METHYL BENZOYLAMINO-2-HYDROXYACETATES

Abstract: Compounds of the general formula (VI) : wherein R¹ is : (a) a phenyl group optionally substituted by one or more halogen atoms, cyano groups, C 1-6 alkoxy groups, methylene- or ethylenedioxy groups, C 1-6 alkyl groups or C 1-6 haloalkyl groups (eg. trifluoromethyl groups); or (b) a furyl, thienyl or pyridyl group optionally substituted by one or more C 1-6 alkyl groups, C 1-6 haloalkyl groups or halogen atoms, but excluding methyl-(3-­ methoxybenzoylamino (hydroxyl)) acetate. The compounds are useful as intermediates in the preparation of fungicides.

Description: This invention relates to methyl benzoylamino-2-­ hydroxyacetates and to their preparation. According to the invention there are provided compounds of the general formula (VI): wherein R¹ is: (a) a phenyl group optionally substituted by one or more halogen atoms, cyano groups, C 1-6 alkoxy groups, methylene - or ethylenedioxy groups, C 1-6 alkyl groups or C 1-6 haloalkyl groups (eg. trifluoromethyl groups); or (b) a furyl, thienyl or pyridyl group optionally substituted by one or more C 1-6 alkyl groups, C 1-6 haloalkyl groups or halogen atoms, but excluding methyl-(3-­ methoxybenzoylamino (hydroxyl)) acetate. In the foregoing definition, the term "halogen" is intended to include fluorine, chlorine, bromine and iodine. Particular examples of the terms alkyl, alkoxy and haloalkyl are methyl, ethyl, propyl, isopropyl, methoxy, ethoxy and trifluoromethyl. The compounds of the invention are useful as intermediates in the preparation of the amide described and claimed in our European Patent Application 0076030. The present invention is concerned particularly with compounds in which R¹ is phenyl optionally substituted at one or more of the 3-, 4- or 5-positions with one or more halogens or C 1-6 alkyl, C 1-6 alkoxy, trifluoromethyl or methylene or ethylene-dioxy groups. Thus, R¹ can be, for instance, phenyl substituted at the either 3- or 4-position, or both, with chlorine, fluorine, bromine, methyl, methoxy or methylenedioxy (3,4-­ only). Examples of suitable values for R¹ are : 3,4-OCH₂O.C₆H₃, 4-Cl.C₆H₄, 4-CH₃.C₆H₄, 4-Br.C₆H₄, 4-CH₃O.C₆H₄, 3-F,4-CH₃.C₆H₃ or 4-Cl-3,F-C₆H₃. Particular examples of values for R¹ of compounds of the invention are listed below in Table I. In the foregoing Table Compound Nos 67, 72, 73, 76, 78, 81 and 84 are of particular interest because they are intermediates for especially useful fungicidal compounds of European Application 0076030. The structural formula given above is believed to be the one which best represents the structure of the compounds of the invention. For some compounds within the scope of the formula (VI) it may be possible in principle for tautomeric forms of the compounds to exist, in which a hydrogen atom is transposed from the position in which it is shown in formula (VI) to another part of the molecule, and the chemical bonds between the atoms of the molecule are consequently rearranged. The structural formula (VI) is intended to represent and include such tautomeric forms, insofar as they may exist. It will be noted that the formula (VI) includes an asymmetric carbon atom (the one to which the hydroxyl group depicted is attached) and the molecule is therefore capable in principle of existing in two optically isomeric forms (D and L forms). The present invention includes the separate D and L forms of the compounds as well as mixtures of the D and L forms in all proportions. As normally prepared by chemical synthesis the compounds are obtained as mixtures of equal proportions of the D and L forms (ie. racemic mixtures). Methods of separating racemic mixtures into the D and L forms are well known in the art. The structural formula (VI) is also intended to include any physically distinguishable modifications of the compounds which may arise, for example, from different ways in which the molecules are arranged in a crystal lattice, or from the inability of parts of the molecules to rotate freely in relation to other parts, or from geometrical isomerism, or from intra-molecular or inter-molecular hydrogen bonding, or otherwise. The invention further provides a process for preparing compounds of formula (VI) above, which comprises bringing into reaction an amide of the formula R¹CONH₂, where R¹ is as defined above, with methyl glyoxylate. This process can be represented as follows : Scheme This process is conveniently carried out in a solvent and may be accelerated by heating. Examples of solvents include liquid hydrocarbons, for example toluene and the xylenes. The reaction may be carried out at temperatures in the range from 50°C to 120°C and preferably above 100°C. The hydroxy acetate product (VI) may be isolated by removal of the solvent. The hydroxy acetate (VI) can be converted into compounds of general formulae (VIII) and (IV) as follows with reference to the following scheme : Thus, the hydroxy acetate can be converted to the unstable chloro- compound (VII) by treatment with thionyl chloride. Conveniently the reaction is carried out in an excess of thionyl chloride as solvent. The reaction proceeds at moderate temperatures (for example, temperatures in the range from 15°C-50°C). The chloro compound (VII) may be isolated by removal of the excess of thionyl chloride under reduced pressure. The chloro compound (VII) is then reacted with a 5-membered heteroaromatic compound XH (where X is 1-pyrazolyl, 1-­ (1,2,4-triazolyl) or 1-tetrazolyl, each optionally substituted by one or more C 1-6 alkyl groups) in the presence of an acid acceptor. Examples of acid acceptors include tertiary amines, for example triethylamine, pyridine, and dimethylaniline. Conveniently the reaction may be performed using an excess of pyridine as both solvent and acid acceptor. The reaction proceeds at moderate temperatures (ie. temperatures in the range 15°C - 10°C). The ester product (VIII) from the foregoing reaction is then reacted with ammonia to give the amide intermediate (IV); the reaction with ammonia is conveniently carried out in a solvent, for example a lower alkanol (eg. methanol or ethanol) or an ether (eg. diethyl ether or tetrahydrofuran). The reaction may be carried out by saturating the solution of the ester (VIII) with ammonia at a lowered temperature (eg. -50°C to -10°C) and subsequently allowing the mixture to warm to room temperature. The amide (IV) so obtaine may then be converted if desired to the corresponding nitrile b dehydration, for instance by treatment of a solution of (IV) in pyridine with trifluoroacetic anhdyride. This reaction is generally exothermic and is preferably carried out below 0°C, for example at a temperature in the range from -20°C to -10°C. The nitrile thus obtained may be isolated from the reaction mixture by conventional methods. The process of the invention is illustrated by the following Example. EXAMPLE Methyl 2-(3,5-dimethylbenzoylamino)-2-hydroxy acetate was prepared by refluxing equimolar proportions of 3,5-­ dimethylbenzamide and methyl glyoxylate in toluene and then removing the solvent under reduced pressure. The hydroxy acetate was obtained in a yield of 3 grams.

Claims: 1. Compounds of the general formula (VI) : wherein R¹ is: (a) a phenyl group optionally substituted by one or more halogen atoms, cyano groups, C1-6 alkoxy group, methylene- or ethylenedioxy groups, C1-6 alkyl groups or C1-6 haloalkyl groups (eg. trifluoromethyl groups); or (b) a furyl, thienyl or pyridyl group optionally substituted by one or more C1-6 alkyl groups, C1-6 haloalkyl groups or halogen atoms, but excluding methyl-(3-methoxybenzoylamino(hydroxy)) acetate. 2. Compounds according to claim 1, wherein R¹ is phenyl optionally substituted at one or more of the 3-, 4- or 5-positions with one or more halogens or C1-6 alkyl, C1-6 alkoxy, trifluoromethyl or methylene- or ethylene­ dioxy groups. 3. Compounds according to claim 1 or claim 2, wherein R¹ is phenyl substituted at the either 3- or 4-position, or both, with chlorine, fluorine, bromine, methyl, methoxy or methylenedioxy (3,4-only). 4. A compound of the formula (VI) wherein : R¹ is 3,4-OCH₂O.C₆H₃, 4-Cl.C₆H₄, 4-CH₃.C₆H₄, 4-Br.C₆H₄, 4-CH₃O.C₆H₄, 3-F,4-CH₃.C₆H₃ or 4-Cl-3,F-C₆H₃. 5. A compound as defined in any of the preceding claims, which is in the form of a stereoisomer. 6. A process for preparing a compound claimed in claim 1, which comprises bringing into reaction an amide of the formula R¹CONH₂ where R¹ is as defined in claim 1 with methyl glyoxylate. 7. A process according to claim 6, carried out in a liquid hydrocarbon solvent and at a temperature in the range of 50° to 120°C. 8. A process according to claim 7, in which the solvent is selected from toluene and xylenes. 9. A process according to claim 8, carried out at a temperature above 100°C.

Inventors: KAY, IAN TREVOR, NOON, ROBERT ANDREW
Applicants: IMPERIAL CHEMICAL INDUSTRIES PLC
Application year: 1982
Main classification: C07C103
IPC codes: A01N43, C07D409, C07D231, C07D521, C07D405, C07D249, C07D257