Imidazole -1-trityl

Imidazole, l,2,5-trimethyl-4-nitro-mass spectra, 5, 359 Imidazole, 1-trimethylsilyl-reactions, 5, 454 with acid chlorides, 5, 391 Imidazole, 1-trimethylstannyl-reactions, 5, 454 Imidazole, 2,4,5-trinitro-reactions, 5, 98 synthesis, 5, 395 Imidazole, 1,2,4-triphenyl-UV spectra, 5, 356 Imidazole, 1,2,5-triphenyl-UV spectra, 5, 356 Imidazole, 2,4,5-triphenyl-chemiluminescence, 5, 381, 406 irradiation, 5, 433 oxidation, 5, 376, 406 photochemical addition reactions, 5, 421 synthesis, 5, 467, 483 UV spectra, 5, 356, 357 Imidazole, 1-trityl-rearrangement, 5, 377 Imidazole, vinyl-Michael addition, 5, 437 polymers, 1, 281 Imidazole, 1-vinyl-reactions, 5, 450 thermal rearrangement, 5, 450 Imidazole, 2-vinyl-oxidation, 5, 437 Imidazole, l-(D-xylofuranosyl)-synthesis, 5, 491 277-Imidazole, 2,2-dialkyl-rearrangement, 5, 422 277-Imidazole, 4,5-dicyano-2,2-dimethyl-synthesis, 5, 472... 

ALKENES Alkyl diphenyl phosphonates. o-Chloroallyllithium. Chlorotrynethyl-silane-Sodium iodide. Grignard reagents. Otganocuprates. Triphenylphosphine-lodoform-Imidazole. Trityl tetrafluoro-borate. 

Trityl Chloride Imidazole Thiophosgene Hydrogen Sulfide Acetic Acid... 

Butenolide 231 was obtained by a procedure that did not involve a pyrolytic step (237). Thus, the 5-trityl ether 223c was converted into the thioxocar-bonate 230 upon treatment with A,A -thiocarbonylbis(imidazole). Raney nickel effected the conversion of 230 into 231. 

The synthesis of losartan potassium (1) by the process research chemists at Merck is outlined in the following (Griffiths et ak, 1999 Larsen et al., 1994). Phenyltetrazole (8) is protected as the trityl phenyltetrazole 9 (Scheme 9.3). Ortho-lithiation of 9 followed by quenching with triisopropyl borate afforded boronic acid 10 after treatment with aqueous ammonium chloride. Reaction of glycine (11) with methyl pentanimidate (12) in a methanol/water mixture yielded (pentanimidoylamino) acetic acid (13), which underwent a Vilsmeier reaction with phosphorous oxychloride in DMF followed by hydrolysis to give imidazole-4-carbaldehyde 14 in moderate yield. 

Solid phase attachment of histidine-containing peptides by anchoring the imidazole ring to trityl resins has been developed for combinatorial library preparation of diketopiperazines <99TL809>. Histidine, histamine, and urocanic acid are edl imidazole-containing molecules that have been attached to a trityl-type resin to allow their application to combinatorial chemistry <99TL2825>. 

Mercaptopropionic acid has been used as a scavenger in detritylation of protected imidazoles. In the purification, A-21 tertiary amine-functionalized resin 23 sequestered excess of this acidic reagent, the tritylated byproduct formed from it, and TFA (reaction 6).32... 

Histidine and histamine derivatives, as well as other imidazoles, have been successfully immobilized by N-tritylation of the imidazole ring with trityl chloride resin [534] (Entry 2, Table 3.29 see also Section 15.8) or with 2-chlorotrityl chloride resin [535-537]. Histidine can also be linked to insoluble supports as the N-dinitrophenyl deriva-... 

The trityl-, dimethylsulfamoyl- and the SEM-groups work best for NH protection in the C5 functionalisation of the imidazoles. Protective groups for the C2 position such as the... 

Tiitylation silylation. This amine is an efficient catalyst for tritylation of hydroxyl groups with trityl chloride and triethylamine. The method permits use of solvents other than pyridine, such as DMF or CHjClj. The same conditions can be used to prepare t-butyldimethylsilyl ethers. Yields are comparable to those obtained with imidazole (4, 57-58). A further advantage is that the selectivity for reaction with a primary hydroxyl group is enhanced in this new procedure. ... 

The sodium salts of imidazoles are so readily hydrolyzed that they are only stable in such media as ethanol or liquid ammonia. Sparingly soluble salts, e.g. silver salts, are stable in aqueous medium, and have been utilized for isolation of imidazoles and in the formation of some 1-substituted derivatives, e.g. 1-trityl, 1-glycosyl (Section 4.07.1.3.8). Mercury salts of imidazole are believed to adopt a linear polymeric structure, and results of studies of thallium and tin derivatives suggest that they, too, are polymeric, at least in the solid state. Stable organotin derivatives of imidazoles are non-explosive and often stable in boiling water. 

The reactions of 2-lithio- and 2-sodio-imidazoles and -benzimidazoles are not particularly novel. The compounds do, however, prove a means of introducing a variety of functional groups into the 2-position of the heterocyclic ring. Such metalation reactions at C-2 can only occur readily when there is no alternative site for the metal. Therefore, only N-substituted imidazoles are of synthetic utility, and it may be necessary to select an N-substituent which can be removed later. For this reason, benzyl (removed by reductive or oxidative methods), benzenesulfonyl (removed by ammoniacal ethanol), trityl (hydrolyzed by mild acid treatment) and alkoxymethyl (easily hydrolyzed in acid or basic medium) groups have proved useful in this context. A typical reaction sequence is shown in Scheme 136 <78JOC438l, 77JHC517). In addition, reactions with aldehydes and ketones (to form alcohols), with ethyl formate (to form the alcohol) and with carbon dioxide (to form carboxylic acids) have found application (B-76MI40701). 

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