- Reaction of 3-nitro-1,2,4-triazole derivatives with alkylating agents. 1. Alkylation in the presence of alkali
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Alkylation of 3-nitro-1,2,4-triazole and 5-methyl-3-nitro-1,2,4-triazole with dialkyl sulfates or alkyl halides in the presence of alkali proceeds with a low selectivity for the alkylating agent with the formation of two regioisomers at the N(1) and N(2) atoms of the heterocycle. Depending on the reaction conditions the proportion of the N(2) isomer was 14.6-33.8%. 2005 Springer Science+Business Media, Inc.
- Sukhanov,Lukin
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- Tuning azoheteroarene photoswitch performance through heteroaryl design
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Photoswitchable compounds, which can be reversibly switched between two isomers by light, continue to attract significant attention for a wide array of applications. Azoheteroarenes represent a relatively new but understudied type of photoswitch, where one of the aryl rings from the conventional azobenzene class has been replaced with a fivemembered heteroaromatic ring. Initial studies have suggested the azoheteroarenes-the arylazopyrazoles in particular- to have excellent photoswitching properties (quantitative switching and long Z isomer half-life). Here we present a systematic computational and experimental study to elucidate the origin of the long thermal half-lives and excellent addressability of the arylazopyrazoles, and apply this understanding to determine important structure-property relationships for a wide array of comparable azoheteroaryl photoswitches. We identify compounds with Z isomer half-lives ranging from seconds to hours, to days and to years, and variable absorption characteristics, all through tuning of the heteraromatic ring. Conformation perhaps plays the largest role in determining such properties: the compounds with the longest isomerization half-lives adopt a T-shaped ground state Z isomer conformation and proceed through a T-shaped isomerization pathway, whereas the most complete photoswitching is achieved for compounds that have a twisted (rather than T-shaped) Z isomer conformation. By balancing these factors, we report a new azopyrazole 3pzH, which can be quantitatively switched to its Z isomer (1/2 = 74 d at 25 °C). Given the large tunability of their properties, the predictive nature of their performance, and the other functional opportunities afforded by usage of a heteroaromatic system, we believe the azoheteroaryl photoswitches to have huge potential in a wide range of optically addressable applications.
- Calbo, Joaquín,Weston, Claire E.,White, Andrew J. P.,Rzepa, Henry S.,Contreras-García, Julia,Fuchter, Matthew J.
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supporting information
p. 1261 - 1274
(2017/05/15)
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- Deacetylcolchicine deriv.
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Provided are 4-modified colchicine compounds and medicines using the same. Specifically provided are colchicine derivatives represented by general formula (1), salts thereof, and solvates of the same. In general formula (1), R1 is a halogen atom, a hydroxyl group, a nitro group, an amino group, or a mono-, di- or tri-fluoromethyl group; R2, R3 and R4 are each a methoxy group or a hydroxyl group, or alternatively R2 and R3, or R3 and R4 together represent a methylenedioxy group; R5 and R6 may be the same or different and are each a hydrogen atom, a C1-6 alkyl group, an arylalkyl group, a C2-6 alkenyl group, -COR7, -COOR8, -SO2R9, -CONR10R11, or -CSNR12R13, or alternatively R5 and R6 together with the nitrogen atom to which R5 and R6 are bonded may form a three- to seven-membered cyclic amino group; R7 is a C1-6 alkyl group or the like; R8 is a C1-6 alkyl group or the like; R9 is a C1-6 alkyl group or the like; R10 and R11 may be the same or different and are each a hydrogen atom, a C1-6 alkyl group, or the like; and R12 and R13 may be the same or different and are each a hydrogen atom, an alkyl group, or the like.
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Paragraph 0497
(2016/10/08)
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- Reactions of 3-nitro-1,2,4-triazole derivatives with alkylating agents. 2.* Alkylation of a neutral heterocycle by dimethyl sulfate
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The reaction of 3-nitro-1,2,4-triazole and 5-methyl-3-nitro-1,2,4-triazole with dimethyl sulfate leads to mixtures of N-mono- and N,N- dimethylnitrotriazolium compounds and products of the subsequent conversion of the latter, namely, N,N-dimethyl-1,2,4-triazol-5-ones.
- Sukhanov,Sakovich,Sukhanova,Lukin
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p. 994 - 998
(2007/10/03)
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- OXIDATIVE ALKYLATION OF AZOLES. I. REACTION OF N-CHLORO-3-NITRO-TRIAZOLES WITH METHYL IODIDE
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The reaction of methyl iodide with N-chloro-3-nitro-, and N-chloro-5-methyl-3-nitro-1,2,4-triazoles leads to the release of iodine and the formation of a mixture of compounds containing 3-nitro-1,2,4-triazoles unsubstituted at the nitrogen, the N-mono- and N,N-dimethylated derivatives (triazolium salts), and the products from their further transformations (1,4-dimethyl-5-triazolones).
- Pevzner, M. S.,Kurenkov, A. A.,Trubitsin, A. E.
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p. 1470 - 1475
(2007/10/02)
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