- Strategy to Prepare 3-Bromo- and 3-Chloropyrazoles
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A general strategy to prepare substituted 3-bromo- and 3-chloropyrazoles is described. The three-step method involves condensation of crotonates or β-chloro carboxylic acids with hydrazines, followed by halogenation and oxidation. Several condensation and oxidation protocols were developed to enable preparation of a wide variety of 3-halopyrazoles with good to excellent yields and regiocontrol.
- Fox, Richard J.,Schmidt, Michael A.,Eastgate, Martin D.
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p. 2830 - 2839
(2018/03/09)
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- Synthesis of enantiomerically pure 2-heteroaromatic-substituted 1,2-amino alcohols from chiral tert-butanesulfinyl aldimines
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Nine R/S pairs of 2-heteroaromatic-substituted 1,2-amino alcohols were synthesized through 1,2-nucleophilic addition between chiral N-(tert-butylsulfinyl)imines and heteroaromatic carbanions. In most cases, the R S-isomer of N-(tert-butylsulfinyl)imines afforded the R amino alcohol from deprotection of the major diastereomer, and S S-imines afforded the S product. In general, this procedure allows for the preparation of a variety of enantiomeric pairs of 2-heteroaromatic-substituted 1,2-amino alcohols on a practical scale (>10 g) in two steps in good yields.
- Chen, Yantao,Goldberg, Frederick W.,Xiong, Jian,Wang, Shujun
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supporting information
p. 679 - 691
(2015/03/31)
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- HETEROCYCLIC COMPOUND
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The present invention provides an agent for the prophylaxis or treatment of autoimmune diseases (e.g., psoriasis, rheumatoid arthritis, inflammatory bowel disease, Sjogren's syndrome, Behcet's disease, multiple sclerosis, systemic lupus erythematosus etc.) and the like, which has a superior Tyk2 inhibitory action. The present invention relates to a compound represented by the formula wherein each symbol is as defined in the specification, or a salt thereof.
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Paragraph 0577
(2015/01/18)
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- Phototransposition of 1-Methylpyrazole. Deuterium, Methyl, and Fluorine Substitution
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1-Methylpyrazole (1) was observed to undergo photo-ring cleavage to 3-(N-methylamino)propenenitrile (17) and phototransposition to 1-methylimidazole (3).Although upon prolonged irradiation 17 is also converted to 3, the efficiency of the 1 -> 17 -> 3 pathway is low and cannot account for a significant fraction of 3 observed upon short-duration irradiation.Under these conditions, deuterium-labeling studies show that 1 phototransposes to 3 by the P4, P6, and P7 permutation patterns in a ratio of 4.8:6.5:1.0.These scrambling patterns are consistent with mechanims involving ring contaction-ring expansion (P4) and electrocyclic ring closure followed by one (P6) or two (P7) sigmatropic shifts of nitrogen.Methyl and fluorine substitution on the 1-methylpyrazole ring reduces reactivity via the P6 and P7 pathways.Thus, 1,5-dimethylpyrazole transposes by these pathways in a ratio of 3.5:1.8:1.0, whereas 5-fluoro-1-methylpyrazole isomerizes only by the P4 and P6 pathways in a ratio of 9.7:1.
- Pavlik, James W.,Kurzweil, Edyth M.
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p. 6313 - 6320
(2007/10/02)
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