59886-90-7Relevant articles and documents
1H, 13C and 15N NMR spectral and theoretical studies of some methyl and alkylamino derivatives of 4-halopyridine N-oxides
Laihia,Puszko,Linnanto,Kolehmainen
, p. 73 - 78 (2006)
Nine new and three earlier known 4-halogen (Cl and Br) substituted pyridine N-oxides have been prepared and their 1H, 13C and 15N NMR chemical shifts assigned based on PFG 1H, X (X=13C and 15N) HMQC and HMBC experiments as well as the comparison with our earlier results for substituted pyridine N-oxide derivatives. The 15N resonances of the pyridine nitrogen are 27-40 ppm more shielded in 4-halo-2-alkylamino-6-methyl-5-nitropyridine N-oxide than in parent 4-halopyridine N-oxide. According to quantum chemical ab initio HF/6-311G** calculations the amino tautomer of 4-chloro-2- methylamino-6-methyl-5-nitropyridine N-oxide is more stable than its imino form. Using B3LYP/6-311G** optimized structures both 13C and 15N shifts were calculated by density functional B3LYP/6-311G ** CSGT methods for the amino and imino tautomers as well as for the dimeric structure for 4-chloro-2-methylamino-6-methyl-5-nitropyridine N-oxide. The 15N NMR and DFT calculations suggest the prevailing of the dimeric amino form for one congener, which is further supported by ESI-TOF MS data.
Synthesis and green metric evaluation of 2-(chloromethyl)-3-methyl-4-(methylsulfonyl)pyridine
Gilbile, Rohidas,Bhavani, Ram,Vyas, Ritu
, p. 930 - 936 (2017/05/29)
2-[[(2-pyridinyl) methyl] sulfinyl]-1H-benzimidazoles are the prominent motif's that belong to the class of prazoles. These are used in the treatment of gastroesophageal reflux disease (GERD) ulcers and other gastric acid related diseases. The present article describes the modified synthesis of 2-chloromethyl-4-methanesulfonyl-3-methyl pyridine (an intermediate utilized in the synthesis of Dexlansoprazole). The advantages of this modification involves (i) N-oxidation of 2,3-lutidine with catalytic quantity of RuCl3 in presence of oxygen (ii) One pot synthesis of 2,3-dimethyl-4-(methylthio) pyridine-N-oxide using 30% NaSH, methyl iodide and tetra butyl ammonium hydroxide (iii) Oxidation of methythio pyridine-N-oxide with 30% H2O2 followed by N-deoxygenation with RuCl3.H2O to produce 2,3-dimethyl-4-(methylsulfonyl)pyridine (iv) Chlorination of the penultimate step using trichloroisocyanuric acid to obtain the desired 2-chloromethyl-4-methanesulfonyl-3-methyl pyridine. Furthermore, green metrics assessment was calculated for the above modified scheme based on the parameters viz., atom economy (AE), reaction mass efficiency (RME) and E-factor. It was observed that, in case of step 4 (oxidation of thiomethyl pyridine-N-oxide), the E-factor value is very less 3.2 which is indicative of less waste generation, when compared to the various steps that are involved in the synthesis.
Development of a scalable and safe process for the production of 4-chloro-2,3-dimethylpyridine- N -oxide as a key intermediate in the syntheses of proton pump inhibitors
Waser, Mario,Obermueller, Roland,Wiegand, John Matthias,Schiek, Wolfgang,Fierz, Hans,Skranc, Wolfgang
experimental part, p. 562 - 567 (2011/07/08)
2-(Pyridin-2-ylmethanesulfinyl)-1H-benzimidazole-based drugs belong to the most prominent and successfully applied proton pump inhibitors. To fulfill the demand for a flexible and safe procedure for the synthesis of early-stage intermediates which are known to possess a strong exothermal decomposition potential, we have developed a high-yielding telescoped procedure for the synthesis of a key intermediate in the synthesis of these drugs. This strategy turned out to be highly reproducible in laboratory as well as on pilot-plant scale. As the starting material, as well as some of the intermediates, shows a highly exothermal decomposition potential, extensive safety investigations were undertaken. The whole process was adapted in a safe and reliable manner based on the outcome of this systematic approach. Considering these precautions, no safety issues were observed, neither in the laboratory nor in the pilot plant.