Abstract: Novel substituted 2-(1H-1,2,4-triazolyl)-1-phenylethan-1-one ketals of the general formula ##STR1## wherein one of the two phenyl substituents is in 2-position and the other is in 4-position, and wherein R.sub.a is halogen, methyl or C.sub.1 -C.sub.3 haloalkoxy, and U and V are each independently of the other C.sub.1 -C.sub.12 alkyl, unsubstituted or substituted by halogen or C.sub.1 -C.sub.6 alkoxy, or together are an alkylene bridge selected from ##STR2## wherein R.sub.1 to R.sub.5 are as defined herein, and the acid addition salts and metal complex salts, have microbicidal properties and are especially suitable for controling phytopathogenic microorganisms. They can be used in the form of plant protective or seed dressing agents for preventing or controlling plant pathogens.

Abstract: This invention encompasses compounds of Formula I ##STR1## and the pharmaceutically acceptable salts and geometrical and optical isomers thereof wherein:X, Y, and Z are each independently O or S with S optionally oxidized to S=O;Alk is straight or branched chain alkylene or hydroxyalkylene containing 1-6 carbon atoms;R.sub.1 is hydrogen or lower alkyl;n is 0 to 5;R.sub.2 is hydrogen, lower alkyl, cycloalkyl, --(CH.sub.2).sub.n --CO.sub.2 R.sub.1, phenyl, phenyl substituted with halo, lower alkyl or lower alkoxy; andAr is 5,6,7,8-tetrahydro-1-naphthalenyl, phenyl, or phenyl substituted with lower alkyl, hydroxy, lower alkoxy, or lower alkanoyl.This invention is in the field of pharmaceutical agents which act as leukotriene D.sub.4 (LTD.sub.4) antagonists and includes embodiments which act as leukotriene B.sub.4 (LTD.sub.4) antagonists.

Abstract: The present invention relates to pharmaceutical compositions containing thiodioxolane derivatives having an interesting mucolytic activity, and to a process for the preparation of said thiodioxolane derivatives of the general structural formula ##STR1## in which the carbon atom marked with an asterisk indicates a asymmetry center in the molecule,X represents an hydroxy group or --SR" and R" is hydrogen or a suitable acylic radical,R represents hydrogen, a lower alkyl, a lower hydroxy alkyl, or phenyl,R' represents a lower alkyl, a lower hydroxy alkyl, phenyl, --(CH.sub.2).sub.n SR" where n is a whole number between 1 and 3 and R" has the above indicated meaning, with condition that X and R' can never be both type of groups.

Abstract: The invention comprises antitumor compounds of the formula: ##STR1## wherein R is an alkyl group of up to 20 carbon atoms.

Abstract: 1,1-dialkoxy- or 1,1-(.alpha.,.omega.-methylenedioxy)-non-2-yn-9-ol and their OH-protected derivatives of the general formula I ##STR1## where R.sup.1 and R.sup.2 are each C.sub.1 -C.sub.6 -alkyl or together form an alkylene chain of 2 to 5 carbon atoms and X is hydrogen or a protective group which can be eliminated, their preparation and their use as intermediates.

Abstract: A process is provided for the production of a monohydroxy monocyclic acetal, e.g., trimethylolpropane cyclic formal, of a trihydroxy alcohol, e.g., trimethylolpropane, and an aldehyde, e.g., formaldehyde, by subjecting a "heavier condensation product" of the trihydroxy alcohol and the aldehyde than the desired cyclic acetal, i.e., one having a higher molecular weight and boiling point, to acetal formation conditions. In a preferred embodiment, the product of reaction of the trihydroxy alcohol and aldehyde is treated to remove the desired monohydroxy monocyclic acetal product and at least part of the remainder comprising the heavier condensation product is recycled to the reaction together with a flesh supply of trihydroxy alcohol and aldehyde. The monohydroxy monocyclic acetal product may be further reacted to obtain a desired ester, e.g. trimethylolpropane cyclic formal acrylate, such as by transesterifying the acetal with a low boiling ester of the esterifying acid, e.g.

Abstract: A process is described for preparing optically active alpha-arylalkanoic acids consisting of rearranging an optically active ketal of formula ##STR1## in which the substituents have the meaning given in the description of the invention.

Abstract: A compound of the formula ##STR1## wherein X has the formula --CR.sup.5 .dbd.CR.sup.6 --, --C.tbd.C-- or ##STR2## wherein ring A is phenyl, naphthyl or heterocyclic; wherein R.sup.1 is hydrogen, alkyl, alkanoyl or aroyl;wherein R.sup.2, R.sup.3 and R.sup.4, which may be the same or different, each is an electron withdrawing substituent of each is hydrogen or alkyl, alkoxy or dialkylamino, provided that when ring A is phenyl or naphthyl at least one of R.sup.2, R.sup.3 and R.sup.4 is an electron-withdrawing substitutent;wherein R.sup.5 and R.sup.6, each is hydrogen, halogeno or alkyl;wherein R.sup.7 is alkyl or halogenoalkyl; and wherein R.sup.8 has the formula --Y--Q--R.sup.9 wherein Y is straight- or branched-chain alkylene or alkenylene; wherein Q is --O--, --S--, --SO-- or --SO.sub.2 --; andwherein R.sup.9 is alkyl or up to 6 carbon atoms which contains one or more defined substituents, processes for their manufacture and pharmaceutical compositions containing them.

Abstract: 1,1-Dialkoxy-2-methyl-4,4-diacyloxy-2-butenes having the general structure: ##STR1## in which R.sub.1 represents alkyl substituents having from 1 to 5 carbon atoms, or both R.sub.1 substituents together represent a single ethylene or propylene substituent, or a single C.sub.1 -C.sub.2 alkyl substituent, and R.sub.2 represents alkyl substituents having from 1 to 5 carbon atoms, or cycloalkyl substituent having from 5 to 7 carbon atoms, or aromatic substituents (preferably phenyl substituents). These new compounds are useful as building blocks in the synthesis of terpenes and carotenoids.

Abstract: Compounds of the formula ##STR1## in which Y is ##STR2## X is O or S; Z is --CHOH--CH.sub.2 --CHOH--CH.sub.2 --COOH, an ester or salt thereof or the lactone thereof; andeach of R.sup.1, R.sup.2 and R.sup.3 can be alkyl, cycloalkyl; or substituted or unsubstituted phenyl; and additionally R.sup.3 can be hydrogen, are obtained by a multi-step process and are useful in the treatment of atherosclerosis, e.g. sodium(E)-7-(4-phenyl-2-isopropyl-5-phenylthien-3-yl)-3,5-dihydroxyhept-6- enoate.

Abstract: There are disclosed halogenated dioxolanes of a specified formula, dioxoles made therefrom, polymers of the dioxoles, and processes for making the dioxolanes.

Abstract: The invention encompasses compounds of Formula I ##STR1## and the pharmaceutically acceptable salts and geometrical and optical isomers thereof wherein:X, Y, and Z are each independently O or S with S optionally oxidized to S.dbd.O;Alk is alkylene or hydroxyalkylene containing 1-6 carbon atoms;R.sub.1 is hydrogen or lower alkyl;n is 0 to 5;R.sub.2 is hydrogen, lower alkyl, cycloalkyl, --(CH.sub.2).sub.n --CO.sub.2 R.sub.1, phenyl, phenyl substituted with halo, lower alkyl or lower alkoxy; andAr is 5,6,7,8-tetrahydro-1-naphthalenyl, phenyl, or phenyl substituted with lower alkyl, hydroxy, lower alkoxy, or lower alkanoyl. The compounds are useful as anti-allergy agents and anti-inflammatory agents.

Abstract: Compounds of formula I ##STR1## in conjunction with compounds that donate acid when exposed to actinic radiation, are suitable for use as positive photoresists. In formula I, R.sup.1 and R.sup.2 are hydrogen, alkyl, aryl, cycloalkyl, aralkyl or alkaryl, R.sup.3 to R.sup.8 are hydrogen or lower alkyl, X is --O-- or --NR.sup.9 --, where R.sup.9 is hydrogen or C.sub.1 -C.sub.4 alkyl n is 0 or 1, m is 2, 3 or 4 and Q is an organic radical of valency m.The photoresists are suitable for making printing formes, printed circuits, integrated circuits or silver-free photographic films.

Abstract: A process for converting 6-carboxy to 6-hydroxymethyl mevinolin analogs and novel intermediates formed in this process are disclosed.

Abstract: Derivatives of carbonyl-group containing behavior modifying compounds, in which said carbonyl group has been converted to a photolabile group which regenerates the carbonyl group on exposure to radiation, are of value in various methods for the control of animal, and in particular insect, species.

Abstract: Alkyl (6R,7S,8R)-6,9-dihydroxy-7,8-isopropylidenedioxy-2,4-nonadienoates of the formula I ##STR1## where R is alkyl of 1 to 4 carbon atoms are prepared by reacting 3,5-O-isopropylidene-D-arabinose of the formula II ##STR2## with a 3-carboalkoxyprop-2-en-1-ylidene triphenylphosphorane of the formula III ##STR3## in a solvent at elevated temperatures, by a process wherein the reaction is carried out in, as the solvent, a suitable aliphatic or aromatic hydrocarbon, a halogen derivative thereof or a cycloaliphatic ether, preferably an aromatic hydrocarbon of 6 to 8 carbon atoms, at from 65 to 130.degree. C., preferably from 80 to 115.degree. C.Using this process, the basic skeleton of d-biotin can be synthesized from D-arabinose in substantially better yields than obtainable hitherto.

Abstract: Described herein are novel monomers, polyketals derived from such monomer, improved process for the production of such monomers and a process for producing the polyketals.

Abstract: Compounds of formula I ##STR1## in conjunction with compounds that donate acid when exposed to actinic radiation, are suitable for use as positive photoresists. In formula I, R.sup.1 and R.sup.2 are hydrogen, alkyl, aryl, cycloalkyl, aralkyl or alkaryl, R.sup.3 to R.sup.8 are hydrogen or lower alkyl, X is --O-- or --NR.sup.9 --, where R.sup.9 is hydrogen or C.sub.1 -C.sub.4 alkyl, n is 0 or 1, m is 2, 3 or 4 and Q is an organic radical of valency m.The photoresists are suitable for making printing forms, printed circuits, integrated circuits or silver-free photographic films.

Abstract: The present invention relates to new asymmetric heterocyclic ester derivatives of 1,4-dihydropyridine-3,5-dicarboxylic acids of the formula: ##STR1## wherein R.sub.1 is a C.sub.1 -C.sub.4 -alkyl group; X and Y, which are identical or different, each represent O or S, at least one of the symbols X and Y being different from S; n is an integer equal to 1 or 2; and R.sub.2 and R.sub.3, which are identical or different, each represent H, CH.sub.3, CF.sub.3, C.sub.6 H.sub.5 or halogenophenyl, it being possible for R.sub.2 and R.sub.3, taken together, to form a 5-membered to 7-membered spirocycloaliphatic group with the C atom of the heterocyclic group to which they are bonded; and their optical iomers and diastereoisomers.These new derivatives are useful as pharmaceuticals, in particular as vasodilators.

Abstract: A 2,2-difluoro-2-desoxycarbohydrate is used to prepare antiviral nucleosides.

Abstract: This invention pertains to a new method for killing and controlling worms (Helminths), new formulations for killing and controlling worms in animals, new chemical compounds, and a new synthesis of northern hemisphere intermediates for the synthesis of milbemycin and avermectin macrolides.

Abstract: This invention relates to stereoisomeric forms and mixtures thereof of compounds of the formula ##STR1## having insecticidal, nematocidal, and acaricidal properties.

Abstract: Compounds of the formula I ##STR1## in which A is C.sub.2-12 -alkenyl, C.sub.4-8 -cycloalkenyl or a grouping--C(R).dbd.C(R')--Y and Y, R, R', R.sub.1, R.sub.2, R.sub.3 and R.sub.3 ' are as defined in patent claim 1, can be prepared in high yields in a simple and economical manner by reacting corresponding bromobenzenes or iodobenzenes with a compound HA in the presence of an alkali metal salt or alkaline earth metal salt of an aliphatic monocarboxylic acid having 1-12 C atoms or benzoic acid, of a cyclic or N,N-disubstituted amide as the solvent, particularly N,N-dimethylformamide, and of a palladium compound which can, if desired, contain arsenic or phosphorus, as the catalyst.

Abstract: There is presented compounds of the formula ##STR1## wherein A is selected from the group consisting of ##STR2## R.sub.1 is selected from the group consisting of hydrogen, chlorine, bromine, lower alkyl, the group NR.sub.4 R.sub.5, the group --CH.sub.2 --CO--R.sub.7, the group --NH(CH.sub.2).sub.m NR.sub.8 R.sub.9, hydroxy, lower alkoxy, mercapto and lower alkyl mercapto; R.sub.2 is selected from the group consisting of hydrogen, amino and di-lower alkyl amino; R.sub.3 is selected from the group consisting of hydrogen, lower acyloxy and hydroxy; X is selected from the group consisting of hydrogen, halogen, trifluoromethyl, ethyl, .alpha.-hydroxy ethyl and acetyl; Y is hydrogen or halogen; R.sub.4 and R.sub.5 are hydrogen or lower alkyl or together with their co-bonded nitrogen atom form a five to seven membered heterocyclic group; R.sub.7 is selected from the group consisting of hydroxy lower alkoxy and NR.sub.8 R.sub.9 ; R.sub.8 and R.sub.

Abstract: Novel processes for making arylpropionic acids are described. One process comprises carboxylating particular Grignard compounds which are the products of a catalyzed reaction between corresponding arylmagnesium bromides and ethylene. Furthermore, the reaction making the particular Grignard compounds is itself novel. Also, an improved method is disclosed for making coupled aryl compounds useful as intermediates for making compounds having a pharmaceutical use. For example, particular biaryls may be used to make some of the Grignard compounds herein from which the arylpropionic acids are made. Finally, an improved bromination is disclosed giving high yields of 4-bromo-2-fluoroaniline, which is thereafter coupled with benzene, then used to make the arylmagnesium bromide reacted with ethylene to obtain the particular Grignard compound and subsequent desired arylpropionic acid, i.e. 2-(2-fluoro-4-biphenylyl)propionic acid.

Abstract: There is presented a process for the manufacture of hexahydronaphthacene derivatives of the general formula ##STR1## wherein one of R.sup.1 and R.sup.2 represents a hydrogen atom and the other represents a hydrogen atom or a hydroxy group of R.sup.1 and R.sup.2 together represent a protected oxo group, R.sup.3 represents a hydrogen atom or a hydroxy or acyloxy group and R.sup.4 represents a lower alkyl or esterified carboxy group or a group of the formula ##STR2## wherein R.sup.5 and R.sup.6 together form an oxo group or a protected oxo group and X represents a hydrogen atom or a hydroxy or acyloxy group or ##STR3## in which n stands for 1 or 2 and Y represents a hydrogen atom or an alkyl or acyl group.Also presented are certain of the novel derivatives per se and various novel intermediates in the process.

Abstract: There is presented a process for the manufacture of hexahydronaphthacene derivatives of the general formula ##STR1## wherein one of R.sup.1 and R.sup.2 represents a hydrogen atom and the other represents a hydrogen atom or a hydroxy group or R.sup.1 and R.sup.2 together represent a protected oxo group, R.sup.3 represents a hydrogen atom or a hydroxy or acyloxy group and R.sup.4 represents a lower alkyl or esterified carboxy group or a group of the formula ##STR2## wherein R.sup.5 and R.sup.6 together form an oxo group or a protected oxo group and X represents a hydrogen atom or a hydroxy or acyloxy group or ##STR3## in which n stands for 1 or 2 and Y represents a hydrogen atom or an alkyl or acyl group.Also presented are certain of the novel derivatives per se and various novel intermediates in the process.

Abstract: A compound represented by the formula ##STR1## wherein R.sup.1 represents a lower alkyl group, a phenyl group or a benzyl group, or the two R.sup.1 groups together represent a group of the formula --CH.sub.2 --.sub.n in which n is an integer of 4 to 7; R.sup.2 represents a hydrogen atom, an alkyl group, or a substituted or unsubstituted aralkyl group; and Z represents a hydrogen atom, a lower alkyl group or a substituted or unsubstituted benzyl group;and a process for production thereof. The compounds of this invention are useful as intermediates for the synthesis of various biologically active substances, such as various antibiotics, particularly .beta.-lactam antibiotic derivatives, thienamycin, antibiotic PS-5 and their analogous substances.

Abstract: Novel chloroacetic acid cyclohexylamides of the formula I ##STR1## where R.sup.1, R.sup.2 and R.sup.3 have the meanings given in the description, their preparation and their use as herbicides.

Abstract: Processes for preparing isomerically pure 3-methylthiophene-2-carboxaldehyde, an intermediate for synthesis of anthelmintic agents, by reaction of mercaptoacetaldehyde or the dimer, or a polymer thereof, or a dialkylacetal thereof in the presence of a base with (1) methyl vinyl ketone or an alpha- or beta-oxidized derivative of methyl vinyl ketone to form a 3-oxobutylmercaptoacetaldehyde or dialkyl acetal thereof, or an alpha- or beta-substituted derivative thereof which is then converted to 3-methylthiophene-2-carboxaldehyde via appropriate steps including, if necessary, treatment with acid, followed, if necessary, by enamine catalyzed cyclization and, in the case of using methyl vinyl ketone as reactant, a dehydrogenation step; or (2) 3-butyn-2-one to produce a mixture of isomeric 3-oxobut-1-enylmercaptoacetaldehyde or dialkyl acetals thereof which is cyclized to 3-methylthiophene-2-carboxaldehyde.

Abstract: The stereospecific preparation of D(+)-biotin is improved by a synthetic route involving the conversion of 3,4-isopropylidene-D-arabinose in which the OH group in the 2-position is not protected, into an ester of 6,9-dihydroxy-7,8-isopropylidenedioxynona-2,4-dienoic acid, the latter then being catalytically hydrogenated and subsequently converted into D(+)-biotin in a manner known per se.

Abstract: The invention relates to new optically active or racemic 13-thia-prostacycline derivatives of the Formula I ##STR1## wherein R.sup.1 is hydrogen, a pharmaceutically acceptable cation or a straight or branched chain alkyl group having 1-5 carbon atoms;R.sup.2 is straight or branched chain alkyl having 4-9 carbon atoms or monosubstituted phenoxymethyl;--A--B-- is --CH.sub.2 --CH.sub.2 --, --CH.dbd.CH-- of Z-- or E-- configuration or --C.tbd.C--;one of the symbols X and Y is hydrogen, methyl or ethyl and the other is hydroxy, tetrahydropyranyoxy, 1-ethoxy-ethoxy or trialkylsilyloxy; orX and Y together form a --O--CH.sub.2 --CH.sub.2 --O-- group;Z is a sulfur atom or a --SO-- group.

Abstract: Mono-, di-, tri- and tetra-esters derived from an acid of the general formula:R--OHin which R represents an acyl radical of the general formula: ##STR1## in which n represents 0 or 1, m represents 0, 1, 2, 3 or 4, R.sub.1 and R.sub.2 each represent a straight- or branched-chain alkyl radical having from 1 to 5 carbon atoms, R.sub.3 represents hydrogen or a straight- or branched-chain alkyl radical having from 1 to 5 carbon atoms, the sum of the carbon atoms in R.sub.1 and R.sub.2 being from 4 to 10 when R.sub.3 represents hydrogen and the sum of the carbon atoms in R.sub.1, R.sub.2 and R.sub.3 being from 6 to 15 when R.sub.3 is different from hydrogen, or R.sub.1 and R.sub.2 when they are taken together represent a tetramethylene, pentamethylene or hexamethylene radical and R.sub.

Abstract: Described is a process for preparing solanone and norsolanadione using chemical intermediates defined according to the generic structure: ##STR1## wherein X is one of the moieties: ##STR2## wherein R represents hydrogen or methyl; wherein Y represents one of the structures: ##STR3## wherein one of the dashed lines represents a carbon-carbon single bond and the other of the dashed lines represents a carbon-carbon double bond; with the provisos that:(i) when Y is the moiety having the structure: ##STR4## then X is the moiety having the structure: ##STR5## (ii) when X is the moiety having the structure: ##STR6## then Y is the moiety having the structure:--C.tbd.N]In preparing solanone, the compound having the structure: ##STR7## or a mixture of compounds defined according to the structure: ##STR8## is reacted with methyl lithium and the resulting intermediate is hydrolyzed and the resulting compound is dehydrated.

Abstract: 2,2'-Bipyridinium chlorochromate has been found to be an effective oxidizing agent, particularly for the conversion of primary or secondary alcohols to their respective aldehydes or ketones.

Abstract: Bright deposits of tin and tin/lead alloys by electrocoating are obtained by using a bath containing tin salts and, optionally, lead salts, aldehydes and/or ketones as brighteners as well as surfactants besides sulfuric acid and/or borofluohydric acid wherein part or all of the aldehydes and/or ketones are replaced by a cyclic reaction product of one or more aromatic aldehydes and epihalohydrin of the general formula ##STR1## (Hal being chlorine or bromine, R being a phenyl, naphthyl or pyridyl radical which is optionally substituted by one to three members of the group consisting of chlorine, bromine or fluorine atoms, alkyl or alkoxy groups having 1 to 3 carbon atoms, carboxy and hydroxy groups). Preferably the cyclic reaction product is contained in the bath in an amount of from 0.1 to 2 g/liter of the bath.

Abstract: Unsymmetrical bis-carbamates of the formula ##STR1## wherein R.sub.1 is a phenyl, dihydrobenzofuranyl, naphthyl, pyrimidyl, pyrazolyl, triazolyl, quinolinyl or tetrahydroquinolinyl group, andR.sub.2 is a benzyl group,processes for producing them and their use for combating pests are described.

Abstract: In a process for the preparation of an aromatic chloroformic acid ester by contacting a phenol and phosgene, the improvement wherein the reaction is carried out in a homogeneous liquid phase at a temperature of 60.degree. to 180.degree. C. in the presence of organic phosphorus compound of the formulaR.sup.1 R.sup.2 R.sup.3 PR.sup.4.sub.n X.sub.nin whichR.sup.1, R.sup.2 and R.sup.3 independently of one another represent hydrogen, alkyl, alkenyl, aralkyl, aryl or halogen and two of the said radicals together with the phosphorus atom can form a 5-membered or 6-membered phosphorus-containing saturated or unsaturated heterocyclic radical,X represents OH, homopolar-bonded halogen or an inorganic or organic acid anion,R.sup.4 denotes hydrogen or alkyl or, if X denotes halogen, can also denote halogen and n denotes 0 or 1,and in which, furthermore,R.sup.4 and X together can represent oxygen or sulfur.

Abstract: The object of the present invention is a novel and simple process for the production of 1,2-diacyl-sn-glycerols, wherein the acyl groups may be the same or different. According to the invention D-mannitol is reacted with benzene boronic acid or a derivative thereof to form a D-mannitol-monobenzeneboronate which compound is acylated either to form, after removal of the benzeneboronate protective group, a 1,2,5,6-tetraacyl-D-mannitol with four identical acyl groups, or is acylated selectively in two stages, by first acylating the 1,6-hydroxy groups of the boronate protected D-mannitol to form, after removal of the boronate protection, a 1,6-diacyl-D-mannitol, which then is repeatedly reacted with a benzene boronic acid or a derivative thereof and then acylated in the 2- and 5-positions.

Abstract: A process for the preparation of a 1,1-dichloroalkene of the formula ##STR1## in which R.sup.1 is hydrogen, or an optionally substituted alkyl, alkenyl, alkinyl, cycloalkyl, aralkyl, aralkenyl or aryl radical, andR.sup.2 is an optionally substituted alkyl, alkenyl, alkinyl, cycloalkyl, aralkyl, aralkenyl or aryl radical, orR.sup.1 and R.sup.2 together form an optionally branched and/or optionally benzo-fused hydrocarbon chain,comprising reacting a carbonyl compound of the formula ##STR2## with a trichloromethanephosphonic acid ester of the formula ##STR3## in which R.sup.3 each individually is an alkyl or phenyl radical, or the two radicals R.sup.3 together are alkanediyl,in the presence of at least an equimolar amount of a phosphorous acid triamide of the formulaP(NR.sup.4.sub.2).sub.3in whichR.sup.4 each independently is an alkyl radical, or the two radicals R.sup.4 together are alkanediyl.Advantageously,R.sup.1 is hydrogen,R.sup.2 a C.sub.2 to C.sub.

Abstract: Compounds of the formula I ##STR1## in which p, m, Z, R, R' and Y are as defined in claim 1, can be obtained in a simple and economical manner by a novel process which comprises reacting a halide of the formula ##STR2## with the corresponding acrylic acid derivative, in the presence of a base and of certain palladium catalysts, such as palladium acetate. The compounds (I), and functional derivatives prepared therefrom, are useful for the preparation of photocrosslinkable polymers, which can in particular be employed as (so-called) photoresists.