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Reactions of Diazomethane

CHR) , formed, e g. from the reaction of diazomethane and alcohols or hydroxylamine derivatives in the presence of boron compounds or with metal compounds. Poly-methylene is formally the same as polyethene and the properties of the various polymers depend upon the degree of polymerization and the stereochemistry. [Pg.320]

Heating the adduct of ethylene oxide and sulfur dioxide with primary alcohols in the presence of alkaH hydhdes or a transition-metal haHde yields dialkyl sulfites (107). Another method for the preparation of methyl alkyl sulfites consists of the reaction of diazomethane with alcohoHc solutions of sulfur dioxide (108). [Pg.201]

Thnrane dioxide eplsulfone synthesis by reaction of diazomethane with sulfenes or SOg ... [Pg.360]

Benzyl chloromethyl ketone has been prepared by the reaction of diazomethane with phenylacetyl chloride. The method of Clibbens and Nierenstein, in which one equivalent of diazomethane is added to the acyl chloride and the chloromethyl ketone obtained directly, could not be duplicated by Bradley and Schwarzenbach or by the submitters. [Pg.15]

The regioselectivity of 1,3-dipolar cycloadditions can also be analyzed by MO calculations on transition-state models. For example, there are two possible regioisomers from the reaction of diazomethane and methyl vinyl ether, but only the 3-methoxy isomer is formed. [Pg.648]

In general, reaction of diazomethane with a, -unsaturated carbonyl compounds affords pyrazolines in which the nucleophilic methylene group is attached to the carbon atom of the carbonyl compound. According to Huisgen, the reactions belong to the general class of 1,3-dipolar cycloadditions. [Pg.101]

B-Homosteroids have also been prepared by acid-catalyzed reaction of diazomethane with a,/5-unsaturated ketones. 3/ -Hydroxycholest-5-en-7-one acetate (57) reacts with diazomethane in the presence of concentrated fluoroboric acid, boron trifluoride etherate or aluminum chloride to give 3yS-hydroxy-B-homo-cholest-5-en-7a-one acetate (67). The 7a-keto group is reported to be chemically less reactive than an 11-keto group. [Pg.378]

The high reactivity of monoperfluoroalkyl-substituted alkenes was demonstrated prior to 1972 via the facile reaction of diazomethane with 3,3,3-tnfluoro-propene [9] More recently, such dipolarophiles were found to be similarly reactive... [Pg.799]

Cycloadditions ot diazomethane with fluonnated cyclobutenes provide insight into those factors that govern the reactivity and regioselectivity of such reactions Although 3,3,4,4-tetrafluorocyclobutene undergoes reactions at ambient temperature in 5 min [77, 72], complete reaction with the less reactive perfluorocyclobutene requires 14 days [7J] (equation 8). Note also the regioselectivity observed in the reaction of diazomethane with 3,3-difluorocyclobutene [14] (equation 9)... [Pg.800]

The determination of position of protonation by reaction with diazomethane was performed as follows The enamine was treated at —70° with ethereal hydrogen chloride and the suspension of precipitated salt was treated with diazomethane and allowed to warm slowly to —40°, at which temperature nitrogen was liberated. The reaction with lithium aluminum hydride (LAH) was carried out similarly except that an ether solution of LAH was added in place of diazomethane. The results from reaction of diazomethane and LAH 16) are summarized in Table 1. [Pg.172]

This is illustrated by the reaction of enamine, 113 with sulfene to produce adduct 114 in an 80 % yield (146). The product 114 was also observed in an 18% yield from the reaction of diazomethane, sulfur dioxide, and enamine 113 (153). It was demonstrated that this cyclization reaction must involve sulfene adding to the enamine directly and not acylation of the enamine by... [Pg.238]

The Reactions of Diazomethane with Heterocyclic Compounds Rudolf Gomppeb... [Pg.487]

In this review an attempt is made to discuss all the important interactions of highly reactive divalent carbon derivatives (carbenes, methylenes) and heterocyclic compounds and the accompanying molecular rearrangements. The most widely studied reactions have been those of dihalocarbenes, particularly dichlorocarbene, and the a-ketocarbenes obtained by photolytic or copper-catalyzed decomposition of diazo compounds such as diazoacetic ester or diazoacetone. The reactions of diazomethane with heterocyclic compounds have already been reviewed in this series. ... [Pg.57]

Most reactions of diazomethane with these heterocyclic systems involve attack at other functional groups (for a review see ref. 1), such as in the 0- and iV -methylation of the hydroxy-pyridines and -quino-... [Pg.77]

The reactions of diazomethane with heterocycles containing a ketonic grouping in the ring do not differ, in principle, from those of alicyclic ketones (see footnotes 3 and 177) ring expansion and the formation of epoxides compete. In general, ring expansion is the more important reaction for example, tetrahydropyran-4-one (99) is converted to l-oxacycloheptan-4-one (100) (60%) and 4,4 -epoxy-4-methyltetrahydropyran (101) (23%). ... [Pg.282]

The cycloaddition reaction of diazomethane 4 and an olefin, e.g. methyl acrylate 5, leads to a dihydropyrazole derivative 6 ... [Pg.74]

Reaction of diazomethane with sulphinyl chlorides has been known since 1957. Effective procedures for the synthesis of -halogenosulphoxides 217 based on this reaction were reported by Venier and coworkers . Treatment of alkane or arenesulphinyl chlorides with diazomethane in ether solution gives a-chlorosulphoxides 217a in 70-90% yields. When the same reaction was carried out in the presence of iodide anion it yielded the corresponding iodo derivatives 217b in high yields (equation 123). Bromomethyl trichloromethyl sulphoxide was isolated in 15% yield after treatment of trichloro-methanesulphinyl bromide with diazomethane (equation 124). [Pg.283]


See other pages where Reactions of Diazomethane is mentioned: [Pg.531]    [Pg.174]    [Pg.361]    [Pg.454]    [Pg.194]    [Pg.63]    [Pg.75]    [Pg.245]    [Pg.245]    [Pg.280]    [Pg.283]    [Pg.1374]   


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Diazomethane, reactions

Ethers by reaction of diazomethane with alcohols

Heterocyclic compounds reactions of diazomethane with

Other Reactions of Diazomethane with Heterocycles

Reactions of diazomethane with

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