Its Methyl Derivatives

Submitted by JOHN E. DRAKE, BORIS M. GLAVINCEVSKI, RAYMOND T. HEMMINGS.+ and H. ERNEST HENDERSON  

The position of iodosilane and iodotrimethylsilane in the heavy salt conversion series1,2 is such that iodosilane and its methylated analogues may be used as sources for the [(CH3) SiH3. ] - (n = 0-3) groups in the preparation of a wide variety of silicon halides 3 pseudohalides, 6 chalcogenides,s,7,s and group V derivatives.9 

Iodosilane has been prepared by the cleavage of phenylsilane10 or chloro-phenylsilane11,12 with hydrogen iodide, and by the reaction of monosilane with hydrogen iodide in the presence of a catalytic amount of aluminum triiodide.4 The latter method has been extended to prepare the methylated iodosilanes.5,13 Iodotrimethylsilane has also been prepared by the cleavage of trimethylphenyl-silane with iodine.14 

We describe herein the synthesis of iodosilane by the reaction of phenylsilane with hydrogen iodide and the preparation of the methylated iodosilanes, namely (CH3) SiH3 I (n = 0-3), by the reaction of the parent hydride with hydrogen 

The reaction flask is similar to that described in the preceding procedure. 

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Pyridine and its methyl derivatives, (2), (3), and (4), undergo amination with sodium amide at the 2-position eg, 2-anTino-3-methylpyridine [1603-40-3] and 2-anTino-5-methylpyridine [1603-41 -4] from (3) (eq. 3). This Chichibabin reactionis most important for introduction of a 2-amino substituent, which may be replaced readily by many other groups (18). 

Although the UV spectra of pseudouracil , in comparison with some of its methylated derivatives, suggested that it might be a mixture of the dioxo form (58) and a hydroxyoxo form (64AJC567) and NMR data seemed to uphold this in general terms 66JOC175), it now seems clear on extended criteria that the betaine (59) is probably the main contributor in solution <66JCS(B)565). 

There is also evidence for stable 3,4-adducts from the X-ray analysis of 2-amino-4-ethoxy-3,4-dihydropteridinium bromide, the nucleophilic addition product of 2-aminopteridine hydrobromide and ethanol (69JCS(B)489). The pH values obtained by potentiometric titration of (16) with acid and back-titration with alkali produces a hysteresis loop, indicating an equilibrium between various molecular species such as the anhydrous neutral form and the predominantly hydrated cation. Table 1 illustrates more aspects of this anomaly. 2-Aminop-teridine, paradoxically, is a stronger base than any of its methyl derivatives each dimethyl derivative is a weaker base than either of its parent monomethyl derivatives. Thus the base strengths decrease in the order in which they are expected to increase, with only the 2-amino-4,6,7-trimethylpteridine out of order, being more basic than the 4,7-dimethyl derivative. 

Isoxazole dissolves in approximately six volumes of water at ordinary temperature and gives an azeotropic mixture, b.p. 88.5 °C. From surface tension and density measurements of isoxazole and its methyl derivatives, isoxazoles with an unsubstituted 3-position behave differently from their isomers. The solubility curves in water for the same compounds also show characteristic differences in connection with the presence of a substituent in the 3-position (62HC(17)1, p. 178). These results have been interpreted in terms of an enhanced capacity for intermolecular association with 3-unsubstituted isoxazoles as represented by (9). Cryoscopic measurements in benzene support this hypothesis and establish the following order for the associative capacity of isoxazoles isoxazole, 5-Me, 4-Me, 4,5-(Me)2 3-Me> 3,4-(Me)2 3,5-(Me)2 and 3,4,5-(Me)3 isoxazole are practically devoid of associative capacity. 

The relative basicity and acidity of isothiazole and its methyl derivatives have been compared by IR spectroscopy (77MI41702). The isothiazoles, dissolved in inert solvents (e.g. CCI4, CS2) containing traces of butanol (a proton donor), interact with the butanol OH... 

When the rates of hydration of pteridine and its methyl derivatives are plotted against pH, a similar V-shaped curve (Fig. 5) is obtained. Results for a limited series of rate measurements on the hydration of pteridine, measured polarographically, accord with these values. 

An initial study of the infrared spectrum of oxindole purported to show the presence both of the hydroxy (78) and of the oxo forms (79), and, indeed, chemical evidence led to the same conclusion. On the basis of later infrared work, however, oxindole and its derivatives were considered to exist more or less completely in the oxo form, and this conclusion is supported by ultraviolet spectroscopic data, i.e., by comparison of the spectrum of the parent compound with those of its methyl derivatives. " The infrared spectrum of... 

The oxazaborolidines are easily prepared by heating ephedrine with borane dimethyl sulfide or the appropriate boronate ester. The aluminum reagent C is obtained by mixing ephedrine and trimethylaluminum. Borolidinc A is superior to its methyl derivative B and to the aluminum analog C. The diastereomeric borolidine obtained from borane and (S,S)-pseu-doephedrine failed to show any cnantioselectivity25. A variety of aromatic aldehydes can be enantioselectively alkylated in the presence of A, however, with heptanal the enantioselectivity is poor25. 

De la Mare et al.260 measured the rates of chlorination of biphenyl, a wide range of its methyl derivatives, and anisole in acetic acid at 25 °C. Second-order rate coefficients (104 2) were biphenyl (6.40), 2-methylbiphenyl (3.20), 3-methyl-biphenyl (820), 4-methylbiphenyl (30.0), 2.2 -dimethylbiphenyl (4.40), 3.3 -dimethylbiphenyl (2,630), 4,4 -dimethylbiphenyl (70.0), 2,6 -dimethylbiphenyl (1,130), 3,4,3, 4 -tetramethylbiphenyl (19,300), anisole (12.5 x 104), and these results showed very clearly the effect of steric inhibition of resonance between the phenyl rings through the presence of ortho methyl groups260. Similar (but rather more emphatic) results were obtained262 in chlorination of the /-butyl derivatives for which the corresponding rate coefficients were 2-/-butylbiphenyl (1.0) 4-/-butylbiphenyl (25.7), 2,2 -di-/-butylbiphenyl (1.8), 4,4 -di-/-butylbiphenyl (70.0). 

There is little doubt that the C-C distance in the benzene ring retains in its methyl derivatives the value 1.39 A. found for benzene itself.19 The main question regarding these substances is whether the distance from methyl carbon to ring carbon is determined by the usual single-bond radius, having thus the value 1.54 A., or whether... 

Tamura etal.2 described only briefly in their paper on dihydropyran derivatives that 6,8-dioxabicyclo[3.2.1]octan-7-one 53 and its methyl derivative underwent polymerization in the presence of a large amount of boron trifluoride etherate to give polymers with molecular weights of several hundreds. 

Durene, pentamethyl benzene and hexamethyl benzene have usually been prepared from benzene or one of its methylated derivatives by the Friedel-Crafts synthesis.1 Durene has been made from bromine derivatives of methylated benzenes by the Fittig reaction.2 It has also been obtained in 20 per cent yield by passing methyl alcohol and acetone vapors over heated alu-... 

Difructose anhydride II reacts with one mole of per-iodic acid. Hydrolysis of its methyl derivative indicates that two different trimethyl-D-fructoses are formed whose combined specific rotations in water amount to between + 20° and + 30°. If we assume that this anhydride, like the other two derived from inulin, is made up of D-fructofuranoses, the facts that have been mentioned allow only three possible structures for this anhydride. 

Although phenanthrene is noncarcinogenic, some of its methylated derivatives exhibit significant activity as mutagens (52,53). The 1,2- and 3,4-dihydrodiols of phenanthrene were first synthesized by Jerina et al. (54) by a method involving reduction of the corresponding quinones with LiAlH. However, the yields in the rein Polycyclic Hydrocarbons and Carcinogenesis Harvey, R. ... 

Jacobson et al. (1955) noted that the toxic actions of hydrazine and its methylated derivatives were similar all are respiratory irritants and convulsants. However, monomethylhydrazine also induced severe intravascular hemolysis in dogs. 

Witkin, L.B. 1956. Acute toxicity of hydrazine and some of its methylated derivatives. AMA Arch. Ind. Health 13 34-36. 

Scheme 6.101 Intermediacy of 1,2,4,5-cycloheptatetraene (506) and its methyl derivative 509 in the thermolysis of diethynylcyclopropanes.

Scheme 6.113 Formation of heptafulvalene (522), its methyl derivative 556 and its dimethyl derivatives 557 on co-thermolysis of the sodium salts of benzaldehyde and p-methylbenzaldehyde tosylhydrazones.

In addition to a-allenic a-amino acids, the corresponding allenic derivatives of y-aminobutyric acid (GABA) have also been synthesized as potential inhibitors of the pyridoxal phosphate-dependent enzyme GABA-aminotransferase (Scheme 18.49) [131,138-142]. The synthesis of y-allenyl-GABA (152) and its methylated derivatives was accomplished through Crabbe reaction [131], aza-Cope rearrangement [138] and lactam allenylation [139], whereas the fluoroallene 153 was prepared by SN2 -reduc-tion of a propargylic chloride [141]. 

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