Pyridine-containing compounds

Within the series of compounds containing the (25 ,52 )-dimethylpiper-azine, there is not always a preferred benzhydryl epimer. The epimer with R stereochemistry at this position was certainly preferred for BW373U86 with respect to delta opioid receptor agonism, but for other compounds there was little difference in the activity of the epimers. For example, pyridine containing compounds 35 and 36 have similar potencies at the delta and mu opioid receptors (Table 4). As demonstrated by the activity of related compounds (see Sec. 2.3), the stereochemical features of (+)-BW373U86 are not essential to the delta opioid receptor pharmacophore. 

Nicotinamide N-methyltransferase (NNMT) methylates serotonin, tryptophan, and pyridine-containing compounds such as nicotinamide and nicotine. Phenylethanolamine N-methyltransferase (PNMT)... 

In H NMR study of the reaction between epoxy- and pyridine-containing compounds, the lreas of signMs in the ranges 6 = 8.57 -6.88 ppm, 9.70-8.50 ppm, and 9.70-8.80 ppm, which characterize the protons of the lromatic ring of pyridine and HepPyCl, decrease 1.5 times more rapidly than the reduction mobility due to increase in... 

One of the motivations for studying new pyridine reactivity is to find efficient routes to biologically active pyridine-containing compounds. A number of interesting imidazo[l,2-a]pyridine deritatives were found to have promising activity. For example, a couple of imidazo[l,2-rt]pyridine-... 

El-Sayed et al. [26] reported synthesis and antimicrobial evaluation of several quinoline and pyrimidoquinoline derivatives. The pyridine containing compounds were exerted strong antibacterial and antifungal activities, especially when a methoxyl group was located in the 7-position of quinoline nucleus. 

Tetrahydrofurfuryl alcohol reacts with ammonia to give a variety of nitrogen containing compounds depending on the conditions employed. Over a barium hydroxide-promoted skeletal nickel—aluminum catalyst, 2-tetrahydrofurfur5iarnine [4795-29-3] is produced (113—115). With paHadium on alumina catalyst in the vapor phase (250—300°C), pyridine [110-86-1] is the principal product (116—117) pyridine also is formed using Zn and Cr based catalysts (118,119). At low pressure and 200°C over a reduced nickel catalyst, piperidine is obtained in good yield (120,121). 

Although acetonitrile is one of the more stable nitriles, it undergoes typical nitrile reactions and is used to produce many types of nitrogen-containing compounds, eg, amides (15), amines (16,17) higher molecular weight mono- and dinitriles (18,19) halogenated nitriles (20) ketones (21) isocyanates (22) heterocycles, eg, pyridines (23), and imidazolines (24). It can be trimerized to. f-trimethyltriazine (25) and has been telomerized with ethylene (26) and copolymerized with a-epoxides (27). 

Detoxifica.tlon. Detoxification systems in the human body often involve reactions that utilize sulfur-containing compounds. For example, reactions in which sulfate esters of potentially toxic compounds are formed, rendering these less toxic or nontoxic, are common as are acetylation reactions involving acetyl—SCoA (45). Another important compound is. Vadenosylmethionine [29908-03-0] (SAM), the active form of methionine. SAM acts as a methylating agent, eg, in detoxification reactions such as the methylation of pyridine derivatives, and in the formation of choline (qv), creatine [60-27-5] carnitine [461-06-3] and epinephrine [329-65-7] (50). 

Alcohols 4-(4-Nitrobenzyl)- pyridine Amino compounds, esters and ethers do not interfere, but phenols and acids as well as epoxides, olefins and substances containing labile halogen probably do. [7]... 

In practical terms, it is invariably a nitrogen atom that is protonated in salt formation. This always leads to a downfield shift for protons on carbons both alpha and beta to the nitrogen concerned. In alkyl amines, the expected shifts would be about 0.7 and 0.3 ppm respectively. Remember that some heterocyclic compounds (e.g., pyridine) contain nitrogen atoms that are basic enough to protonate and comparable downfield shifts can be expected (Spectrum 5.9). 

As mentioned above the 1,1-organoboration reaction is reversible, and exchange is slow on the NMR timescale. This statement is in agreement with the chemical behavior of equilibrated mixtures of products. Thus, treatment of silicon borahomoadamantane derivative 92 with bis(trimethylstannyl)ethyne leads to the tin-containing compound 93 and liberation of bis(trimethylsilyl)ethyne (Scheme 44). With pyridine, the equilibrium is moved toward 1-boraadamantane completely due to the complexation <2001JOM(620)51>. 

Mo2(0R)6 compounds in hydrocarbon solvents rapidly polymerize acetylene to a black metallic-looking form of polyacetylene. Propyne is polymerized to a yellow powder, while but-2-yne yields a gelatinous rubber-like material (45). The detailed nature of these polymers is not yet known and the only molybdenum containing compounds recovered from these polymerization reactions were the Mo2(0R)6 compounds. When the reactions were carried out in the presence of pyridine/hexane solvent mixtures, simple adducts Mo2(0R)6(py)2(ac) were isolated for R = i-Pr and CH2-t-Bu, and ac = HCCH, MeCCH and MeCCMe (45,46). 

Several pyridine containing ligands of this type have been reported by Toftlund [2]. A combination of two aliphatic and four imine nitrogen functions seems to provide a ligand field at the crossover point. A versatile class of ligands of this type is based on aliphatic diamines substituted with four alkylpyridine groups. The simplest compound of this type is tetrakis(2-pyri-dylmethyl)-l,2-ethanediamine (tpen) (18). 

Pyridine-containing tricyclic compounds have been produced via a sequence consisting of a Suzuki reaction and a subsequent annulation. Gronowitz et al. coupled 2-formylthienyl-3-boronic acid with 3-amino-4-iodopyridine. The resulting adduct spontaneously condensed to yield thieno[2,3-c]-l,7-naphthyridine 59 [47]. They also synthesized thieno[3,4-c]-l,5-naphthyridine-9-oxide (60) in a similar fashion [48]. Neither the amino nor the N-oxide functional group was detrimental to the Suzuki reactions. 

In a sequence analogous to the Suzuki reaction and annulation described in section 4.2.4, pyridine-containing tricyclic compounds have also been prepared via the Stille reaction and a ... 

A combination of column adsorption chromatography on basic alumina and GC of the eluate served for characterization of the trace fraction of nitrogen-containing compounds in hydroprocessed naphtha. These were subdivided into groups of four types, namely pyridines, pyrroles (the most abundant), anilines and indoles125. 

Schulten et al. [16] identified the following N-containing compounds in NH-N fractions separated from several soils by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) pyrrole (la), methyl pyrrole (lb), pyridine (IVa), methylpyridine (IVb), indole (Via), and benzothiazole (XI). The Roman numerals refer to the chem-... 

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