Imidazole chemical structure

The chemical structure of biotin (hexahydro-2-oxo-IH-thieno [3,4-d] imidazol-4-valeric acid) is shown in Fig. 1. Of the eight stereoisomers, only d-(+)-biotin occurs naturally and is biologically active. 

Figure 8.9 The chemical structure of imidazole and imidazoline, together with some well-known derivatives...

The chemical structure of histamine has similarities to the structures of other biogenic amines, but important differences also exist. Chemically, histamine is 2-(4-imidazolyl)ethylamine (Fig. 14-1). The ethylamine backbone is a common feature of many of the amine transmitters (e.g. dopamine, norepinephrine and serotonin). However, the imidazole nucleus, absent from other known transmitters, endows histamine with several distinct chemical properties. Among these is prototypic tautomerism, a property that permits it to exist in two different chemical forms (Fig. 14-1). The tautomeric properties of histamine are thought to be critical in the... 

The three part so-called cocktail used to treat HIV positive patients typically comprise a proteinase inhibitor, such as those discussed in Chapter 1 a nucleoside-based reverse transcriptase inhibitor, such as those in Chapter 6, and a non-nucleoside inhibitor of reverse transcriptase (NNRTI). Most of the compounds in the first two classes share a good many structural features with other agents in the class. Chemical structures of the various NNRTIs on the other hand have little in common. Capravirine (103), is notable in the fact that it fails to include any of the fused ring systems that provide the nucleus for other compounds in this class. Chlorination of 3-methylbutyraldehyde (94) provides one of the components for building the imidazole ring. For bookkeeping purposes, the condensation of 94 with 0-benzyl glyoxal and ammonia can be... 

Fig. 10. Chemical structures of kinase inhibitors, (a) p38 inhibitor SB203580 (4-[5-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-3H-imidazol-4-yl]pyridine). (b) EGFR inhibitor (N-(3-(6-(3-(trifluoromethyl) phenylamino) pyrimidin-4-ylamino) phenyl) cydopropanecarboxamide). The dashed line indicates hydrogen-bonding interactions with the hinge.

Fig. 12 Chemical structures of mesogenic 3 1 discotic complexes based on complexes of benzoic acid derivatives (21 or 24) with a a fris(imidazolinc) 22 or b a benzotri(imidazole) 23 core...

Isoconazole. Tike econazole, both the chemical structure and the clinical indications of this imidazole derivative (Fig. 2, 7c) closely resemble those of miconazole. It is available as a vaginal tablet (300 mg isoconazole nitrate per tablet). In some countries isoconazole [27523-40-6] is also available as a cream for dermatological use and as a cream and ovules for treatment of vaginal candidosis. 

Figure 4.5-1. Chemical structures of activated PEGs for amine conjugation (a) PEG-dichlorotriazine (b) PEG-tresylate (c) PEG-aldehydes (d) PEG-succinimidyl succinate (e) PEG-imidazole carbonate (f) PEG-phenyl carbonate (g) PEG-succinimidyl carbonate (h) PEG-benzotriazole carbonate and (i) PEG-active ester.

Alkaloids can be divided into different t q3es according their pure chemical structures pointing first at the alkaloid base, a basic chemical nucleus. The following are basic types of alkaloids acridones, aromatics, carbo-lines, ephedras, ergots, imidazoles, indoles, bisindoles, indolizidines, manza-mines, oxindoles, quinolines, quinozolines. quinolizidines, phenylisoquinolines, phenylethylamines, piperidines, purines, pyrolidines, pyrrolizidines, pyrro-loindoles, pyrydines, sesquiterpenes, simple tetrahydroisoquinolines, stereoids, tropanes, terpenoids, diterpenes, and triterpenes. 

Our motivation for investigating thioamide derivatives, which potentially can form N-H... S interactions, arises from the presence of the -N(H)-C(=S)- residue, and derivatives thereof, in several dmgs [20], see Scheme 6.2 for chemical structures of these species. Thus, the antithyroid drugs 6-n-propyl-thiouracil (I) and l-methyl-3//-imidazole-2-thione (II, Methimazole , also marketed as Tapazole ) feature the -N(H)-C(=S)- functional group [21]. Hyperthyroidism may be treated with 3-methyl-2-thioxo-4-imidazoline-l-carboxylate (III, Carbimazole ) which is metabolised in vivo to the active form, known as Methimazole [22]. Anti-tubercular agents containing the thioamide residue and which inhibit mycolic acid synthesis include 2-ethyl-thioisonicotinamide (IV, Ethionamide ) and its -propyl derivative (Prothionamide ) [23-25]. 

Scheme 6.2 Chemical structures of drugs containing the -N(H)-C(=S>- residue and derivatives thereof ( ) 6-n-propyl-thiouracil, (11) 1-methyl-3H-imidazole-2-thione (Methimazole or Tapazole ), (Ilf) ethyl 3-methyl-2-sulfanylidene-imidazole-1 -carboxylate (Carbimazole ) and (IV) 2-ethylpyridine-4-carbothioamide (Ethionamidd )...

Chemical structure (Figure 12). Biotin (hexahydro-2-oxo-lH-thieno[3,4-d]imidazole-4-pentanoic acid). Biologically active analogs biocytin (e-N-biotinyl-L-lysine), oxybiotin (S substituted by O). 

Fig. 9 Chemical structures of the heterocyclic compounds a Isoxazole, b Imidazole, c Indole, d Quinoline, and e Triazole...

Pig. 2 Chemical structure and names of representative diradical compounds presenting large second hyperpolarizabilities. l,2-bisfphenalen-l-ylidene)ethene (1), 1,2-bisfphenalen-l-ylidene)-ethane (2), 5-indaceno[l,2,3-c / 5,6,7-c d ]diphenalene (IDPL, 3), 1,4-bis-(imidazole-2-ylidene)-cyclohexa-2,5-diene (BI2Y, 4). 

Chiral recognition, enantioselectivity, and influence of room temperature CILs (RTIL) synthesized from 1-methyl imidazole and chloromethyl menthyl ether on excited-state photophysics of (5)-Ai-methyl-2-pyrrolidinemethyl 2(5)-(6-methoxy-2-naphthyl)propionate [(5,5)-NPX-PYR] was recently investigated using a fluorescence lifetime [114]. The chemical structures of the CILs and chiral analytes used for the lifetime study are shown in Fig. 21, left. The lifetime fluorescence decay of [(5,5)-NPX-PYR] in RTIL chiral environment is shown in Fig. 21, right. 

Figure 19.7 Chemical background, (a) Schematic chemical structure of native silaffin-IA (pH 5). (Adapted from Ref. [56].) (b) Silicatein topology and the key role of the hydroxy group of serine-26 and the imidazole side chain of histidine-165 in the proposed mechanism for silicatein-mediated catalysis. (Adapted from Ref. [1001.)...

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