon quaternary center in good to excellent yields under mild reaction conditions. The corresponding reaction mechanism involving in situ generated organozinc reagent and reactivity distinction was elucidated by density functional theory computation.
- Ren, Xinyi,Shen, Chaoren,Wang, Guangzhu,Shi, Zhanglin,Tian, Xinxin,Dong, Kaiwu
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supporting information
p. 2527 - 2532
(2021/05/05)
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- Reactivity of substrates with multiple competitive reactive sites toward NBS under neat reaction conditions promoted by visible light
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Regioselectivity of visible-light-induced transformations of a range of (hetero)aryl alkyl-substituted ketones bearing several competitive reactive sites (α-carbonyl, benzyl and aromatic ring) with N-bromosuccinimide (NBS) was studied under solvent-free reaction conditions (SFRC) and in the absence of inert-gas atmosphere, radical initiators and catalysts. An 8-W energy-saving household lamp was used for irradiation. Heterogeneous reaction conditions were dealt with throughout the study. All substrates were mono- or dibrominated at the α-carbonyl position, and additionally, some benzylic or aromatic bromination was observed in substrates with benzylic carbon atoms or electron-donating methoxy groups, respectively. Surprisingly, ipso-substitution of the acyl group with a bromine atom took place with (4-methoxynaphthyl) alkyl ketones. While the addition of the radical scavenger TEMPO (2,2,6,6-tetramethylpiperidin-1-yloxy) decreased the extent of α- and ring bromination, it completely suppressed the benzylic bromination and α,α-dibromination with NBS under SFRC.
- Grjol, Bla?,Jereb, Marjan
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p. 5235 - 5248
(2021/06/07)
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- Building Congested Ketone: Substituted Hantzsch Ester and Nitrile as Alkylation Reagents in Photoredox Catalysis
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For the first time, 4-alkyl Hantzsch esters were used to construct molecules with all-carbon quaternary centers by visible light-induced photoredox catalysis via transfer alkylation. Up to a 1500 h-1 turnover frequency was achieved in this reaction. Reactions of 4-alkyl Hantzsch nitriles as tertiary radical donors joined two contiguous all-carbon quaternary centers intermolecularly, and this chemistry was used to synthesize a common precursor of a class of hydroxysteroid dehydrogenase inhibitors.
- Chen, Wenxin,Liu, Zheng,Tian, Jiaqi,Li, Jin,Ma, Jing,Cheng, Xu,Li, Guigen
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supporting information
p. 12312 - 12315
(2016/10/07)
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- Discovery of 6-phenylpyrimido[4,5- B ][1,4]oxazines as potent and selective Acyl CoA: Diacylglycerol acyltransferase 1 (DGAT1) inhibitors with in vivo efficacy in rodents
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The discovery and optimization of a series of acyl CoA:diacylglycerol acyltransferase 1 (DGAT1) inhibitors based on a pyrimido[4,5-b][1,4]oxazine scaffold is described. The SAR of a moderately potent HTS hit was investigated resulting in the discovery of phenylcyclohexylacetic acid 1, which displayed good DGAT1 inhibitory activity, selectivity, and PK properties. During preclinical toxicity studies a metabolite of 1 was observed that was responsible for elevating the levels of liver enzymes ALT and AST. Subsequently, analogues were synthesized to preclude the formation of the toxic metabolite. This effort resulted in the discovery of spiroindane 42, which displayed significantly improved DGAT1 inhibition compared to 1. Spiroindane 42 was well tolerated in rodents in vivo, demonstrated efficacy in an oral triglyceride uptake study in mice, and had an acceptable safety profile in preclinical toxicity studies.
- Fox, Brian M.,Sugimoto, Kazuyuki,Iio, Kiyosei,Yoshida, Atsuhito,Zhang, Jian,Li, Kexue,Hao, Xiaolin,Labelle, Marc,Smith, Marie-Louise,Rubenstein, Steven M.,Ye, Guosen,McMinn, Dustin,Jackson, Simon,Choi, Rebekah,Shan, Bei,Ma, Ji,Miao, Shichang,Matsui, Takuya,Ogawa, Nobuya,Suzuki, Masahiro,Kobayashi, Akio,Ozeki, Hidekazu,Okuma, Chihiro,Ishii, Yukihito,Tomimoto, Daisuke,Furakawa, Noboru,Tanaka, Masahiro,Matsushita, Mutsuyoshi,Takahashi, Mitsuru,Inaba, Takashi,Sagawa, Shoichi,Kayser, Frank
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p. 3464 - 3483
(2014/05/20)
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- CF3CO2ZnEt-mediated highly regioselective rearrangement of bromohydrins to aldehydes
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A highly efficient and selective rearrangement reaction of bromohydrins to aldehydes mediated by CF3CO2ZnEt was described. The secondary and tertiary aldehydes were prepared under mild conditions in good to excellent yields (85-99%). The scope and limitations of this rearrangement process were also investigated.
- Wang, Zhihui,Li, Meiyi,Zhang, Wenqin,Jia, Jiangnan,Wang, Fei,Xue, Song
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supporting information; experimental part
p. 5968 - 5971
(2011/11/29)
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- NEW PHOTOINITIATORS
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The invention relates to novel photoinitators of formulae (I), (II), (III), (IV), (V) and (VI) wherein R1 and R2 are each independently of the other C1-C8alkyl; C1-C4alkyl substituted by OH, C1-C4alkoxy, -COO(C1-C8alkyl), (C1-C4alkyl)-COO-, -CN, benzyl, phenyl or by -N(R15)(R16); C3-C6alkerlyl, benzyl, -CH2-C6H4-(C1-C4alkyl) or phenyl; or R1 and R2 together are unbrarched or branched C2-C9alkylene or C3-C6-oxa- or -aza-alkylene; R3, R4, R5 and R6 are each independently of the others hydrogen, C1-C8alkyl, C3-C6alkenyl, benzyl, -CH2-C6H4-(C1-C4alkyl) or phenyl; R3 and R4 together and/or R5 and R6 together are unbranched or branched C2-C9alkylene; A is CI, Br, -O-R9, -N(R11)(R12) or -S-R18, A' is -O-, -NH- or -NR11-; A" is CI, Br, -O-R9, -N(R11)(R12) or -S-R18 or hydrogen, X is -O-R10 or -N(R13)(R14), n is an integer from 1 to 10, preferably an integer from 1 to 4, especially 1, 2 or 3; R7 is a linker; R8 is a bivalent C2-C3alkylele radical.
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Page/Page column 38-39
(2010/02/14)
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