................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
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Saturday, 4 February 2017
Example 1 - Preparation Of Compound 1 (4-(3-(methylsulfonyl)phenyl)-l-propylpiperidin-4-ol)
4-(3-(methylthio)phenyl)-1 - 4-(3-(methylsulfonyl)phenyl)- propylpiperidin-4-ol 1 -propylpiperidin-4-ol
To a suspension of 4-hydroxy-4-(3-(methylthio)phenyl)-l-propylpiperidin-l-ium chloride (140g, 348mmol) in 710mL water were added 1.5g sodium tungstate dihydrate, and the mixture was heated to 45°C. 102mL of 33%H202 were added in 20min at 45-55°C. The suspension dissolved after 20mL addition. The solution was then stirred at 48-51°C for 30min after which HPLC showed no more starting material and two new peaks, one at RT 2.68min (82.3%) and the other at RT 3.66min (11.8%). After additional stirring for 2hr and 45min HPLC showed that the peak at RT 2.68min decreases to 7.5% and the peak at RT 3.66min increases to 88.5%. After another 45min the mixture was cooled to 20°C and into the reaction mixture were added 500mL toluene and 150mL ~5M NaOH. After stirring for 5min the mixture was poured into separator funnel. The solubility of the product in toluene is low. Majority of the product settled as very viscous liquid layer in the bottom. The water phase (and most of the product) was separated, toluene phase was washed successively with 5% Na2S03 solution and with brine and dried on MgSC>4. The water phase was extracted with 500mL DCM. The organic phase was washed successively with 5% Na2S03 solution and water and was dried on MgSC>4. Both extracts were concentrated on a rotavapor. 500mL of heptanes were added to both residues, and the suspensions were stirred at room temperature for 2 hrs. The precipitates were filtered, washed with heptane and dried. From the DCM extract were obtained 83.8g of white powder, purity by HPLC 98.8%, IH-NMR assay 97.9%. (From the toluene extract were obtained 13.7g of white powder, purity by HPLC 98.0%).
NMR Identity Analysis of Compound 1
Compound 1 :
The following data in Tables 2 and 3 was determined using a sample of 78.95 mg Compound 1, a solvent of 0.55 ml DMSO-D6, 99.9 atom%D, and the instrument was a Bruker Avance ΙΠ 400 MHz.
Table 2: Assignment of 'H NMRa-c
a The assignment is based on the coupling pattern of the signals, coupling constants and chemical shifts.
b Weak signal.
0 Spectra is calibrated by the solvent residual peak (2.5 ppm).
Table 3: Assignment of 13C NMRa'b
a The assignment is based on the chemical shifts and 1H-13C couplings extracted from HSQC and HMBC experiments.
b Spectra is calibrated by a solvent peak (39.54 ppm)