Alkylation process
AssigneeCanadian Patents and Development Limited
InventorsBasil V. Gregorovich, Stewart F. MacDonald
Life of this patent
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Abstract
Substituted pyrrole compounds, such as 3-ethyl-4-methyl-5-carbethoxy pyrrole, 2,4-dimethyl-3-acetyl pyrrole and 2-methyl-5-carboxy pyrrole-4-propionic acid diethyl ester, are alkylated in a single step by reaction with an aldehyde or ketone in the presence of both an acid condensing agent such as hydriodic acid and a compatible reducing agent such as metallic zinc or stannous chloride. Suitable carbonyl reactants include formaldehyde, paraldehyde, isobutyraldehyde, acetone, cyclohexanone and methyl-isobutyl ketone. This application is a continuation application of U.S. application Ser. No. 281,624 filed Aug. 18, 1972, now abandoned, which is a continuation-in-part application of U.S. application Ser. No. 832,001, filed June 10, 1969, now abandoned.
Claims7
A single step method of ring alkylating a substituted pyrrole compound which comprises the steps of
- reacting in a liquid system (1) a substituted pyrrole compound selected from the group consisting of 2,4-dimethyl-5-carbethoxy pyrrole, 2,4-dimethyl-3,5-dicarbethoxy pyrrole, 2-methyl-3-carbethoxy pyrrole, 2,4-dimethyl-3-acetyl pyrrole, 2-carbethoxy-3-methyl-pyrrole, 2-methyl-5-carbethoxy pyrrole, 2,3-dimethyl-5-carbethoxy pyrrole, 2,4-dimethyl-3-bromo-5-carbethoxy pyrrole, 3-ethyl-4-methyl-5-carbethoxy pyrrole, 3-methyl-4-carbethoxy pyrrole, 2,5-dimethyl-3-carbethoxy pyrrole, 2-methyl-3,5-dicarbethoxy pyrrole, 3-methyl-2,5-dicarbethoxy pyrrole, 2,3-dimethyl-5-carbethoxy pyrrole, 2,3-dimethyl pyrrole, 2,5-dimethyl pyrrole, 2-methyl-5-carboxy pyrrole-4-propionic acid diethyl ester and 2,4-dimethyl pyrrole;
- with (2) a carbonyl compound selected from the group consisting of formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, paraldehyde, heptaldehyde, laurylaldehyde, stearaldehyde, amino-acetaldehyde, acetone, diethyl-ketone, isobutyl-methyl ketone, 3-pentanone, cyclopentanone, cyclohexanone, pyruvic acid, levulinic acid, glyoxylic acid, benzaldehyde acetophenone, chloroacetone, 2,5-hexane dione and 2-formyl-3-acetyl-4-methyl-5-carbethoxy-pyrrole
- in the presence of both (a) an acid condensing agent selected from the group consisting of hydriodic acid, aqueous HI, HI in acetic acid, HI in heptane, HBr in acetic acid HCl in acetic acid, H.sub.2 SO.sub.4 in acetic acid, hydrobromic acid, sulfuric acid, and hydrochloric acid;
- and (b) a reducing agent selected from the group consisting of hydrogen iodide, zinc, zinc in acid, zinc amalgam, stannous bromide, and stannous chloride and when said reducing agent is hydrogen iodide, there may be included also an auxiliary substance selected from the group consisting of red phosphorus, phosphonium iodide, and hypo-phosphorous acid
- at a temperature sufficient to effect reaction between the substituted pyrrole compound (1) and said carbonyl compound (2)
- whereby to form from the reactants a derivative of said pyrrole compound in which the carbon of said carbonyl group is attached to the pyrrole ring.
A single step method of ring alkylating a substituted pyrrole compound which comprises the steps of
- reacting in a liquid system (1) a substituted pyrrole compound selected from the group consisting of 2,4-dimethyl-5-carbethoxy pyrrole, 2,4-dimethyl-3,5-dicarbethoxy pyrrole, 2-methyl-3 carbethoxy pyrrole, 2,4-dimethyl-3-acetyl pyrrole, 2-carbethoxy-3-methyl-pyrrole, 2-methyl-5-carbethoxy pyrrole, 2, 3-dimethyl-5-carbethoxy pyrrole, 2,4-dimethyl-3-bromo-5-carbethoxy pyrrole, 3-ethyl-4-methyl-5-carbethoxy pyrrole, 3-methyl-4-carbethoxy pyrrole, 2,5-dimethyl-3-carbethoxy pyrrole, 2-methyl-3,5-dicarbethoxy pyrrole, 3-methyl-2,5-dicarbethoxy pyrrole, 2,3-dimethyl-5-carbethoxy pyrrole, 2,3-dimethyl pyrrole, 2,5-dimethyl pyrrole, 2-methyl-5-carboxy pyrrole-4-propionic acid diethyl ester and 2,4-dimethyl pyrrole with (2) a carbonyl compound generated in situ from paraformaldehyde or paraldehyde
- in the presence of both (a) an acid condensing agent selected from the group consisting of hydriodic acid, aqueous HI, HI in acetic acid, HI in heptane, HBr in acetic acid HCl in acetic acid, H.sub.2 SO.sub.4 in acetic acid, hydrobromic acid, sulfuric acid, and hydrochloric acid;
- and (b) a reducing agent selected from the group consisting of hydrogen iodide, zinc, zinc in acid, zinc amalgam, stannous bromide, and stannous chloride and when said reducing agent is hydrogen iodide, there may be included also an auxiliary substance selected from the group consisting of red phosphorus, phosphonium iodide, and hypo-phosphorous acid
- at a temperature sufficient to effect reaction between the substituted pyrrole compound (1) and said carbonyl compound (2)
- whereby to form from the reactants a derivative of said pyrrole compound in which the carbon of said carbonyl group is attached to the pyrrole ring.
Dependencies are inferred from the claim text.