3-Methyl-imidazole 1-oxide

Histamine is rapidly degraded by oxidative de-samination by the diaminooxidase histaminase, acetylation of the NH2-group, methylation of the ring and oxidation of the methylhistamines by the mono-aminoxidase. The main metabolites are the N-methyl-imidazole acetic acid and the imidazole acetic acid. Histamine interacts with at least four different specific receptors Hi to H4 (see Table 1). 

Omeprazole 5 -Methoxy-2- [(4 -methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinylj -17/-benzimidazol O-methylation, imidazole ring formation using thiourea, A-oxidation, nucleophilic displacement, A-methylation, S -oxidation... 

Der Austausch des Sauerstoff-Atoms in 1-substituierten Imidazol-3-oxiden durch Nukleophile verlauft unter Angriff des Nukleophils in 2-Position. So erhalt man z. B. aus 1-Benzyl-4,5-dimethyl-imidazol-3-oxid mit Kaliumcyanid/Dimethylsulfat I-Benzyl-2-cyan-4,5-dime thy l-imidazol (65%), mit Phosphoroxychlorid l-Benzyl-2-chlor-4,5-dimethyl-imidazol (72%) bzw. mit Butindisaure-dimethylester l-Benzyl-2- (1,2-dimethoxycarbonyl-2-oxo-ethyl)-4,5-dimethyl-imidazol (83%)962. Analog wird l-Benzyl-5-methyl-imidazol-3-oxid mit z.B. Kaliumcyanid/Dimethylsulfat zu l-Benzyl-2-cyan-5-methyl-imidazol (75%) umgesetzt962. 

Direct arylation of methyl imidazole with 2,7-dichloronaphthyridine leads to a potentially tetradentate and practically tridentate bis-carbene ligand on a naphthyridine scaffold [363]. Reaction of the bis-imidazolium salt with silver(l) oxide in the usual way yields a linear trinuclear silver carbene complex with this tris-bridging hgand (see Figure 3.115). 

Even a rod-like backbone derived from acetylene is conceivable and has been realised by Liu et al. [367] starting from l,4-dichlorobutin-2. The usual reaction with methyl imidazole and subsequent reaction with silver(l) oxide and carbene transfer to gold(I) [Au(SEtj)Cl] makes the dimeric silver(I) and gold(l) complexes accessible featuring argentophilic and aurophilic interactions, respectively. 

Different metal oxides (silica, alumina, and titania) are utilized as solid catalysts in the high-temperature ( 400°C) acylation of 2-methyl-imidazole 38 with AAN under a nitrogen stream (Scheme 4.27).i 4-Acetyl-2-methylimidazole 39 is produced in 65% yield in the presence of silica. The method is applied to the large-scale preparation of acylated imidazoles variously substituted on the heteroaromatic ring. 

Once released, histamine is rapidly metabolized in vivo (based on products from radiolabeled histamine administered intradermally) to nearly inactive metabolites by two major pathways N-methylation, and oxidation (Fig. 37.3). Methylation (S-adenosylmethionine), which is catalyzed by the intracellular enzyme N-methyltransferase, yields an inactive metabolite. A portion of the N-methylated metabolite is oxidized sequentially via monoamine oxidase and then via aldehyde oxidase to the corresponding N-methylimidazole acetic acid. Histamine also is oxidized to imidazole acetic acid by diamine oxidase (histaminase). A small amount of this acid intermediate is converted to the corresponding ribotide, an unusual metabolite (5). 

Similar experiments with PpNiR together with time-resolved FTIR showed significant differences." Nitrite bound to heme d and was rapidly reduced to form an EPR-detectable ferrous NO-heme d complex with oxidized heme c. The rate constant for electron transfer was estimated to be 500s. In a slower phase FTIR showed development of a band at l,913cm formed with a rate constant of 38 s . The energy of this band is consistent with a heme-Fe -NO" species, and close to those of model compounds of ferric heme d with NO and A-methyl imidazole." " ... 

Methyl imidazole Pigment violet 19 Synox HG-5040 Zinc Oxide Grade AZO 77H... 

Myverol 18-99. See Glyceryl oleate Myverol 18-99K. See Rapeseed glyceride Myverol P-06. See Propylene glycol stearate 2MZ. See 2-Methyl imidazole MZO-25. See Zinc oxide N299 Carbon Black, N375 Carbon Black See Carbon black... 

C12 dibasic acid Corfree M2 Corfree M3 DDDA 211-748-4 Alkateric PB AMPHOSOL CDB Cetyl betaine DeTAINE PB Lonzaine 16S Lonzaine 16SP Mackam CET Mi ratal ne BET-P-30 Product BCO 211-750-5 Antiox S Carstab DSTDP Cyanox STOP Distearyl thiodipropionate Evanstab 18 Hostanox SE 2 Irganox PS 802 Lankromark DSTDP Lowinox DSTDP PAG DSTDP PAG DXTDP Seenox DS Vanox DSTDP 211-756-8 Diamyl ether 211-759-4 Oleyl acetate 211-765-7 Imicure AMI-2 2-Methyl imidazole 211-772-5 Phenylsilane 211-774-6 Pyridine-N-oxide 211-776-7 Ancamine 1770 DCH-99... 

This is achieved by methylation and oxidation. In manunals, histamine is inactivated in two main ways— methylation of the imidazole ring effected by histamine A/-methyltransferase (HMT) and oxidative deamination of the primary amino group catalyzed by diamine oxidase (DAO)—to form A-methylhistamine and... 

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