Aldehydes 2-chloro, vinylic

An earlier investigation (23) demonstrated that the Vilsmeier-Haack reaction of the ArCOCHj type compounds gives the monoformylated compounds or the corresponding P-chloro-vinyl aldehydes. It was found, however, that in the case of o-hydroxyacetophenones, the methyl group was doubly formyl-ated by a Vilsmeier reagent to give our first target compounds, 4-oxo-4H-l-benzopyran-3-carboxaldehydes ( ) in one step ( 1, J ). The reason why double formylation took... 

A comprehensive article related to the formation of aryl-l-(chloro-thio)formimidoyl chlorides XLI appeared recently and the reaction of XLI with a variety of amines has been reported ( ). The enormous reactivity of XLI was further evidenced by the formation of 1 1 adducts with aldehydes and vinyl ethers ( ). For example, reaction of XLI (R = C Hs) with vinylethyl ether yields 3-phenyl-1,3-thiazolin-2-one (XLII) ( ). 

The imide nitrogen atom was also most reactive to a variety of electrophilic species (hydrogen halides, pseudohalogens, and alkyl halides) in the parent Rimidophosphazenes, R(C—NH)-N=PPh3. With t-butyl hypochlorite the /V-chloro-derivatives, R(C=NCl)-N=PPh3, were obtained. R/ -Vinyl-phenylphosphazenes have been prepared by condensation of aldehydes with active methylene compounds ... 

In a similar approach, Duhamel et al. [60] studied the catalyzed condensation (BF3-Et20 or ZnCh) of vinyl-(3-ionol with a chloro-enolether. The intermediary aldehyde (all E19Z 65/35) had been... 

Vinylic chlorine is replaced by hydrogen in l-chloro-3,4-dihydro-2-naphthaldehyde during catalytic hydrogenation, which saturates the double bond, but leaves the aldehyde group intact (equation 9). ... 

Epoxides. Allylstannanes react under the influence of Pbl -HMPA with carbonyl compounds such as a,P-epoxy ketones and a-bromoketones give epoxy products. On the other hand, the reaction of l-chloro-3-tributylstannyl-l-propene with aldehydes leads to vinyl-epoxides. 

Vinyl chloroformates with the general formula R R"C=CH0C(0)C1 (R = R" = Me R = Me, R" = Cl R = Me, R" = Pr) have been prepared by the addition of phosgene to an aldehyde group adjacent to a 1-chloro atom, followed by removal of chlorine in situ, using zinc dust [242c] ... 

Cyclopropylamines react with aldehydes to yield the corresponding imines in fair yield.Cyclopropane-1,2-diamine reacted with two equivalents of benzaldehyde to give corresponding diimine 1 in 58% yield. Imine formation is also involved as the key step in multistep reactions leading to a variety of complex compounds. For example, 4-[2,2-bis(benzyloxymethyl)cyclopropylamino]-6-chloro-5-formamidopyrimidine (2) reacted with triethyl orthoformate in the presence of hydrochloric acid to give purine derivative 3 in 58% yield. An analogous reaction took place when 1-azido-l-vinylcyclopropane was treated successively with triphenylphosphane and benzaldehyde to give iV-benzylidene-l-vinyl-cyclopropylamine in almost quantitative yield. 

Various functionalized allylic halides have been used under the Luche conditions. Thus, 2-bromomethyl acrylate reacted with carbonyl compounds to give a-methylene-y-butyrolactones after acidic treatment of the alcoholic intermediate [102]. The reaction of ciimamyl chloride with aldehyde, unlike cinnamyl bromide which led to phenyl propene leaving the aldehyde unchanged [103], gave the diastereoisomeric y-products whereas the reaction with ketones gave mixtures of a- and y-products [104]. In the presence of zinc dust, l-chloro-3-iodopropene yielded the corresponding chlorohydrin when reacted with aldehydes or ketones under aqueous conditions. In this way, further treatment with base gave vinyl oxiranes whereas zinc in the presence of aqueous HBr led to (E)-buta-1,3-dienes (Scheme 21) [1051. 

Other synthons for 1,3-dicarbonyl compounds that have been successfully applied include p-chloro-a,P-unsaturated ketones and aldehydes, P-dimethylamino-a,P-unsaturated ketones (easily obtained from ketones by reaction with DMFDMA), P-alkoxy-enones"" and vinyl-amidinium salts."" Alkynyl-ketones react with 5-alkyl-isothioureas, giving 2-alkylthio-pyrimidines" and propiolic acid reacts with urea to give uracil directly in about 50% yield. "" 1,3-Keto-esters with formamidine produce 4-pyrimidinones"" and C-substituted formamidines with ethyl cyanoacetate give 2-substituted-6-amino -pyrimidinones. In analogy, pyrimidines fused to other rings, for example as in quinazolines, can be made from ortho-aminonitriles " and in general, from P-enamino esters. ... 

Treatment of enolizable aldehydes with 2-chloro-3-ethylbenzoxazolium tetrafluoroborate, tri-ethylamine and tetraethylammonium chloride affords vinyl chlorides57. The yields and EjZ ratios of the products in this reaction are given in Table 2. 2-Octanol and other secondary alcohols are chlorinated with inversion of configuration under similar conditions58-61. 

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