Groups n-butyl

The C4H9 alkyl groups may be derived either from the unbranched carbon skele ton of butane or from the branched carbon skeleton of isobutane Those derived from butane are the butyl (n butyl) group and the 1 methylpropyl (sec butyl) group... 

However, very recent studies by Fish and his co-workers (467) with butyltin compounds showed that the primary, metabolic reaction is not Sn-C bond-cleavage but carbon hydroxylation of the n-butyl group. Using [l- C]tetrabutyltin in an in vitro study, the major, primary metabolite was identified as a 2-hydroxybutyltributyltin derivative that underwent a rapid /3-elimination reaction to afford 1-butene and a tri-butyltin compound (467). 

The condensed cycloparaffin rings crack yielding n-butyl groups, containing, in part, the 13C label in a terminal CHg position (signal at 14.0). 

Fig. 21 Calculated structure of an active species derived from Zr-FI catalyst 33 with /-Bu,Al/ Ph CBtCy j, cocatalyst system (polymer chain model n-butyl group). Reproduced with permission from Ishii et al. [26], Copyright 2002, Wiley-VCH.

In the reactions with trimethyltelluronium salts (al), alcohols with the stmcture RCH(-Bn)OH are formed as minor by-products (6-23%), resulting from the transference of the n-butyl group. 

The effect of the butyl side chains on the LCST s of copolymers of NIPAAM is interesting, especially in the case of the n-butyl copolymer. One hypothesis is that the n-butyl groups associate and precipitate more readily than the less flexible t-butyl groups do. This is consistent with the observation that poly-N-n-propyl acrylamide is insoluble at room temperature in water (3). 

The spectra observed for ethylene adsorbed on nickel—silica [75,78] show similar features to those found with platinum—silica. The major difference is the temperature range over which the various bands are observed with nickel—silica, the surface n-butyl groups are present at room... 

Alkanes and cycloalkanes. Obviously a variety of acyclic and cyclic hydrocarbon structures can be synthesized from the appropriate alkyl- or aryl-thiophenes (Scheme 46). The reaction is especially useful for the construction of macrocycles (Scheme 47). One of the most interesting applications of this reaction is in the synthesis of the chiral hydrocarbon butylethylmethylpropylmethane (210) (80JOC2754). The chiral acid (209) was the precursor, in which the thiophene was the potential n-butyl group. Raney nickel desulfurization, followed by standard manipulations to convert the acetic acid unit into an ethyl group, gave the hydrocarbon (210) (Scheme 48) this had [a]578 = -0.198°. It was established that... 

Bestian and Clauss proposed that the polymerization occured with isomerization on a cationic alkyltitanium species or one of its associated forms. Propagation by anionic and cationic species accounts for their results more easily. Most of the oligomer low molecular weight product was from anionic type propagation (Equation 8). However, the 7.8% of the dimer and the 30% of the trimer fractions were produced by cationic propagation of the n-butyl group (Equation 9). 

---