4 -Nitro-4-piperidino

Nucleophilic substitution has been used for the preparation of many thiophenes. For instance, 2-phenylthio-3,4-dinitro-5-piperidino-thiophene (155) has been prepared " through stepwise reaction of (150) with different nucleophiles. Nitrothienols and derivatives of them have been obtained from halogenated nitrothiophenes. " Allyl ethers have been prepared by the reaction of 5-chJoro-4-nitro-2-acetylthiophene, 3-nitro-2-chlorothiophene, and 2-nitro-3-bromothio-... 

As to the electron-withdrawing substituents, the activating effect of a nitro group in the piperidino-dechlorination of 2-chloropyridine involves factors of 7.3 x 10 and 4.6 x 10 from the para and ortho positions, respectively. An ortho-cyano group was found to be... 

The ortho indirect deactivating effect of the two methyl groups in 2,6-dimethyl-4-nitropyridine 1-oxide (163) necessitates a much higher temperature (about 195°, 24 hr) for nucleophilic displacement of the nitro group by chloride (12iV HCl) or bromide ions N HBr) than is required for the same reaction with 4-nitropyridine 1-oxide (110°). With 5-, 6-, or 8-methyl-4-chloroquinolines, Badey observed 2-7-fold decreases in the rate of piperidino-dechlorination relative to that of the des-methyl parent (cf. Tables VII and XI, pp. 276 and 338, respectively). 

It was discovered that 3-iiitro-2-piperidiiio-, 3-iiitro-7-piperidiiio-, and 7-A -diethaiiolamiiio-3-iiitro-l, 8-iiaphthyridiii-2(lH)-oiies and 2-diethanol-amino-7-piperidino-3-nitro-l,8-naphthyridine showed remarkable aetivity to inhibit human platelet aggregation in vitro indueed by araehidonie aeid, eollagen, and ADR Tliis aetivity was eomparable to papaverine, dipyridamole, and ibuprofen (94EJMC735). 

Auf ahnliche Weise wird 4-Chlor-2-piperidino-l-nitro-benzol zum Benzimidazol-Derivat cyclisiert4 ... 

Chlor-2-nitro-l -piperidino- 692 4-Chlor-l-nitroso- 478 Chlorsulfonyl-methyl- 680 Deutero- 623... 

Nitro-l-methylthio- 684 Nitro-thiocyanat- 635 2-Nitro-l-thiocyanat- 680, 692 4-Nitro-l-thiocyanat- 685, 687 2-Nitro-l-[penten-(l)-yl-(2)]- 698 4-Nitro-l-phenoxy- 688 4-Nitro-l-phenylthio- 684 2-Nitro-l-piperidino- 696 2-Nitro-l-(propyl-butyl-amino)- 696 Nitro-seleno- 558... 

Piperidino-7- 7-toluenesulfonaniidoqumoxalme (1, Q = R = H) gave a separable mixture of 5-nitro-8-piperidino-6-p-toluenesulfonamido- (1, Q = H, R = NO2) and 6-nitro-5-piperidino-7-p-toluenesulfonamidoquinoxaline (1, Q =... 

Nitro-8-piperidino-6-p-toluensulfonamidoquinoxaline (79, R = Ts) gave 5-nitro-8-piperidino-6-quinoxalinamine (79, R = H) [95% H2SO4, 100°C ( ),... 

Recently195, the hydrogen bond basicity scale (p.K hb as logarithm of the formation constant of 4-fluorophenol/base complexes in carbon tetrachloride, equilibrium 21) has been measured for several nitro derivatives (nitromethane, nitrobenzene, IV-nitrocamphorimine, 2-nitropropane, 4-nitro-o-xylene, 4-nitroanisole, lV,./V-diethyl-4-nitroaniline, l-dimethylamino-2-nitroethylene, l-piperidino-2-nitroethylene) ... 

Complex 1 1 is considered the only complex present, but the hydrogen bond may be either two (76) or three center (77). Nitroenamines are more prone to complex with 4-fluorophenol than the nitroanilines and they form the strongest hydrogen bond presently known for nitro-bases. In particular, l-piperidino-2-nitroethylene (78) and 1-dimethylamino-2-nitroethylene (79) (both in E form) present a hydrogen bond basicity comparable to that of tributylamine. 

Similar results were then found for piperidino-debromination of various nitro-activated five-membered ring heterocycles103. The existence of such linear Hammett plots for ortho-substituted substrates was interpreted as a peculiar feature of five-membered ring heterocycles, where steric effects of substituents ortho to the site of the nucleophilic attack are minimized13. 

Wagner-Meerwein rearrangements occur also when arylsulfenyl chlorides or the mixtures R2NCI + SO3 (R = piperidino, morpholino) add to norbomadiene 393196,197. An addition of 2-nitro- (NBSC) or 2,4-dinitrobenzenesulfenyl chloride to the polyenes 395-397 in AcOH and under doping conditions (AcOH, with LiClO/f) is accompanied by Wagner-Meerwein rearrangements (equations 145-147)198. Thus, new types of struc-... 

Eine chinoide Zwischenstufe analog III (S. 225) wird auch bei der Saure-katalysierten ther-mischen Umlagerung von N-Cyclohexyl-105 oder N-Piperidino-2-nitro-anilin102 postuliert. 

So erhalt man bei der Reaktion von 4-Nitro-benzhydrazid mit (Chlor-methylthio-methylen)-piperidinium-chlorid entweder 5-(4-Niiro-phenyl)-2-piperidino- oder 2-Methylthio-5-(4-nitro-phenyl )-l, 3,4-oxadiazol2is ... 

Nitro-phenyl)-2-piperidino-l,3,4-oxadiazol248 9,1 g (50 mmol) 4-Nitro-benzhydrazid, 80 ml trockenes Pyridin und 12,0 g (56 mmol) (Chlor-methylthio-methylen)-piperidinium-chlorid erhit/t man 2 h auf 70°. AnschlieBend verdiinnt man mit 4%iger Natronlauge, filtricrt und kristallisiert aus Ethanol um Ausbeute 7,3 g (54%) Schmp. 176°. 

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