Formaldehyde primary alcohols

Analysis of the Murchison meteorite led to a completely different type of phosphorus compound the only phosphorus-containing compounds found were alkanephos-phonic acids. Spurred on by these results, de Graaf et al. (1995) irradiated mixtures of o-phosphorous acid in the presence of formaldehyde, primary alcohols or acetone with UV light (low pressure Hg lamp, 254 nm with a 185-nm component) and obtained phosphonic acids, including hydroxymethyl and hydroxyethyl phosphonic acids, which had been found in the Murchison meteorite. Alkanephosphonic acids can be derived from phosphorous acid, with a P-H bond being replaced by a P-C bond. 

Acrylamide based acrylics are capable of self crosslinking, when subjected to temperatures in excess of ISiy C. Crosslinking is a complex mixture of condensation reactions and side reactions involving the liberation of water, formaldehyde, primary alcohol and ethers. The reaction is catalysed by acids. Bisphenol A epoxy resins are often incorporated into acrylamide acrylic coating formulations to improve performance. This epoxy resin also takes part in the curing reaction. Figure 4-2 lists the major reactions which take place. 

Note. Formaldehyde is a special case. It reacts similarly, but a primary alcohol is necessarily produced. This alcohol, however, will always contain one carbon atom more than that obtained in Reaction (2). 

Primary alcohols by this analysis are seen to be the products of Grignard addi tion to formaldehyde... 

Hydroxypyrroles. Pyrroles with nitrogen-substituted side chains containing hydroxyl groups are best prepared by the Paal-Knorr cyclization. Pyrroles with hydroxyl groups on carbon side chains can be made by reduction of the appropriate carbonyl compound with hydrides, by Grignard synthesis, or by iasertion of ethylene oxide or formaldehyde. For example, pyrrole plus formaldehyde gives 2-hydroxymethylpyrrole [27472-36-2] (24). The hydroxymethylpyrroles do not act as normal primary alcohols because of resonance stabilization of carbonium ions formed by loss of water. 

The type of alcohol produced depends on the carbonyl compound. Substituents present on the car bonyl group of an aldehyde or ketone stay there—they become substituents on the carbon that bears the hydroxyl group in the product. Thus as shown in Table 14.3 (following page), formaldehyde reacts with Grignard reagents to yield primary alcohols, aldehydes yield secondary alcohols, and ketones yield tertiary alcohols. 

Grignard reagents react with formaldehyde (H2C=0) to give primary alcohols having one more carbon than the Grignard reagent. 

As examples of their addition to carbonyl compounds, Grignard reagents react with formaldehyde, H2C = 0, to give primary alcohols, with aldehydes to give secondary alcohols, and with ketones to give tertiary alcohols. 

Finally, reaction of primary, secondary, or tertiary alcohols 11 with Me3SiCl 14 in the presence of equivalent amounts of DMSO leads via 789 and 790 to the chloro compounds 791 [13]. n-Pentanol, benzyl alcohol, yS-phenylefhanol or tert-butanol are readily converted, after 10 min reaction time, into their chloro compounds, in 89-95% yield, yet cyclohexanol affords after reflux for 4 h cyclohexyl chloride 784 in only 6% yield [13] (Scheme 6.5). 1,4-Butanediol is cyclized to tetrahydrofuran (THF) [13a], whereas other primary alcohols are converted in 90-95% yield into formaldehyde acetals on heating with TCS 14 and DMSO in benzene [13b] (cf also the preparation of formaldehyde di(n-butyl)acetal 1280 in Section 8.2.1). 

Further indirect evidence for the oxidation of the primary alcohol in 5 and the formation of glycoside 6 during the course of the reaction was obtained by electrospray mass spectrometry. Towards this end, excess formaldehyde was added to the reaction mixture after the oxidation of 5 into 6, and the resulting solution stirred for an additional 30 min at ambient temperature to form the instable intermediate 7 (eq 6). The unnatural sugar 5-hydroxymethyl-a-methylglucoside (8) is spontaneously derived from 7 at ambient temperature via a Cannizzarro-like reaction in the presence of excess formaldehyde (eq. 7). 

The addition of Grignard reagents to aldehydes, ketones, and esters is the basis for the synthesis of a wide variety of alcohols, and several examples are given in Scheme 7.3. Primary alcohols can be made from formaldehyde (Entry 1) or, with addition of two carbons, from ethylene oxide (Entry 2). Secondary alcohols are obtained from aldehydes (Entries 3 to 6) or formate esters (Entry 7). Tertiary alcohols can be made from esters (Entries 8 and 9) or ketones (Entry 10). Lactones give diols (Entry 11). Aldehydes can be prepared from trialkyl orthoformate esters (Entries 12 and 13). Ketones can be made from nitriles (Entries 14 and 15), pyridine-2-thiol esters (Entry 16), N-methoxy-A-methyl carboxamides (Entries 17 and 18), or anhydrides (Entry 19). Carboxylic acids are available by reaction with C02 (Entries 20 to 22). Amines can be prepared from imines (Entry 23). Two-step procedures that involve formation and dehydration of alcohols provide routes to certain alkenes (Entries 24 and 25). 

Grignard reagents react with formaldehyde to give (after adding HC1 to the product) primary alcohols. 

As the chain length of the primary alcohols increases, thermal decomposition through fracture of C—C bonds becomes more prevalent. In the pyrolysis of n-butanol, following the rupture of the C3Ht—CH2OH bond, the species found are primarily formaldehyde and small hydrocarbons. However, because of the relative weakness of the C—OH bond at a tertiary site, f-butyl alcohol loses its OH group quite readily. In fact, the reaction... 

It should be noted that, on reaction with Grignard reagents, aldehydes will produce secondary alcohols, whereas ketones will form tertiary alcohols. Often forgotten is the possibility of synthesizing primary alcohols by using formaldehyde as the substrate. 

One way to create a carbon-carbon bond is to react a Grignard reagent with a carbonyl compound. The result of this reaction is an alcohol derived from an aldehyde. Formaldehyde gives a primary alcohol, but any other aldehyde gives a secondary alcohol. Ketones and esters both react to form tertiary alcohols. 

Only formaldehyde yields a primary alcohol by reaction with a Grignard reagent. Figure 14-3 illustrates the reaction of ethylmagnesium bromide with formaldehyde to form 1-propanol. More-complicated alcohols, such as cyclopentylmethanol, can be synthesized by this means (as shown in Figure 144). 

Like Grignard reagents, organolithium compounds react with formaldehyde to produce a primary alcohol. Figure 14-14 illustrates the reaction of an organolithium reagent with formaldehyde. 

The preparation of a primary alcohol from an organo-lithium compound and formaldehyde. 

Addition of organometallic reagent to formaldehyde preparation of primary alcohols... 

Reaction of organometallic compounds with carbonyl compounds a. primary alcohols from methanal (formaldehyde)... 

Methanol is oxidized to formaldehyde and dimethyl formate. Under the experimental conditions, neither formic acid nor its esters were detected. The other primary alcohols are oxidized to give aldehydes and, in a subsequent reaction, carboxylic acids. Acetals and esters are also formed. Profiles of the reaction products in the oxidation of l-propanol are shown in Fig. 19. 

Nucleophilic attack by the vinyl Grignard reagent leads to tertiary alcohol 8 11 Grignuril reagents react with formaldehyde to give primary alcohols and with other aldehydes to give secondary alcohols, whereas ketones are transtormed into tertiary alcohols. 

Experiment 5.39 CYCLOHEXYLMETHANOL (primary alcohol from formaldehyde)... 

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