Dialkyl compounds

Additions of other nucleophiles to pyridopyrazines have been described in a number of cases for instance, Grignard reagents give 2,3-dialkyl compounds (398) (or 6-alkyl analogues with 2,3-diaryl compounds) (76BSF251), and other workers have also observed 6-addition <71CR(C)(273)1529). 

Upon methylation of /) -dehydroindolizidine (55), dialkylated compounds 115 and 116 are formed in addition to C-monomethylated product 114. Compound 115 is accessible also by methylation of 8-methyl-zJ -dehydro-quinolizidine (//i). 

Reactions of enamines with aluminum hydrogen dichloride (540,541) (UAIH4 and AICI3) or aluminum hydrogen dialkyl compounds (542) led to organoaluminum intermediates which could be hydrolyzed to tertiary amines or oxidized to aminoalcohols. The formation of olefins by elimination of the tertiary amine group has also been noted in these reactions. 

Homologation of the N-substituent beyond ethyl generally abolishes activity (22). N,N-dialkylation does not lead to active compounds, even with 3,4-meth-ylenedioxy substitution (197). It should be noted, however, that only a few N,N-dialkyl compounds have been clinically evaluated. N-alkylation also decreases in vitro serotonin receptor affinity (80). Certain N-propyl, N-cyclopropylmethyl, and N-allyl derivatives show weak antagonism against mescaline-induced disruption of swimming behavior in mice (50). 

Although N,N dialkyl compounds have very little activity, they are probably worth further investigation. 

Totally synthetic bilayers show liquid crystalline properties similar to those of lecithin bilayers (Nagamura et al., 1978 Kano et al., 1979). Bilayer formation has also been observed for dialkyl compounds with anionic head groups such as [2] and [3] (Kunitake and Okahata, 1978a Mortara et al., 1978), and with nonionic and zwitterionic head groups as in [4] and [5] (Okahata et al., 1978a). 

Treatment of cyclopropane 1 with one equivalent of dry BiCl3 in methylene chloride results in an exothermic reaction producing monoakylbismuth derivative 16 in 80% yield Eq. (19) [11]. Addition of another equivalent of the cyclopropane then affords the dialkylated bismuth species 17, which in turn reacts with BiCl3 to give the monoalkyl species. IR absorptions due to the carbonyl groups indicate the chelate structures shown. The two propionate moieties in the dialkylated compound 17 give rise to two distinctive carbonyl bands in the IR spectrum,... 

Among the group 16 elements, mostly non-metallic ones like TeCl were examined [11]. The reaction with TeCU proceeds in a stepwise manner giving the mono-alkyltellurium and the dialkyl compound in accordance with the stoichiometry of the reagents Eq. (21). As in the case of tin and bismuth, the second alkylation is much slower than the first and the dialkyl species could not be alkylated any further. 

The original activity referred to is the activity of the optically active sec-butylmercuric bromide used to make the dialkyl compound. The actual result was that, under several different sets of conditions, the product had one-half of the original activity, demonstrating retention of configuration. 

In general, alkylation of ambident S,N-nucleophilic heterocycles gives predominantly, if not exclusively, S-alkylated products. In some cases, however, N-alkylation follows S-alkylation to give N,S-dialkylated compounds. 

Whereas Al alkyls and alkyl halides are completely hydrolyzed in water, dialkyl compounds of Ga, In, and Tl give well-characterized compounds in aqueous solution. Thallium gives very stable ionic derivatives of the type R2T1X (X = halide, SO4-, CN , NO3, etc.) which resemble the isoelectronic mercury dialkyls R2Hg in being unaffected by air and water. The [TlMe2]+ ion is linear, but does not form an aquo complex like Me2Ga(H20)2. 

A novel ionic liquid methodology for pyrrole C-alkylation is described (Equation 136) <20050L1231>. The pyrrole alkylation is achieved with various simple alkyl halides (1-bromopentadecane, l-(bromomethyl)-, l-(3-chloropropyl)- and l-(3-iodopropyl)benzenes, 2-(2-bromoethyl)- and 2-(3-bromopropyl)naphthalenes) and mesylates (3-phenylpropyl-, l-methyl-3-phenylpropyl-, 2-(2-naphthyl)ethyl- and 3-(2-naphthyl)propyl methanesulfonates) selectively at C(2)- and C(5)-positions in good yields with minimal by-products under relatively mild conditions in various ionic liquids. 2-(3-Phenylpropyl)pyrrole 569 was synthesized from pyrrole and l-bromo-3-phenylpropane in a mixed solvent system, [Bmim][SbF6] and MeCN, in 81% yield at 115°C for 44h with 5% yield of dialkylated compound. 

Another route to lanthanide dialkyls is a metathesis reaction. Lanthanide dihalides supported by a bulky monoanionic ancillary ligand, such as pentamethylcyclopentadienyl and related derivatives [4], P-diketiminato and guanidinato groups [49, 50], and so on, are generally used as the starting materials. A variety of lanthanide dialkyl compounds, including methyl compounds have been prepared and structurally characterized via successive metathesis reactions (Figure 8.11). 

Rapid addition of methyl iodide causes the formation of a significant amount of 2,3-dialkylated compound and 2-methylenecyclopropanone acetal (by isomerization of the olefin). 

Of the various possible types of -substituted sulfamoyl (sulfamyl) chlorides, the dialkyl compounds are of particular interest because they serve as intermediates in the syntheses of substituted sulfamides (synthesis 28) and of certain of their derivatives (synthesis 29). The dialkyIsul-famoyl chlorides have been prepared by the reaction of sulfuryl chloride with an appropriate amine or its hydrochloride, " by the treatment of secondary 7V-chloroamines with liquid sulfur dioxide, and by the reaction of dialkyl-aminosulfinic acids with chlorine in carbon tetrachloride. Although either of the first two procedures can be recommended in terms of convenience and yield, the availability of starting materials normally dictates that the first be used. It is of interest that treatment of sulfuryl chloride with either ammonia or ammonium chloride in terms of this procedure does not give the parent sulfamoyl chloride, H2NSO2CI. This compound is obtained in an altogether different way. ... 

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