Piperidine Derivatives with a Sulfur-Containing Function in the 4- Position¹

Abstract

NOTES 641from the evaporation of the mixed solvents was then crystallized from methanol, yielding 0.9 g. (47.4%) of pure product, melting at 171-172". And. Calcd. for C18H17NaO:: C. 66.87; H, 5.26; N, 13.00. Found: C, 66.70; H, 5.40; N, 13.11. $?,6-Bis(4'-ethoxy-2'-pyridyl)-4-ethoxypy~dine. To a cooled solution of 0.68 g. of sodium in 91 ml. of anhydrous ethanol was added 2.2 g. of 2,6bis(4'-nitro-2'-pyridyl)-Pnitropyridine. After stirring for 4 hr. at 60-65", solution waa nearly complete. The filtered alcoholio solution was evaporated to dryness using an aspirator and extracted with chloroform. After evaporation to a volume of 45 ml.; 9 ml. of phosphorus trichloride was added and the mixture refluxed for 3 hr. It was then poured on ice and made alkaline. The precipitate obtained, which was insoluble in ether and chloroform was dried and again treated with chloroform and phosphorus trichloride as before. After again pouring on ice and making alkaline, the product dissolved in ether and waa recovered by evaporation of the mixed solvents; yield, 0.8 g. (42.1%) of pure product melting a t 157-158'. Anal.Calcd. for C,1HpaNnOt: C, 69.04; H, 6.30. Found: C, 68.96; H, 6.49. 2,6-Bis(4'-chloro-b'-pyridyl)-4-chloropyridine.To a SUSpension of 2 g. of 2,6-bis( 4'-nitro-2'-pyridyl)-bnitropyridine in 20 ml. of glacial acetic acid a t 60' was added 12 ml. of acetyl chloride. After heating for 1 hr. on the steam bath, an additional 4 ml. of acetyl chloride was added and heating continued for 1 hr. The mixture was poured on ice and the solution neutralized with sodium bicarbonate. The crude oxide precipitating after separation by filtrat,ion and drying was suspended in 35 ml. of chloroform. To the cold mixture was added 4.5 ml. of phosphorus trichloride. After standing for 1 hr., it was refluxed for one hour on the steam bath, and then poured on ice and made alkaline. The resulting precipitate, after drying, was crystallized from benzene yielding 1.2 g. (75.0%) of product, m.p. 210-211°. An analytical sample melted a t 212-213'.

Dipalladium and diplatinum bis(µ-alkanethiolato) complexes with a planar M2S2ring

“…As a check on the validity of this treatment we have also refined a Pd: Pt disorder ratio for each of the metal atom sites in the pure homonuclear complexes 3 and 4. Refinement gives occupancy factors of 0.998 2(61) and 1.003 3(3) for Pd in 3, and of 1.013 65(5) and 1.010 76 (6) for Pt in 4. These factors, which are all essentially unity but have extremely small estimated standard deviations, indicate that the occupancy factors obtained for 5 are reliable, but that their standard deviations are rather underestimated.…”

Thioesters for the in vitro evaluation of agents to image brain cholinesterases

“…The solvent was removed in vacuo to yield a colourless liquid which was distilled (BP: 168-172°C, lit. BP = 62°C at 0.8mm 30 ); to yield the product as a clear colourless oil (21.22 …”

Piperidine Carboxylic Acid Derivatives of 10H-Pyrazino[2,3-b][1,4]benzothiazine as Orally-Active Adhesion Molecule Inhibitors

“…Mercaptopiperidine 17 was synthesized using the method of Barrera as shown in Chart 3. 17) Benzyl piperidone 16 was converted to its dithiol, which on reduction with sodium borohydride gave 17. Condensation of 17 with ethyl bromoacetate followed by removal of the benzyl group using 1-chloroethyl chloroformate (ACECl) afforded compound 4i.…”