Ada, adamantyl

Cp pentamethylcyclopentadienyl Tmp 2,2,6,6-tetramethylpiperidine Dipp 2,6-di(iso-propyl)phenyl Trip 2,4,6-tri(iso-propyl)phenyl Mes 2,4,6-trimethylphenyl Mes 2,4,6-tri(tert-butyl)phenyl Ada adamantyl dmap 4-(dimethylamino)pyridine Tms trimethylsilyl (SiMe3)... 

Adamantonium Ions. There exists a single theoretical study for ada-mantonium ions.850 Mota and co-workers have found three isomeric structures (490-492) and two van der Waals complexes (1-adamantyl cation+ H2 and 2-adamantyl cation + H2) [MP2(full)/6-31G level]. The C—H bond lengths in the 3c-2e interactions in ion 490 are 1.276 and 1.266 A and in ion 491 are 1.266 and 1.280 A. The C-adamantonium ion (492) has nonequivalent C—H bond distances (1.191 and 1.294 A) and the C—C bond distance is 2.348 A. Interestingly, the 2-adamantyl cation + H2 complex shows a nonclassical bonding nature similar to the... 

Similar results are obtained with 2-adamantanol which rearranges to 1 -ada-mantanol (> 98 %) at 28°C in sulfuric acid. An equilibrium mixture containing small amounts of 2-adamantanol is rapidly achieved fromeither direction67 6 K This isomerization is one of the mechanistic bases for the preparation of ada-mantanone by the reaction of adamantane with sulfuric acid at 77°C (see Section V.A.l) 57> 67> 691. The Koch-Haaf carboxylation of 2-adamantanol similarly results in predominant 1-adamantyl carboxylic acid formation unless highly dilute reaction conditions are employed 57> 7°). 

It should be pointed out, however, that the pharmacological effects of ada-mantyl moieties are not general. The adamantyl substituted naphthoquinones, 111, for example, are found to be slightly less effective antimalarials than the... 

The transition structures for the hydrolysis reactions of methyl, /-butyl, and ada-mantyl chlorides in the gas phase and in water were calculated using the B3LYP/6-31-G(d) level of theory and the PCM solvation model.82 In the gas phase, backside attack is strongly favoured for the methyl chloride reaction and slightly favoured for the t -butyl chloride reaction. Frontside attack is favoured for the adamantyl chloride... 

CH2)] and [M( -Cp)2(OCH=CH2)2], which are thermally qnite stable and show no tendency to eliminate aldehyde to form ketene complexes. [NbCl N(C6H3Me2-3,5)(ada-mantyl) 3] reacts with thf to give [Nb N(C6H3Me2-3,5)(adamantyl) 3(OCH=CH2)] . ... 

The 1-adamantyl (1-Ada) esters exhibit increased acid stability if compared to the tert-butyl esters.These amino acid esters are prepared by reaction of the amino acid tosylates with adamantan-l-ol and dimethyl sulfite in boiling toluene. Removal of the adamantyl ester is effected by neat TFA within 1 hour or TFAyCH2Cl2 (1-2) within 15 hours. N-Terminal Boc groups are selectively cleaved with 4 M HCl in anhydrous dioxane (rt, 25 noin) in the presence of the 1-adamantyl ester. 

The cysteine 5-(tert-butyl) derivative is obtained by reaction of cysteine with isobutenef ° l or teri-butyl acetatef under acid catalysis. Under both of these reaction conditions, the carboxy group is esterified and has to be deprotected by TFA treatment. A more general procedure, applicable for the synthesis of both 5-(tert-butyl) (tBu) and 5-(l-adamantyl) (1-Ada) derivatives (Scheme 10), is based on S-alkylation of cysteine with the teri-alcohols under acidic conditions.The related A -Boc and A -Fmoc derivatives are obtained by standard procedures. 

With a similar intention, 1-adamantyl and 2-adamantyl residue-based protecting groups were developed. (3-1- and (3-2-Adamantylaspartates,P Y-(2-adamantyl)glutamate,P A -(2-ada-mantyloxycarbonyl)lysine,P l A -(2-adamantyloxycarbonyl)histidine,P Af -(l-adamantyl-... 

Abbreviations used in tables include Ada = 1-adamantyl boro-AA-OH = boronic acid analogue of specified amino acid (aa) Cbz = benzyloxycarbonyl CMK = chloromethylketone EIM = enzyme inhibitor of monocytes -NA = p-nitroanilide ND = not determined NR = not reactive MeO-Suc = methoxy succinoyl Met(O) = methionine sulphoxide Pic = picolinyl PPE = porcine pancreatic elastase SLPI = secretory leukocyte proteinase inhibitor TFMK = trifluoromethylketone Z = benzyloxycarbonyl. 

Arylhydrazone von 3-(l-Adamantyl)-3-chlor-acrolein und 3-(l-Adamantyl)-3-chlor-2-methyl-acrolein geben beim Erhitzen in einem Phosphorsaure/Essigsaure-Gemisch661 oder in Phos-phorsaure6625-( l-Adamantyl)-l-( 2,4-dinitro-phenyl)-(41 % Schmp. 163,5 165,5°), 5-( 1-Ada-mantyl)-l-(2,4-dinitro-phenyl)-4-methyl- (54% Schmp. 199,5-200,5°)661 bzw. 5-( 1-Adaman-tyl)-1-phenyl-lH-pyrazol (48% Schmp. 135-136°)662 ... 

A suspension of dehydrated MgBig in dry ether added at 0° to a soln. of 1-ada-mantyl-3- err-butyl-2-aziridinone in the same solvent, stirred 48 hrs. at room temp., then hydrolyzed with 2 N HCl -> N-l-adamantyl-2-bromo-3,3-dimethyl-butyramide. Y 90%. I. Lengyel, R. V. Mark, and C. A. Troise, Synth. Commun. 1, 153 (1971). 

Trofimov, B.A., E.Yu. Schmidt, N.V. Zorina et al. 2008. A short-cut from 1-acetyl ada-mantane to 2-(l-adamantyl)pyrroles. Tetrahedron Lett 49 4362-4365. 

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