Alkyl compounds

Orally administered testosterone, and also derivatives that feamre a secondary hydroxyl group at C17, are rapidly deactivated in the liver. These agents, as a result, never attain therapeutically effective blood levels. This rapid inactivation can be avoided by adding an alkyl group at that position. The chemistry used for such additions generates a 17)8 -hydroxyl analogous to that present in testosterone. Much of the research on androstanes has as a result been focused on molecules that possess an alkyl group at Cn that substituent is most commonly methyl. 

I Alkyl Derivatives Many of the simpler modifications on ring A follow closely the analogous changes in the 17-desalkyl series. Many of those transformations were actually first applied to the 17-aIkyl compounds. 

Many enone systems readily undergo 1,3-dipolar addition reactions. This applies to steroids, as illustrated by the formation of the fused pyrazole 16-4 from reaction of the enone 16-2 with diazomethane. Pyrolysis of that pyrazole results in extrusion of nitrogen to leave behind a methyl group at position 1 (16-5). 

Examples of reactions that involve carbanion-mediated alkylations have thus far all involved the formation of an enolate that led to reaction at C2. Alkylation of 17-methyltestosterone, however, favors reaction at C4. Treatment of that enone, 14-1, with methyl iodide in the presence of the strong base potassium tcrt-butoxide leads to the formation of the 

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Synthesis This route has been carried out successfully (Rec. Trav. Chem., 1958, 77, 854). Note that no AICI3 is needed for Friedel-Crafts alkylation with easily formed t-alkyl compounds. 

Data for alkyl-benzenes are collected in table 9.1, and for substituted-alkyl compounds in table 9.2. 

Products are contaminated with more highly alkylated compounds, but less so than without the active metal. The phosphide can be generated from a Grignard or organolithium reagent. 

RTIX2 derivatives are covalent compounds, generally soluble in organic solvents. The aryl and vinyl derivatives are more stable than the corresponding alkyl compounds. This type of compound has been postulated to be an intermediate in many organic synthetic reactions involving thaUium(III) species. 

Metals and metalloids that form alkyl compounds, eg, methylmercury and methylarsenic acid, tributjltin, deserve special concern because these compounds are volatile and accumulate in cells they are poisonous to the central nervous system of higher organisms. Because methylmercury or other metal alkyls may be produced at a rate faster than it is degraded by other organisms, it may accumulate in higher organisms such as fish. Hg species are also reduced to elementary Hg which is soluble in water but lost by volatilization to the atmosphere (40). 

Ketones can be reduced by the Wolff-Kishner method to the corresponding alkyl compounds, or by sodium in ethanol to the corresponding alcohols. An alkali-catalyzed deacylation of 3-acetyl-6-methoxypyridazine 1-oxide occurs quantitatively on treatment with dilute sodium hydroxide. 

In the diaziridinimine field there is no sharp contrast between stable t-alkyl and unstable primary alkyl compounds. Both types are known as stable compounds (80H(14)1677). 

Such A-alkyl compounds are not known to be of any current application although fibres from a partially A-alkylated derivative of nylon 610 have been described. 

Manganese cyclopentadienyl tricarbonyl (as Mn) Marble/calcium carbonate Mercury (alkyl compounds) (as Hg)... 

Atid aie pioduced by passing carbon dioxide into tlie ether bolution of the magnesium alkyl compound. 

Monomeric alkyl compounds of the form MR3 have also been obtained for Sc and Y, where the alkyl groups are of the types Me3SiOH2 and Me300H2 which are bulky and contain no )3 hydrogen atoms (p. 926). 

Although compound 38 liberates the calculated amount of iodine, the completely alkylated compound 34 only gives traces of iodine. The... 

Alkyl-rest, n. alkyl residue, alkyl group, -sulfo-aSore, /. alkyl sulfonic acid, -verbindung, /. alkyl compound. 

Alkyl compounds can be synthesized by substitution, oxidative addition and insertion reactions... 

Water, which can be taken to a minimum by the use of molecular sieves, can produce a lactamide either through direct reaction with the aziridinone intermediate, or upon hydrolysis of oxazolidinone self-condensation products, previously obtained also in the presence of a strong non-nucleophilic base (H ) (ref. 17). The recently reported 0-self-alkylation compound H bears the (S,S)-configurations at the unreacted C-Br and newly formed C-0 bonds. The presence of bromine was expedient for the x-ray assessment of configuration at the two chiral centers of 11 which forms in high diastereoisomeric excess (ref. 5). 

Sulfinic acids can be prepared by reduction of sulfonyl chlorides. Though mostly done on aromatic sulfonyl chlorides, the reaction has also been applied to alkyl compounds. Besides zinc, sodium sulfite, hydrazine, sodium sulfide, and other reducing agents have been used. For reduction of sulfonyl chlorides to thiols, see 19-57. 

Various N-nitroso-AT-alkyl compounds undergo elimination to give diazoalkanes. One of the most convenient methods for the preparation of diazomethane involves base treatment of V-nitroso-V-methyl-p-toluenesulfonamide (illustrated above, with... 

This is intimately related to the nature of the solvent. If the solvent is nonpolar and lacks coordinating ability, then generally [known exceptions are the Pt(II) and Ir(III) complexes mentioned in Section B] the insertion will proceed via attack of L upon the alkyl compound ( 2 path), e.g.. Table I, reaction 6. 

D. G. H. Ballard Polymerisation by homogeneous transition metal alkyl compounds, pp. 213-264 (25). 

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