Abstract: One aspect of the present invention relates to novel reaction conditions that allow the efficient synthesis of diaryl ethers from arenes bearing a leaving group and arenols under relatively mild conditions. Another aspect of the present invention relates to the dramatic effects of acidic activators on Ullmann-type couplings involving electron-poor and/or relatively insoluble substrates.

Abstract: A process for preparing ketones by so-called “crossed aldol condensation” of a ketone with an aldehyde in the presence of a catalyst system consisting of approximately equimolar amounts of a secondary amine and of a carboxylic acid containing at least 2 C atoms, to form an &agr;,&bgr;-unsaturated ketone, and, where appropriate, subsequent catalytic hydrogenation. The process is used in particular for preparing 6-methyl-3-hepten-2-one by reacting acetone with isovaleraldehyde, and for preparing its hydrogenation product, 6-methylheptan-2-one, which is an important precursor for numerous active substances, in particular for preparing lipid-soluble vitamins such as vitamin E.

Abstract: A process for preparing a compound of the formula I where R1 and R2 are hydrogen or C1-C4-alkyl and R3 is C1-C10-alkyl, phenyl or C1-C4-alkyl-substituted phenyl, comprises reacting a compound II with a compound of the formula III where X is chlorine, bromine or iodine, in the presence of a Friedel-Crafts catalyst in one step to give a compound I.

Abstract: The present invention relates to compounds selected from formula I wherein R1, R2, R3 and R4 are the same or different and represent hydrogen, C1, to C6-alkyl, C5 to C6-cycloalkyl, phenyl and halogen, m and n are the same or different and represent the 2, 3, 4 or 5, X, A and B represent carbon and Y1, Y2, Z1 and Z2 are the same or different and represent hydrogen, hydroxyl (OH), amino (NH2), isocyanato (NCO) or 4-hydroxyphenyl.

Abstract: Compounds of formula I, ##STR1## and the physiologically tolerable salts thereof, wherein the substituents R.sub.1 -R.sub.4 have the meanings given in the specifications and show an activity against inflammatory conditions.

Abstract: A process of preparing the compound of formula (I) which comprises: (a) reacting butyryl chloride with the compound of formula (IV) in the presence of a Friedel-Crafts catalyst in an inert diluent to produce a compound of formula (II) and (b) reacting the compound of formula (II) with ethoxyamine. Compound (II) is also claimed.

Abstract: The condensation reaction of a ketone with either an ester or a carbonate to form, respectively, a 1,3-diketone or a .beta.-ketoester often affords poor results under the standard condensation reaction conditions. High yields and high purities of the desired product can be obtained by performing the reaction using an alkoxide base in DMSO as the sole solvent.

Abstract: An improved process is described for preparing .gamma.,.delta.-unsaturated ke-tones, which are in demand as aroma substances and intermediates for vitamins and carotenoids, by reacting tertiary allyl alcohols and alkenyl alkyl ethers in the presence of acid catalysts at elevated temperature, which comprises carrying out the reaction in the presence of a phosphorus derivative of the formula IV ##STR1## where A and B are each a branched or unbranched alkyl or alkoxy having from 1 to 10 carbons, a substituted or unsubstituted aryl, cycloalkyl, aryloxy or cycloaryloxy;A can additionally be --H or --OH orA and B together are a substituted or unsubstituted tetramethylene or pentamethylene or substituted or unsubstituted phenyl-1,2-diol or 1,1'-binaphthyl-2,2'-diol.

Abstract: A process for making a phenolic ketone involving reacting a metal aryloxide with an aliphatic aldehyde having from at least 2 to about 25 carbon atoms.

Abstract: A process for making a sterically-hindered beta-diketone involving: (a) providing a solution comprising: (i) an ester; (ii) a base; and (iii) a solvent; (b) adding a ketone selected from the group consisting of an aromatic ketone and a hindered aliphatic ketone, to the solution, to form a condensation reaction mixture, whereby either the ester or the ketone is hindered; (c) reacting the solution with the ketone to form a sterically-hindered beta-diketone; and (d) recovering the sterically-hindered beta-diketone from the condensation reaction mixture.

Abstract: A process is described for the synthesis of 2-hydroxy-4-alkyloxy benzophenone by the selective alkylation of 2,4-dihydroxy benzophenone with a dialkyl carbonate, in liquid phase, in the presence of suitable catalysts, at a temperature ranging between 120.degree. and 220.degree. C. and at a total pressure ranging from 2 to 60 ate.

Abstract: A process for alkoxylating phenols is disclosed. The process comprises reacting a carbonyl-functionalized phenol with an alkylene oxide in the presence of a substantially non-crystalline double metal cyanide (DMC) catalyst. The process offers fast reaction times at low catalyst levels, reduced problems with condensation side reactions, and low-color, low-viscosity, low-polydispersity alkoxylated phenols. The process enables efficient preparation of alkoxylated carbonyl-functonalized phenols that are especially valuable in the surfactant industry.

Abstract: New process for the synthesis of the antiinflammatory drug known as nabumetone that consists in reacting 2-acetyl-5-bromo-6-methoxynaphthalene with an alkyl acetate in presence of an alkaline alcoholate to get 4-(5-bromo-6-methoxy-2-naphthyl)-4-hydroxybut-3-en-2-one that by catalytic hydrogenation in a polar solvent and in presence of a base gives 4-(6-methoxy-2-naphthyl)butan-2-one known as nabumetone.

Abstract: Hydroxylated benzophenonens are prepared from completely or partially methylated hydroxybenzophenones by reacting these methyl ethers with AlCl.sub.3 and subsequently hydrolyzing with water, the reaction being carried out in the presence of one or more compounds from the class of ureas or carboxamides.

Abstract: Benzocyclobutene-terminated monomers of the formula ##STR1## wherein Ar is --SO.sub.2 --, --CO--, or ##STR2## are prepared by reacting a benzocyclobutene of the formula ##STR3## wherein R is --H or --SiMe.sub.3, with a difluorophenyl compound of the formula ##STR4## wherein Ar is as described previously, in the presence of a promoter. A mixture of the resins is obtained when potassium carbonate is employed as the promoter. The bis(benzocyclobutene)-terminated monomer is obtained when cesium fluoride is employed as the promoter.

Abstract: A particularly advantageous process for the preparation of 2,2-dialkyl-arylidene-cycloalkanones is characterized in that 2-alkyl-arylidene-cycloalkanones are reacted with alkyl halides in the presence of metal hydroxides and tertiary alcohols.

Abstract: Ketones having at least one hydrogen atom or ester group in the .alpha.-position with respect to a ketonic carbonyl group thereof, for example cyclopentanone, 2-methylcyclopentanone and other substituted cyclopentanones, are effectively C- or .alpha.-alkylated, especially on an industrial scale, by reacting same with an alkylating agent in the presence of a catalytically effective amount of a condensed or uncondensed orthophosphate anion.

Abstract: The present invention relates to novel 4-halo-2-fluoro-5-alkoxybenzoyl compounds and their methods of manufacture. These compounds are useful for the preparation of agricultural chemicals and medicines, particularly as intermediates for an active class of arylhaloalkylpyrazole and aryl alkylsulfonylpyrazole herbicides.

Abstract: The palladium-catalyzed coupling of aryl and vinyl halides with vinylic compounds is disclosed. A preferred embodiment relating to the palladium catalyzed coupling of 4-substituted and 6-substituted-2-methoxynaphthalene to form nabumetone is also disclosed. The beauty of this novel reaction is that methylvinylketone, normally employed by the art directly as-is for the preparation of nabumetone, is formed in situ. We have discovered a mechanism to take advantage of the in situ formation of methylvinylketone, thus avoiding the use of expensive, toxic, and unstable methyl vinyl ketone feed. This reaction may be employed for a variety of pharmaceutically active and non-pharmaceutical compounds.

Abstract: The compounds of formula ##STR1## wherein symbol X represents a --CHO group or an acetal group of formula ##STR2## symbols R', taken separately, represent each a C.sub.1 to C.sub.4, linear or branched, saturated or unsaturated, hydrocarbon radical or, taken together, represent a C.sub.1 to C.sub.4 alkylene radical, which may be substituted, and symbol R represents a hydrogen atom or a methyl radical, are useful as perfuming ingredients for the preparation of perfuming compositions and perfumed articles, to which they impart floral type notes.

Abstract: The present invention provides special epoxy derivative (1), cyclohexanone derivative (2), cyclohexenone derivative (3) and 3-substituted cyclohexenone derivative (4) which are useful as intermediates for synthesizing physiologically active materials, and a method for stereoselectively introducing substituted groups. Further, the present invention provides a method for synthesizing optically active compounds, such as optically active carvone via these intermediates.

Abstract: Arylketoamines are prepared by reacting arylisonitrosoalkanones with hydrogen in the presence of a transition metal catalyst and a liquid carboxylic acid at a temperature of less than about 600.degree. C.

Abstract: The present invention provides special epoxy derivative (1), cyclohexanone derivative (2), cyclohexenone derivative (3) and 3-substituted cyclohexenone derivative (4) which are useful as intermediates for synthesizing physiologically active materials, and a method for stereoselectively introducing substituted groups. Further, the present invention provides a method for synthesizing optically active compounds, such as optically active carvone via these intermediates.

Abstract: A process for producing an optically active .beta.-hydroxyketone represented by formula (I): ##STR1## by catalytic asymmetrical aldol reaction is disclosed, comprising reacting a silyl-enol ether represented by formula (II): ##STR2## with a substituted aldehyde represented by formula (III):R.sup.5 CHO (III)in the presence of a binaphthol-titanium complex represented by formula (IV): ##STR3## An optically active .beta.-hydroxyketone is efficiently produced with diastereo-specificity and enantio-specificity.

Abstract: A process for preparing 4-alkanoylaryl benzyl ethers of the general formula I ##STR1## where R is hydrogen, halogen, cyano; alkyl, alkoxy;X is CH.sub.2, CH--CH.sub.3, CH--CH.sub.2 --CH.sub.3, CH--OCH.sub.3 or N--OCH.sub.3 ;Y is oxygen, sulfur, direct linkage or nitrogen;m is 0, 1, 2 or 3;R.sup.1 is hydrogen; alkyl, alkenyl, alkynyl or alkoxy;R.sup.2 is cyano, halogen, alkyl, alkoxy or haloalkyl;R.sup.3 is alkyl; haloalkyl; cycloalkyl; or an unsubstituted or substituted mono- to trinuclear aromatic system,comprises reacting an aryl benzyl ether of the general formula II ##STR2## where X, Y, R, R.sup.1, R.sup.2 and m have the abovementioned meanings, with a carbonyl halide or with a carboxylic anhydride or with a carboxylic sulfonic anhydride in the presence of an acid and in the presence or absence of a diluent.

Abstract: A process for preparing an hydroxyketone of the formula (X): ##STR1## wherein Ar represents substituted phenyl, aromatic heterocyclic, or substituted aromatic heterocyclic; R.sup.1 and R.sup.2 independently represents hydrogen, C-1 to C-16 alkyl, aromatic, substituted aromatic, aromatic heterocyclic, substituted aromatic heterocyclic or C-1 to C-5 alkyl covalently bonded to Ar, with the provision that R.sup.1 and R.sup.2 are different. The process comprises contacting a compound of the formula (V): ##STR2## with a solvent, a base and a chiral hydroxylating agent at a temperature of about -85.degree. C. or less.Compounds of the formulae ##STR3## also are disclosed.

Abstract: The invention relates to a method of preparing a compound having an alkyl or alkoxyalkyl side-chain with a terminal 2-hydroxyprop-2-yl group, by oxidizing a compound having a terminal isopropyl group in its side-chain with a dioxirane as the oxidant.

Abstract: Disclosed herein is a process for producing a .gamma.-hydroxyketone (2), which comprises asymmetrically hydrogenating a .gamma.-diketone (1) in the presence of a ruthenium-optically active phosphine complex as a catalyst ##STR1## wherein R.sup.1 and R.sup.2 mean individually an alkyl or phenyl group which may have a substituent group. According to the invention, optically active .gamma.-hydroxyketones useful in synthesizing optically active moiety in, biodegradable polymers, perfumes, intermediates for synthesizing medicines and the like can be efficiently prepared.

Abstract: Di-amines endowed with chain extension activity for formulations such as polyureas and polyurethanes are disclosed, and which have the general formula: ##STR1## wherein n is 0-1000; R.sub.1, R.sub.2, R.sub.5, and R.sub.6 are each independently selected from the group consisting of H, --CH.sub.3, --CH.sub.2 CH.sub.3, --CH.sub.2 OH, and --CH.sub.2 --CH.sub.2 --OH; R.sub.3 =R.sub.4, and R.sub.3 and R.sub.4 are from the group --CH.sub.2 CH.sub.2 --; --CH.sub.2 --C(CH.sub.3)H--; and --C(CH.sub.3) H--CH.sub.2 --; and the diasteromeric salts thereof.

Abstract: Amines endowed with chain extension activity for formulations such as polyureas and polyurethanes are disclosed, which have the general formula: ##STR1## wherein n is 0-1000; R.sub.1 .dbd.R.sub.2, and R.sub.1 and R.sub.2 are from the group --CH.sub.2 --CH.sub.2 --; --CH.sub.2 --C(CH.sub.3)H--; and --C(CH.sub.3)H--CH.sub.2 --; and R.sub.3 and R.sub.4 are each independently selected from the group consisting of H, --CH.sub.3, --CH.sub.2 CH.sub.3, --CH.sub.2 OH, and --CH.sub.2 --CH.sub.2 --OH; and the diasteromeric salts thereof.

Abstract: The present invention relates to a novel compound tetrahydrocurcumin and a substance containing the same, which are produced from curcumin or a substance containing it as a material. This substance has characteristic properties such as strong antioxidative activity and yellowish color generated from reducing the original color of curcumin. The curcumin is being produced from a Zingiberaceae plant classified into Curcuma longa as a tropical product and is used for a spice and a yellow pigment for curry powder and pickles. The present invention further relates to the production method.

Abstract: A process for the preparation of aromatic carbonyl or sulfonyl compounds with a diaryl ether structure by reacting phenols with halogenated carbonyl- or sulfonylaromatic compounds in a dipolar aprotic solvent is carried out in the presence of catalytic amounts of alkali metal nitrite or an aromatic nitro, nitroso, azo, azoxy or hydrazo compound.

Abstract: An intermediate for the manufacture of nabumetone, 4-(6'-methoxy-2'-naphthyl)-3-buten-2-one, is prepared by contacting 2-bromo-6-methoxynaphphalene with methyl vinyl ketone in the presence of a palladium catalyst at from about 50.degree. C. to about 200.degree. C. for a time sufficient to cause substantially complete reaction to occur.

Abstract: Process for the preparation of herbicidally active substituted cyclohexan-1,3,5-triones which comprises either(a) reacting a compound of formula (II) ##STR1## wherein R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are, for example, hydrogen or C.sub.1 -C.sub.4 alkyl with a compound of formula (III):R.sup.1 COCN (III)wherein R.sup.1 is optionally substituted aryl in the presence of a base and a Lewis acid; or(b) reacting a compound of formula (VI) ##STR2## with a compound of formula (X) ##STR3## in the presence of a Lewis acid; or (c) where R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are the same, reacting a compound of formula (XI) ##STR4## with a compound of formula R.sup.3 X' in the presence of a base, wherein X' is a leaving group.

Abstract: A process for the preparation of the compound of formula (I), 3-(6'methoxy-2'-naphthylmethyl)-2,4-pentanedione, ##STR1## comprises the calalytic hydrogenation of a compound of formula (II): ##STR2##

Abstract: A process for preparing .alpha.,.alpha.-dialkoxy ketones of the formula I ##STR1## where R.sup.1 and R.sup.2 are each, independently of one another, hydrogen, C.sub.1 -C.sub.20 -alkyl, C.sub.3 -C.sub.20 -cycloalkyl, C.sub.4 -C.sub.30 -cycloalkylakyl, C.sub.9 -C.sub.30 -alkylcycloalkyl, unsubstituted or C.sub.1 -C.sub.8 -alkyl, C.sub.1 -C.sub.8 -alkoxy-, halogen-, C.sub.1 -C.sub.4 -haloalkyl-, C.sub.1 -C.sub.4 -haloalkoxy-, phenyl-, phenoxy-, halophenyl-, halophenoxy- and/or cyano-substituted aryl, C.sub.7 -C.sub.20 -aralkyl or heterocyclyl,R.sup.2 is also ##STR2## R.sup.3 and R.sup.4 are each, independently of one another, C.sub.1 -C.sub.20 -alkyl, C.sub.3 -C.sub.20 -cycloalkyl, aryl, C.sub.7 -C.sub.20 -arylalkyl, or together are an unsubstituted or C.sub.1-C.sub.4 -alkyl- substituted C.sub.2 -C.sub.7 -alkylene chain andR.sup.5 is R.sup.1 or together with R.sup.1 is an unsubstituted or C.sub.1 -C.sub.4 -alkyl-substituted C.sub.2 -C.sub.

Abstract: The invention provides a process for the preparation of fungicidally active cyclopentene derivatives of the general formula ##STR1## cyclopentane derivatives of the general formula ##STR2## and cyclohexane derivatives of the general formula ##STR3## in which n, R, R.sup.1, R.sup.2, R.sup.5, X and Y are as herein defined. Compounds of formula II and III are also provided which are useful as intermediates in the preparation of certain fungicidally active cyclopentane derivatives.

Abstract: The present invention provides a method for producing a hydroxyaromatic ketoacetal from a hydroxyaromatic methylketone. The invention further provides a method for producing a hydroxyaromatic ketoaldehyde from a hydroxyaromatic ketoacetal. The hydroxyaromatic ketoaldehyde can be further reacted to form a hydantoin, which hydantoin can be hydrolyzed to produce a hydroxyphenylglycine.

Abstract: 2-Hydroxy-4-(2'-hydroxyethoxy)phenyl aryl ketones I ##STR1## where Ar is substituted or unsubstituted aryl, are prepared by reacting 2,4-dihydroxyphenyl aryl ketones II ##STR2## with ethylene carbonate in the presence of an alkali metal or alkaline earth metal salt of a carboxylic acid as catalyst and purified with sodium dithionite.

Abstract: A process for making hexahydrolupulone is described which involves the separation of beta acids from a hop extract, the removal of catalyst poisons from the beta acids, the hydrogenation of the beta acids to hexahydrolupulone, and the purification of the resulting hexahydrolupulone. Its use as an inhibitor of the growth of unwanted types of cells is described, as well as preferred forms for such use.

Abstract: 2,2-Dimethoxy-2-phenylacetophenone is prepared by reacting benzil with dimethyl sulfate and alkali metal methylate in a nonpolar organic solvent (e.g. xylene, cyclohexane) in the presence of one or more of catalysts selected from the group consisting of polyethylene glycol, a polyethylene glycol dialkyl ether and a crown ether. The reaction can be carried out more preferably in the presence of diglyme or triglyme or a mixture of diglyme or triglyme and polyethylene glycol.

Abstract: Aromatic carbonyl compounds, in particular arylene ether ketones, are prepared by reacting an appropriate reagent system in the presence of free Lewis acid and a complex between a Lewis acid, for example, aluminum trichloride, and an inorganic salt controlling agent, for example, lithium chloride, and, optionally, a diluent, such as methylene chloride. The process is particularly advantageous for the preparation of substantially or all para-linked arylene ether ketones as the presence of the Lewis acid/Lewis base complex markedly reduces alkylation and ensures the substantial absence of ortho substitution.

Abstract: A method for producing a compound of the formula ##STR1## wherein: R.sup.1, R.sup.11 and R.sup.12 may be the same or different and each is hydrogen or alkyl;Q is methylene, --O-- or --S--;m and n are independently variable and may each have a value of 0, 1 or 2;X is hydrogen, halo, alkyl, alkylthio, alkylsulfinyl, alkylsulfonyl, hydroxy, alkoxy or trifluoromethyl;Y is hydrogen, hydroxy, alkoxy, ##STR2## --N(R.sup.1).sub.2, ##STR3## where R.sup.1 is as defined above; ring t represents a fused thiophene or fused benzene ring, said fused benzene ring optionally being substituted with a substituent Z as defined below; andZ is X as defined above, amino, alkylamino or ##STR4## {wherein R.sup.10 is hydrogen, alkyl or aryl}, comprising reacting a compound of formula II or formula III ##STR5## with a compound of the formula where Hal is a halogen; andR.sup.13 is acetyl, or Si(R.sup.14).sub.3 where each R.sup.14 independently is alkyl or aryl is disclosed.

Abstract: A process for making a hydrocarbyl vinyl ketone is disclosed. In this process a ketone having the structural formula CH.sub.3 COR, where R is lower alkyl, phenyl or C.sub.7 -C.sub.8 aralkyl, is reacted with methanol in an oxygen-containing atmosphere in the presence of a catalyst system comprising a catalytically effective amount of iron on an inert support. In another preferred embodiment, the catalyst system comprises a catalytically effective amount of a precious metal selected from the group consisting of silver and gold, in addition to iron, supported on an inert material.

Abstract: Alkoxybenzophenones of the formula (I) ##STR1## wherein R.sup.1 is C.sub.1 -C.sub.4 -alkyl and R.sup.2 and R.sup.3 independently of one another are each hydrogen, hydroxy, C.sub.1 -C.sub.8 -alkoxy, C.sub.1 -C.sub.4 -alkyl or halogen, are prepared by reacting a benzophenone of the formula (II) ##STR2## with a dialkyl sulfate of the formula (III)(R.sup.1 O).sub.2 SO.sub.2 (III)where, in the formulae, R.sup.1, R.sup.2 and R.sup.3 have the above-mentioned meanings, by a process in which the reaction is carried out in water as the reaction medium in the presence of a base, and the dialkyl sulfate (III) is added a little at a time.The process gives (I) in high yield and virtually free of 2,4-dialkoxybenzophenones.

Abstract: The present invention relates to an improved process for the preparation of 2-hydroxy-4-(hydroxyalkoxy)-benzophenone. More particularly the invention is directed to the oxyalkylation of 2,4-dihydroxy benzophenone, using C.sub.2 to C.sub.4 alkylene oxides in the presence of a basic catalyst and water. Such products are useful as ultraviolet light absorbers.

Abstract: An alpha-hydroxyl-alpha,alpha-di(inert-substituted)-gamma',delta'-yne ketone can be prepared by a procedure comprising contacting an acetylenic Grignard reagent with an alpha-hydroxyl-alpha,alpha-di(inert substituted)-alpha',beta'-ene ketone, and the alpha-hydroxyl-alpha,alpha-di(inert-substituted)-alpha',beta'-ene ketone can be prepared by a procedure comprising steps of contacting, first, an alkoxy allene with a lithium donating organic agent, second, product of the first step with a di(inert-substituted)ketone, and third, product of the second step with an acidic substance.

Abstract: A process for preparing oxocyclopentenes of the formula: ##STR1## wherein R.sup.1 is hydrogen, lower alkyl or lower alkenyl and R.sup.2 is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, substituted or unsubstituted aryl, ar(lower)alkyl, thienyl or cycloalkyl, which comprises subjecting a furan-carbinol of the formula: ##STR2## wherein R.sup.1 is as defined above and R.sup.3 is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, substituted or unsubstituted aryl, ar(lower)alkyl, thienyl or cycloalkyl to rearrangement, subjecting the resultant hydroxycyclopentenone of the formula: ##STR3## wherein R.sup.1 and R.sup.3 are each as defined above to hydrogenation and subjecting the resulting hydroxycyclopentanone of the formula; ##STR4## wherein R.sup.1 and R.sup.2 are each as defined above to dehydration.

Abstract: Symmetric and asymmetric monoacetals of aromatic 1,2-diketones are prepared by a novel process, in a nonpolar solvent in the presence of a urea derivative as the catalyst.

Abstract: According to the present invention there is provided process for preparing a compound of formula (I): ##STR1## or a salt, acylate or sulphonate derivative thereof; wherein R.sup.1 is an optionally substituted aryl group, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are selected from hydrogen, C.sub.1-4 alkyl, C.sub.1-4 alkanoyl or --CO.sub.2 R.sup.a wherein R.sup.a is C.sub.1-4 alkyl or R.sup.2 and R.sup.3 or R.sup.4 and R.sup.5 together with the carbon atom to which they are attached form a C.sub.3-6 cycloalkyl ring, provided that at least R.sub.2 and R.sup.3 or R.sup.4 and R.sup.5 are not both hydrogen and that not more than two of R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are C.sub.1-4 alkanoyl or --CO.sub.2 R.sup.a ; which process comprises reacting a compound of formula (II): ##STR2## wherein R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are as defined in relation to formula (I) with a compound of formula (III):R.sup.1 COCN (III)wherein R.sup.