1- adamantyl derivatives

The formation of transient benzazetidinones (251) in the photolysis and thermolysis of benzotriazin-4-ones (250) is well established (76AHC215) and the highly hindered adamantyl derivative has actually been isolated from flash pyrolysis of 4-adamantylbenzotriazinone (73JCS(Pl)868). A second route to such hindered benzazetidinones involves cyclization of the iminoketene valence tautomer (252 R = Bu ), the latter being generated by deprotonation of the anthranilium salts (253) (71JA1543). 

Alkyldimethylphosphine-boranes 74 underwent enantioselective deprotonation employing (-)-sparteine/s-BuLi, followed by oxidation with molecular oxygen [91, 92] in the presence of triethyl phosphite (Scheme 12) to afford moderate yields of enantiomerically enriched alkyl(hydroxymethyl)methylphosphine-bo-ranes 76, with 91-93% ee in the case of a bulky alkyl group and 75-81% ee in the case of cyclohexyl or phenyl groups [93]. Except for the adamantyl derivative (in which the ee increased to 99%), no major improvement in the ee was observed after recrystallization. 

In the field of the dioxetanes not only a series of new compounds was synthesized and investigations of their thermal stability were performed — a particularly stable compound being the bis adamantyl derivative... 

A number of 2-alkyl-1,2,3-benzotriazinium salts similar to those described earlier have b n used in protective coatings and in the formulation of adhesives. 3-Alkyl-l,2,3-benzotriazin-4(3fl)-ones have been examined as potential irreversible inhibitors of chymotrypsin, and the 3-(l-adamantyl) derivative as a potential virus inhibitor. Some unspecified 1,2,3-benzotriazine derivatives have been tested as radioprotectant compounds (to complement the well-known mercap-toethylamine and mercaptoalkylisothiouronium compounds), but were found to be ineffective. ... 

Furukawa et al. (1) prepared a functional resin composition containing di-substituted adamantane, (I), which was used as a resist in semiconductor production processes. Monosubstituted analogs, (II), were prepared by Kodama et al. (2). Cyano-containing adamantyl derivatives, ( 1) and (IV), were prepared by Ito et al. (3) and Bae et al. (4), respectively, and used in preparing semiconductor devices. 

Tetra-, (V), and tri-substituted, (VI), adamantyl derivatives were prepared by Hatakeyama et al. (5) and used as components in semiconductors. 

One of the most common reasons for lowyields is an incomplete reaction. Rates of organic reactions can vary enormously, some are complete in a few seconds whereas rates of others are measured on a geological timescale. Consequently, to ensure that the problem of low yields is not simply due to low reactivity, reaction conditions should be such that some or all of the starting material does actually react. If none of the desired product is obtained, but similar reactions of related compounds are successful, the mechanistic implications should be considered. This situation has been referred to as Limitation of Reaction, and several examples have been given [32 ] the Hofmann rearrangement, for example, does not proceed for secondary amides (RCONHR ) because the intermediate anion 28 cannot form (Scheme 2.11). Sometimes, a substrate for a mechanistic investigation may be chosen deliberately to exclude particular reaction pathways for example, unimolecular substitution reactions of 1-adamantyl derivatives have been studied in detail in the knowledge that rear-side nucleophilic attack and elimination are not possible and hence not complications (see Section 2.7.1). 

Since the solvolysis reactions of bridgehead substrates are mechanistically uncomplicated (i.e. competing elimination is highly unlikely187 ns-H9) an(j backside solvent participation is impossible), they provide ideal models for limiting carbonium ion behavior. Adamantyl derivatives have become the substrates of choice for this purpose due to their availability and convenient reactivity. 

The rigid geometry of the adamantyl nucleus has also been utilized to quantitatively evaluate the stereoelectronic requirements of cyclopropylcarbinyl cations. The bisected conformation of the cyclopropyl cation, 97, is known to be preferred strongly relative to the perpendicular conformation, 98 280 The adamantyl derivate 99 incorporates a cyclopropyl carbinyl system locked in the... 

The 8,9-dehydro-2-adamantyl cation (101) incorporates a cyclopropylcarbinyl system in the preferred bisected (97) conformation. As would be expected, then, 8,9-dehydro-2-adamantyl derivatives (e.g.102) are highly... 

The following specialized terms will be used Adamantyl—derivatives of structure [1] ... 

An interesting feature of these results is that ethanol is less nucleophilic than water toward the adamantyl derivatives, in contrast to the normal nucleophilic order (Bentley et al., 1972). This inverted... 

In contrast to this 3-aza-l,2,4,6-tetraphosphaquadricyclanes 62a-62e are markedly more stable. The crystalline tert-butyl derivative melts at 76 °C, and the solid adamantyl derivative 62c was purified by bulb-to-bulb distillation at 140 °C and 10 bar <1998AGE1233, 2001ZN951>. 

ET-initiated alkylation of azines in the presence of alkyl halides has been found to occur under electrochemical conditions according to Scheme 43. Either alkylated dihydroheterocycles or the rearomatized products are obtained. As an example, electroreduction of quinoline in the presence of 1-bromoadamantane gives alkylated quinolines (10 % in position 2, 5 % in position 7) and 2-methyl- and 2-methoxyquinoline give the 7-adamantyl derivative in 20 and 23 % yield, respectively. 1,10-Phenanthroline gives bis(adamantyl) derivatives, whereas isoquinoline and phenanthridine give the 6-adamantyl-5,6-dihydro and the 9-adamantyl-9,10-dihydro derivatives, respectively [132]. Reaction with terr-butyl chloride also gives alkylated dihydroheterocycles [133]. Arylation has also been performed, e.g. in the synthesis of pyrazolophenanthridines (62, Scheme 44) [134]. 

Tsantih-Kakoulidou, A. Antoniadou-Vyza, A. Determination of the Partition Coefficients of Adamantyl Derivatives by Reversed Phase TLC and HPLC. In QSAR Quantitative Structure-Activity Relationships in Drug Design Alan R. Liss, Inc., 1989 71-74. 

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