DR ANTHONY MELVIN CRASTO,WorldDrugTracker, helping millions, A 90 % paralysed man in action for you, I am suffering from transverse mylitis and bound to a wheel chair, With death on the horizon, nothing will not stop me except God
DR ANTHONY MELVIN CRASTO Ph.D ( ICT, Mumbai) , INDIA 25Yrs Exp. in the feld of Organic Chemistry,Working for GLENMARK GENERICS at Navi Mumbai, INDIA. Serving chemists around the world. Helping them with websites on Chemistry.Million hits on google, world acclamation from industry, academia, drug authorities for websites, blogs and educational contribution
n
Showing posts with label 1-Dimethyl-3-(pyridin-2-yl)urea. Show all posts
Showing posts with label 1-Dimethyl-3-(pyridin-2-yl)urea. Show all posts

Friday, 28 October 2016

Solvent- and halide-free synthesis of pyridine-2-yl substituted ureas through facile C-H functionalization of pyridine N-oxides



Solvent- and halide-free synthesis of pyridine-2-yl substituted ureas through facile C-H functionalization of pyridine N-oxides

Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC02556K, Paper
Valentin A. Rassadin, Dmitry P. Zimin, Gulnara Z. Raskil'dina, Alexander Yu. Ivanov, Vadim P. Boyarskiy, Semen S. Zlotskii, Vadim Yu. Kukushkin
A solvent- and halide-free atom-economical synthesis of practically useful pyridine-2-yl substituted ureas utilizes pyridine N-oxides and dialkylcyanamides.


Solvent- and halide-free synthesis of pyridine-2-yl substituted ureas through facile C–H functionalization of pyridine N-oxides


*
Corresponding authors
a
Institute of Chemistry, Saint Petersburg State University, Universitetskaya Nab. 7/9, 199034 Saint Petersburg, Russia
E-mail: v.rassadin@spbu.ruv.kukushkin@spbu.ru
b
Ufa State Petroleum Technological University, Kosmonavtov 1, Ufa, Bashkortostan, Russia
c
Research Park SPbSU, Center for Magnetic Resonance, Saint Petersburg State University, Universitetskaya Nab. 7/9, 199034 Saint Petersburg, Russia
Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC02556K






























A novel solvent- and halide-free atom-economical synthesis of practically useful pyridine-2-yl substituted ureas utilizes easily accessible or commercially available pyridine N-oxides (PyO) and dialkylcyanamides. The observed C–H functionalization of PyO is suitable for the good-to-high yielding synthesis of a wide range of pyridine-2-yl substituted ureas featuring electron donating and electron withdrawing, sensitive, or even fugitive functional groups at any position of the pyridine ring (63–92%; 19 examples). In the cases of 3-substituted PyO, the C–H functionalization occurs regioselectively providing a route for facile generation of ureas bearing a 5-substituted pyridine-2-yl moiety.



1,1-Dimethyl-3-(pyridin-2-yl)urea







1,1-Dimethyl-3-(pyridin-2-yl)urea (4a)3 : From pyridine 1-oxide (1a) (95.0 mg, 1.00 mmol) and dimethylcyanamide (2a) (105 mg, 1.50 mmol), compound 4a (147 mg, 89%) was obtained according to GP1 as a yellow oil, which was then crystalized in the freezer to give pale yellow solid, m.p. = 42.6–43.5 °C, lit.4 m.p. = 44–47 °C (EtOAc/hexane), Rf = 0.25 (EtOAc). 1H NMR (400 MHz, CDCl3): δ = 3.00 (s, 6 H, NCH3), 6.88 (ddd, J = 7.3, 5.0, 0.9 Hz, 1 H), 7.30 (br. s, 1 H), 7.60 (ddd, J = 8.5, 7.3, 1.9 Hz, 1 H), 8.02 (dt, J = 8.5, 0.9 Hz, 1 H), 8.14 (ddd, J = 5.0, 1.9, 0.9 Hz, 1 H) ppm. 13C NMR (101 MHz, CDCl3): δ = 36.3 (2 С, CH3), 113.0 (CH), 118.1 (CH), 138.0 (CH), 147.3 (CH), 152.8 (C), 154.8 (C) ppm. NMR data are consistent with previously reported.3 HRMS (ESI), m/z: [M + H]+ calcd. for C8H12N3O+ : 166.0975; found: 166.0977.


////////////