With ROH

Alkylation of 2-methylaminothiazole (204) with ROH in 85% sulfuric acid gives 2-methylimino-3-alkyl-4-thiazoIine (54). 2-Amino-4-rnethyl-thiazoie alkylated with an excess of isopropanol, however, gives 95% of 2-isopropylamino-4-methyl-5-isopropylthiazole (56). The same result is obtained with cyclohexanol (242). These results and those reported in Sections III.l.C and IV.l.E offer interesting new synthetic possibilities in thiazole chemistry. The reactive species in these alkylations is the conjugate acid of 2-aminothiazole. and the diversity of the products obtained suggests that three nucleophilic centers may be operative in this species. 

Because each carboxyl group reacts at a different rate with alcohol, a mixed diester or triester can be prepared if the reactions of the acid with ROH and R OH are carried out sequentially. 

Chandler [Bull. Br Coal Util. Re.s. A.s.soc., 29(10), 333 (11), 371 (1965)] finds no good correlation of grindabihty measured on 11 coals with roh crushing and attrition, and so these methods should be used with caution. The Bond grindability method is described in the subsection Capacity and Power Consumption. ... 

Figure 4. Scheme showing the reaction of trimethylchlorosilane with ROH, where R may be either H or a polymeric moiety... 

This also explains the use of pyridine in acetic anhydride as an acetylating reagent6 in the determination of primary or secondary alcohols and amines according to the following sequential reactions (with ROH as an example) ... 

Carbonyl compounds react with thiols, RSH, to form hemi-thioacetals and thioacetals, rather more readily than with ROH this reflects the greater nucleophilicity of sulphur compared with similarly situated oxygen. Thioacetals offer, with acetals, differential protection for the C=0 group as they are relatively stable to dilute acid they may, however, be decomposed readily by H20/HgCl2/CdC03. It is possible, using a thioacetal, to reverse the polarity of the carbonyl carbon atom in an aldehyde thereby converting this initially electrophilic centre into a nucleophilic one in the anion (31) ... 

Thus acid chlorides and anhydrides react readily with ROH and NH3 to yield esters and amides, respectively, while esters react with NH3 or amines to give amides, but the simple reversal of any of these reactions on an amide, though not impossible, is usually pretty difficult. The relative reactivity will also depend on both the electronic and, more particularly, the steric effect of R. A slightly unusual leaving group is eCX3 (e.g. eCI3) in the haloform (158) reaction (cf. p. 297) ... 

Table 1. Rate constants k and equilibrium constants K for the acid-catalyzed cleavages of (XMe2Si)20 with ROH...

Alkoxy-3-(4-biphenyl)perhydropyrido[l,2-z1[l,4]oxazines were obtained from the 3-hydroxy derivative with ROH and Br(CH2)3OH in a boiling acidified medium <2000JME609, 2000WO00/042030, 2002JME5406>. The piperidin-... 

Figure 5. Rate constants (logJfcq) for quenching of dimethoxycarbene (197) with ROH (Table 3)" as a function of pAfa (ROH).156 A theoretical Eigen curve (solid line) was fitted to the data points (circles). The dotted lines are extrapolated from the portions of the Eigen curve where a = 0 and a = —1. These dotted lines cross at pKa (ROH) = pKa [(MeO C ].155...

Section 6.1.2) second, RS is a better leaving group than RO (see Section 6.1.4), again because of size and the less localized electrons. Simple nucleophilic reactions with H2S parallel those with H2O, and those with RSH parallel those with ROH. This gives rise to carboxylic acid derivatives containing sulfur, such as thioacids and thioesters. 

The effect of alkyl alcohol on the surface adsorption and micellization of FC surfactant is noticeably different from HC surfactant. The molecular interactions between ROH and C7pNa in the surface layer are shown to be weaker (Smaler l jl-value) as compared with ROH-C, SNa system. 

In acid solution it is assumed that the aquapenta-cyano ion reacts to form an intermediate, and that the intermediate may react with water, or may be picked up by a scavenger such as azide ion to form products. It is also assumed that the complex, which has a pK of 9.8 is in equilibrium with ROH, the predominant species in akaline solution. The decision that we had to make was whether the decrease in rate occurred because ROH was a completely inert species, or whether ROH also underwent an Svl mechanism as well as this. It was our conclusion that the evidence favored two parallel Sn mechanisms. 

Some well-defined scandium alkoxides have been synthesized and studied (together with lanthanide analogues). The compounds are [Sc(OR)3], Sc(OR)3(THF), Sc(OR)3(tppo) and (RO)2Sc(u-OR)2Na(THF), where R = 2,6-di-t-butyl-4-methylphenate. [Sc(OR)3] was prepared by reaction of Sc N(SiMe3)2 3 with ROH in hexane at 20°C followed by reflux, or by reaction of NaOR and ScCl3 in boiling THF, or by sublimation of Sc(OR)3(THF). The latter and... 

The insertion of carbon dioxide into a transition metal-oxygen bond, e.g., a metal alkoxide, results in an organic carbonate ester, coordinated in either a monodentate or bidentate manner. Only a limited number of such reactions have been observed, and little mechanistic information is available. The reactions may proceed by interaction of C02 with ROH or RO in solution followed by metal coordination, in a manner similar to the C02 reactions with the early transition metal dialkylamides. Alternatively, direct attack of C02 on the alkoxide oxygen might occur, or a C02 adduct may form as an intermediate. 

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