IL43407A - Preparation of pyrocatechol monoethers - Google Patents

Abstract

1457108 Preparation of pyrocatechol derivatives BASF AG 24 Oct 1973 [25 Oct 1972] 49404/73 Heading C2C Pyrocatechols ethers of formula where R denotes alkyl which may be substituted by halogen, alkenyl which may be substituted by halogen, alkynyl which may be substituted by halogen, or aralkyl are obtained by cleaving in an acid medium a compound of formula where R has the above meaning and R<SP>1</SP> denotes H or (C 1-4 ) alkyl; R<SP>2</SP> denotes H, benzyl, (C 1-4 ) alkyl which may be substituted with halogen, -OCH 3 or -OC 2 H 5 ; R<SP>3</SP> denotes (C 1-4 ) alkyl, cycloalkyl, #-chloroethyl, alkoxyalkyl, phenyl, (C 2-4 ) alkenyl, (C 2-4 ) alkynyl, or acyl or R<SP>1</SP> and R<SP>2</SP>, together with the carbon atoms whose substituents they are, and R<SP>1</SP> and R<SP>3</SP>, together with the carbon and oxygen atom whose substituents they are, form a 5- or 6-membered ring. The invention also comprises compounds of Formula II wherein R, R<SP>1</SP>, R<SP>2</SP> and R<SP>3</SP> have the meanings given above with the proviso that when R is methyl, R<SP>1</SP> and R<SP>2</SP> are not simultaneously hydrogen. [GB1457108A]

Description

Preparation of pyrocaechol monoethers BASF ATIENGBSELLSCHAPT Ci 41578 43407/'' 3 The. present invention relates to a new and valuable process for the preparation of pyrocatechol monoethers.

It is known to produce pyrocatechol derivatives, especially pyrocatechol ethers, by the following processes: partial etheri fication of pyrocatechol (cf.J.Chem. Soc. , 1927, 1664; U.S. Patent 3, 202, 573 ) ; diazbtization of o-aminophenylalkyl ethers (German Published Application DAS 1 , 5^3 , 573; and dehydrogenation of monoenol ethers of 1 , 2-cyclohexanedione with sulfur at reaction temperatures of from 200° to 300°C (German Laid-Open Application DOS 1 , 917, 602 ) : The disadvantage of the process employing pyrocatechol as starting material is that pyrocatechol and alkylating agent are lost due to the formation of bis-ethers. The other two processes are in part technically elaborate, often multi-stage syntheses with attendant air and effluent pollution problems. The prior art processes are unsuitable particularly when secondary reactions (ring closure or rearrangement reactions) take place under the reaction conditions as a result of reactive radicals R.

We have now found that valuable pyrocatechol ethers of the formula where R denotes alkyl which may be substituted by halogen, alkenyl which may be substituted by halogen, alkynyl which may be substituted by halogen, or aralkyl, are obtained in a simple manner and in excellent yields when a pyrocatechol derivative of the formula alky1 (C^ to C^), R denotes hydrogen, lower alkyl (C1 to C^) ^ which may be substituted by halogen (CI, Br, I )j methoxy or ethoxy, 2 3 or R denotes benzyl, R denotes alkyl (C^ to C^), cycloalkyl (C^ to :C^) , p-chloroethyl, alkoxyalkyl (methoxyethyl, ethoxyethyl), alkenyl.(up to C ) , alkynyl (UD to Cj, lower alkanoyl (acetyl) 4 ' 4 1 2 or phenyl, and R and R , together with the carbon atom. whose substituents they are, and R 1 and R3 , together with the carbon and oxygen atom whose substituents they are, denote a 5- or 6- 'membered saturated ring (cyclonentyl, cyclohexyl, tetrahydrofuronyl , tetrahydropyranyl) , is cleaved in a dilute acid medium, e.g., bv the action of aqueous acid or by an exchange reaction with lower (C, ,to C ) alcohols or nhenols with acid catalysis.

The reaction is illustrated for example' by the following eouation: For instance, the starting materials are stirred, preferably at a temperature of from 40° to 100°C, in very dilute, e.g. 0.001$ (by weight) aqueous mineral acid, e.g. ^SO^, HC1, HNO^, H^PO^, until cleavage is over. If necessary, water-miscible solvents (e.g. alcohols, ketones and ethers) for increasing the solubility of the start ing compounds may be added to the mixture in amounts of from 0.1 to 90$ (by weight).

The pyrocatechol monoethers prepared in this manner and having the following formula: are given below: CH^ b. p. ( 25 mm) : 105 C C2H5 b.p. (20 mm): 100°C n-C^H^ b.p. (14 mm): 1 10° to l l 4°C · i-C^H^ b.p. (0. 2 mm): 66°C -CH2-CH=CH2 ' b.p. ( 12 mm ) : 110°C -CH2-CH=CH-CH^ -CH2-CH=CC1-CH5 n^5: 1 , 4875 -CH2-C=CC12 n^5: 1 , 5027 CH^ -CH2-C≡CH m.p.: 49° to 50°C 47°C 2°C The new process is illustrated by the following examples.

EXAMPLE 1 o- ( 1 -butyn- -yloxy ) -phenol 220 parts by weight of o- (l-methoxyethoxy)-phenyl- ( 1 ' -butyn-3 ' -yl) ether is slowly dripped into a well-stirred mixture, boiling under reflux, of 2, 000' parts by weight of water, 500 parts by weight of ethanol and 2 parts by weight of concentrated sulfuric acid. The whole is then stirred for a further 2 hours under reflux and subsequently allowed to cool. Extraction is then carried out > times, eac time with 150 parts by weight of chloroform. After drying over Na2S0 the solvent is evaporated off, and the oil which remains crystallize after having been allowed to stand for a short period of time. Thin-layer chromatography shows the substance. to be uniform. o-isopropoxyphenol Adopting the procedure described in Example 1 , 209 parts by^ weight of .o-(l-methoxyethoxy)-phenyl isopropyl ether is hydrolyzed.

Yield: l 49 parts by weight; b.p. (0. 2 mm): 66°C.

EXAMPLE 5 pyrocatechol mono- ( 1 -buten-3-yl ) ether Adopting the procedure described in Example 1 , 222 parts by weight of o- (l-methoxyethoxy)-phenyl ( 1 ' -buten-3 * -yl )/ether is hydr ly zed.

Yield: 152 parts by weight; b.p. (0. 4 mm): 68° to, 74°C.

EXAMPLE 4 pyrocatechol mono- ( 1 -propyn-3-yl )■ ether Adopting the procedure described in Example 1 , 206 parts by weight of o-(l-methoxy)-phenyl. (l-propyn-^-yl ) ether is hydrolyzed. Yield: 140 parts by weight; m.p. : 49° to 50°C.

EXAMPLE 5 pyrocatechol mono- ( 2-butyn-4-yl ) ether Adopting the procedure described in Example 1 , 1 10 parts by weight of o-(l-methoxyethoxy)-phenyl ( 2 ' -butyn-4 ' -yl) ether is hydr ly zed . . .

Yield: 77..parts by weight; m.p.: 44° to 47°C The compounds are important intermediates for pharmaceutical products and products for use in veterinary medicine, and for the production of active ingredients for plant protection agents.

The prior art active ingredients "for use in plant protection agents are prepared by known methods, e.g., reaction of pyrocatecho ether with methyl isocyanate. For instance, the reaction of o-isopropoxyphenol \i with methyl isocyanate yields o-isopropoxyphenyl N-methylcarbamate, a well-known insecticidal active ingredient.

The pyrocatechol bis-ethers used as starting materials are obtained by reacting, in the presence of bases, pyrocatechol with a 4 "¾ vinyl ether of the formula R 0Ry, where R denotes vinyl which may "be substituted by lower alkyl and R β-chloroethyl, alkoxyalkyl, lower a alkanoyl or phenyl, or with an cx-haloether of the formula ;·.?.! C-OF ? .. where hal denotes 01, Br or I, R1 denotes hydrogen or lower alkyl, R denotes hydrogen, benzyl, or lower alkyl which may be sub- . ' 3 stituted by halogen, methoxy or ethoxy, and R denotes lower alkyl, cycloalkyl," p-chloroethyl, alkoxyalkyl, lower alkenyl, lower . alkynyl, lower alkanoyl or phenyl, any bis-ethers of the formula 1 2- where R , R and have the above meanings, which may have formed being reacted with pyrocatechol, and by treating the reaction product of the formula . where R , R and R^ have the above meanings, with alkylating agents RX, such as alkyl sulfates, alkyl aryljsulfonates, or alkyl alkenyl mono ' ' and alkynyl/halides having linear or branched alkyl radicals which may be substituted by halogen (Cl, Br, I), or with aralkyl halides (benzyl) in an alkaline medium in accordance with the following equation: be substituted by a ogen , r, , or eno es ara y .

X denotes a halogen atom (CI, Br. I), or an alkoxysulfonyloxy or . ' arylsulfonyloxy group.

The alkylation conditions (temperature, pressure, solvents and base) are the same as in conventional ether syntheses (cf. Houben- Weyl, Methoden der organischen Chemie, 6/3, p. 83). To carry out the following reaction, e.g., OCH^ the sodium salt in its hydrated or dehydrated form, e.g., in aceto- nitrile or dimethyl^formamide, is heated under reflux with a slight excess of l-butyn-3-yl chloride until the solution shows a neutral reaction. Etherificatlon proceeds with good yields.

Examples of other analogous pyrocatechol derivatives are given below: R1 R2 R? « b. • P. °C H H CH, 1 -C,Hr» 0.1 mm: 82 to 85 3 3 7 H H CH5 03 -CH C¾ 0.1 mm: 100 to 1 C≡CH H . H -CH^CH3 0.1 mm: 104 to 106 C2H5 C=CH H CH3 i-C^ 0.2 mm: 60 to 66 CH3 H CH, CH, -CH 0.2 mm : 100 to 110 3 3 ^CH R1 R2 R* b • P. °C H C¾ CH -CH2-C=CH 0. 3 mm: 100 to 102 H CH, CH, -CH„-CH=CH-CH, 3 3 H CH 0. 2 mm: 130 to 150 The following examples demonstrate the preparation of the ethers.

EXAMPLE 6a o-(l-methoxyethoxy)-phenol, · sodium salt · 3 HgO In an Erlenmeyer flask 200 parts by weight of 20$ (by weight) aqueous caustic solution is added, under nitrogen, to 168 parts by weight of o-(l-methoxyethoxy)-phenol. The mixture is briefly shaken and allowed to stand for 1 hour at room temperature. The crystalline slurry is suction filtered and washed with a mixture of ether and isopropanol (weight ratio 1 : 1 ) . The product is practically colorless, and melts^ at 72° to 73°C The yield is 80 to 90$ of theory.

The water of crystallization may be easily removed under a water jet vacuum at from 70° to 1 10°C.

Analysis: (2 ) C H Na Calc.: 44. 3 7. 0 9 . 4 Found: 43. 8 7. 0 9 . 0 EXAMPLE 6b o-(l-methoxyethoxy)-phenyl/(l ' -butyn-3 ' -yl)/ether 244 parts by weight of the sodium salt of o- ( 1-methoxyethoxy )-phenol containing 3 molecules of water of crystallization, or 190 g of dehydrated salt is suspended in 300 parts by weight of dimethyl formamide. The mixture is heated to the boil while stirring and then is removed by suction filtration. The filtrate is up in 1 , 000 parts of benzene and throughly washed with 500 ml of 2N caustic soda solution. After drying over has been effected the solvent is evaporated. Distillation is carried • ful^ ' out after the addition of a spatula tip/of succinic acid.

Yield: 182 parts by weight; b.p. ( 0. 2 mm): 100° to 110°C.

Analysis: C-^H^O^ ( 220 ) C H ..

Calc: 7Ο .9 7.5 Found: 70. 5 7. 5 EXAMPLE o- (1-methoxyethoxy) -phenyl isopropyl ether The procedure of Example 6 is adopted except that 150 parts by weight of isopropyl bromide is used instead of l-butyn-3-yl chloride B.p. (0.2 mm): 60° to 66°C.

EXAMPLE 8 o-( 1-methoxyethox ) -phenyl (1 ' -buten- ' -yl ) · ether The procedure of Example 6 is adopted except that 110 parts by weight of l-buten-3-yl chloride is used instead of l-butyn-3-yl chlo ride.

B.p. (0.3 mm): 80° to 91°C Analysis: (222) · • C H Calc: 70.3 8.1 Found: 70.4 8.3 EXAMPLE 9 o- l-ethoxyethoxy)-phenylr(l ' -butyn-3 ' -yl) ether 0 parts by weight of pyrocatechol is dissolved in 1 , 500 parts of tetrahydrofuran. 1 ml of concentrated hydrochloric acid is added and 30 parts by weight of vinyl ethyl ether is then dripped in.. The mixture is then kept for 1 hour at 65°C and subsequently allowed to cool. There is added 20 parts by weight of a 30 wt technical grade is then added and the mixture heated under reflux until it neutral reaction.- Precipitated sodium chloride is filtered the filtrate concentrated. The oil remaining. is dissolved in 3,000 parts of benzene and washed times, each time with 1,000 parts of 2N aqueous NaOH. Drying is subsequently carried out over Na2S0^. The solvent is evaporated off and . distillation effected after the addition of 2 parts by weight of succinic acid.

Boiling point (0.2 mm): 100° to 111°C Analysis: C^H^O^ (2}~K) .

C H calc. : 71.8 \ 7.7 found : 70.6 . 8.0 EXAMPLE 10 o- (l-methoxyethoxy)-phenyl benzyl ether The procedure of Example is adopted except that \ > > parts by weight of benzyl chloride is used instead of l-butyn-3-yl chloride. The mixture is heated under reflux until it shows a neutral reaction Yield: 175 parts by weight; boiling point. (0.2 mm): 1^0° to 150°C.

The pyrocatechol may be etherified for instance by reacting it with the amount necessary for etherifying an OH group of pyrocatecho or with up to 50$ more or less the molar amount, of a vinyl ether of the formula . ' R-O-R5 , where R denotes vinyl or vinyl substituted by lower alkyl (up to 3 carbon atoms) and R^ denotes alkyl ( C^ to C^), cycloalkyl (C^ to C^) β-c (up to the add aving an acid reaction, for instance mineral acids, acid salts, organic acids, oC-halo ethers, and organic and inorganic acid chlorides, and ion exchan ers and Lewis acids e. . AlCl FeCl BF etc. Etheri- and with or without the addition of solvents or diluents (e.g. 5 to 80 wt ), e.g. ethers (diethyl ether/ tetrahydrofuran, dioxane), hydr carbons (e.g. n-hexane, benzene, toluene, xylene) and halohydrocarbo (CH2C12, CHCl CCl^), which are inert to the reactants.

When pyrocatechol is reacted with vinyljmethyl ether, the reaction may be represented by the following equation: The catalysts used are preferably those mentioned above.

The pyrocatechol ethers may also be prepared by reaction of pre 0 ferably equimolar amounts or with up to approx. 50 more or less the molar amount of οί-halo ethers of the formula R1 hal-C-OR^ where hal denotes CI, Br and I, denotes hydrogen or lower alkyl (C^ to C^), denotes hydrogen unsubstituted or halogen (Cl,Br,I)-substituted, methoxy-substituted or ethoxy-substituted lower alkyl (C^ to C^.) or benzyl, and R denotes alkyl (C^ to C^ ) , cycloalkyl (C^ to C^) , β-chloroethyl, alkoxyalkyl (methoxyethyl , ethoxyethyl) , alkenyl (up to C^), alkynyl (up to C^), lower alkanoyl (acetyl), and phenyl and R1 2 and R together with the carbon atom whose substituents they are, and further R1 and R3 together with the carbon atom and oxygen atom · respectively whose substituents they are, denote 5- or 6-membered saturated ring (cyclopentyl ., cyclohexyl, tetrahydrofuranyl, tetrahydro-pyranyl) with salts of pyrocatechol or with pyrocatechol in the presence of preferably equimolar amounts of organic of inorganic bases (e.g. alcoholates, alkali metal and alkaline earth metal hydroxides, and suitable amines) or of substances having an alkaline action, for instance The radicals R , R and R-^ have the meanings given above. The reactants are preferably diluted, e.g. with 5 to 80 wt$ of ether (diethyl ether, tetrahydrofuran) or hydrocarbons (n-hexane, benzen toluene, xylene).

The vinyl and θ( -halo ethers used for the reaction are known from the literature and are simple to manufacture on an industrial J.Liebig's scale (cf., for example, W. Reppe et Άΐ,γΑήη.' Chem., 601 , 9&, 1956 Depending on the excess amounts of vinyl and o6-halo ethers us in the above processes, corresponding amounts of bis-ethers of the formula R , R and having the above meanings, are formed. .

The bis-ethers may .be produced in quantitative yield preferab by reaction of pyrocatechol with at least twice the molar amount o a vinyl ether.

The catalysts and reaction conditions are similar to those em ployed in the preparation of compounds of the' formula I.

Compounds of the formula I may also be prepared by reacting a bis-ether of the formula II with pyrocatechol in accordance with t following equation: . . , 1 2 Ί The radicals R , R and R , the catalysts and the reaction conditions are the same as in the preparation of compounds of the formula I from vinyl ethers.

The pyrocatechol derivatives of formulae I and II are obtained as colorless oils which, after having been stabilized with organic or inorganic bases, may be distilled in vacuo without decomposition occurring. The compounds are listed below: formula I; H H CH b.p. (0.4 mm) : 89 to 9 H H b.p. (0.1 mm ) : 90 to 100 C2H5 H CH5 CH3 b.p. (0.5 mm) : 85 to 90 H CH^ ¾¾ b.p. (1 mm ) : 78 to 81 H CH, η-C-zHr» b.p. (1 mm): 96 to 98 3 7 H CH^ i-C5H7 b.p. ( 1 mm ) ; 89 to 94 H CH5 i-C^ b.p. (0.2 mm) : 94 to 98 H CH, b.p. (0.2 mm) : 128 to 1 5 H CH, ■o b.p. (4 mm ) s 132 to 136 H CH^ —CH ~CH=CH H CH^ -CH2-C≡CH /CH, H CH -CH 5 ^C≡CH H CH^ -CH2-CH2-OCH;5 H CH, -CH -CH -0C Hp- H CH.

C2H5 (1.5 mm): 105 to 11 H C2H5 C2H5 (0.5 mm): 100 to 10 H CH2-C=CH C2H5 H CH2-CH2C1 CH. nji : I.5023 H CH_-CHC1-CH, CH- 2 3 H CH2-CHBr-CH^ CH.

H CH2-CHC1-C2H5 CH-H n"¾H7 . CH- CH, CH, CH- CH, CH2C1 C2H5 CH, CH2Br CH-.

CH, CH2Br C2H5 CH- C2H5 CH, CH- CH- 1-¾Η7 CH, . . , formula II: H H CH. b.p. (0.4 mm) : 105 to 109 H CH- CH- b.p. (Ό. 5 mm): 99 to 105 H CH, b.p. (0. 3 mm): 97 to 102 C2H5 H CH, i _c H9 b.p. (0. 3 mm) : 124 to 128 EXAMPLE 11 a o- ( 1-methoxyethoxy) -phenol 110 parts by weight of pyrocatechol is suspended in 100 parts by weight of toluene. At +5°C, 64 parts by weight of viny^'methyl ether at -40°C is introduced all at once into the suspension and a drop of concentrated hydrochloric acid is then added. The mixture is heated, with stirring, to about +20°C, whereupon the reaction is initiated and the temperature in the flask rises to about 65°C. If necessary, ice water may be used for external cooling. The mixture is kept for 30 minutes at 65°C and 5 parts by weight of 2N NaOH is then added. After the mixture has been cooled and dried with NagSO^ the solvent is evaporated in a rotary evaporator and distillation carried out in vacuo.

Yield: 155 ' parts by weight; b.p. ( 0. 5 mm): 85° to 90°C.

Analysis: C^H^O^ ( 168 ) C H calc: 64. 1 7. 2 found: 64.4 , 7. 0 EXAMPLE lib tion that twice the amount ( 128 parts by weight) of vinylmethyl ether is used, 122 parts by. weight of a colorless oil is obtained.

Boiling point (0. 5 mm): 99° ■ to 105°C.

Analysis: C^H^O^ ( 226 ) C H calc.: 6^ . 7 8. 0 found: 63. 3 8. 1 EXAMPLE 1 1 c o- ( 1-methoxyethoxy) -phenol At 0°C, 0. 5 part of SOClg is added to 113 parts by weight of pyrooatechol bis- ~( 1-methoxy)-ethyl) e hexg and 5 parts by weight of pyrooatechol and the mixture stirred for 30 minutes at this tem-perature. The mixture is cooled, 2 ml of 25 wt$ aqueous NaOH solution is added, the product is separated and dried over Na'gSO^ and the solvent evaporated.

Yield: 168 parts; b.p. (0. 5 mm): 85° to 90°C.

EXAMPLE 12a o- ( 1 -ethoxyethoxy) -phenol 220 parts by weight of pyrooatechol is suspended in 200 parts by weight of toluene, 2 drops of concentrated hydrochloric acid are added and then, while stirring, 150 parts by weight of ethyl vinyl ether is dripped in. The internal temperature is prevented from rising above 65°C by external cooling with ice water. Upon conclusion of the reaction all the pyrooatechol has dissolved. 5 parts by weight of 2N NaOH is added to the mixture which is then allowed to cool. The product is dried over NagSO^ and, after removal of the solvent, distilled in vacuo.

Yield: almost quantitative; b.p. ( 1 mm): 780 to 8l°C.

Analysis: C^H^O^ ( 182 ) C H EXAMPLE 12b pyrocatechol bis-^(l -ethoxy) -ethyl] etherj-L If 300 parts by weight of ethyl vinyl ether is used instead of 150 parts, 248 parts by weight of a colorless oil is obtained.

Boiling point (0.5 mm); 97° to 102°C.

Analysis; C^HggO^ ( 5 ) C H calc. : 66. 2 8. 6 found ; 66. 8. 7 EXAMPLE 12c o- ( 1 -ethoxyethoxy)-phenol 127 parts by weight of pyrocatechol bis-/~(l-ethoxy) and 55 parts by weight of pyrocatechol are reacted and the mixture worked up as in Example 11 c .

Yield; 179 partsj b.p. ( 1 mm): 79° to 80°C.

EXAMPLE 13 o- (methoxymethox ) -phenol 110 parts by weight of pyrocatechol is dissolved in 400 parts by weight of benzene. At room temperature there are simultaneously dripped into this solution 101 parts by weight of triethylamine and 8l parts by weight of chloromethyl methyl ether in such a manner that the reaction medium has a weakly alkaline reaction. Subsequently the mixture is heated for an hour under reflux and then allowed to cool. The hydrochloride is removed by suction filtration and the product is washed, dried over a2S0^, concentrated and distilled in vacuo .

Yield; 120 parts by weight; b.p. (0. 4 mm): 89°C; nj[p: 1 . 5150 Analysis: ( 154 ) C H calc. : 62. 3 6. 5 found: 62. 0 6. 5 . . , It is thus possible to produce pyrocatechol monoethers via the intermediate of the formula III R, R , R^ and R^ having the above meanings, from pyrocatechol in a simple manner and with up to quantitative yields; the reactions may also be carried out in a single vessel.

Claims (2)

' 43407/2 What we claim is:

1. A process for producing a pyrocatechol ether of the fo£ u where R denotes alkyl which may be substituted by halogen, alkeny which may be substituted by halogen, alkynyl which may be substit by halogen, or aralkyl, wherein a pyrocatechol derivative of the mula where R has the above meanings, R denotes hydrogen or lower alkyl, 2 denotes hydrogen, enzyl, or lower alkyl which may be substituted 3 by halogen, methoxy or ethoxy, R denotes lower alkyl, cycloalkyl, β-chloroethyl, alkoxyalkyl, lower alkenyl, lower alkynyl, lower 1 2 alkanoyl or phenyl, R and R together with the carbon atom, whose substituents they are, and R 1 and R3 together with the carbon atom and the oxygen atom whose substituents they are denote a 5- or 6- dilute membered saturated ring, is cleaved in ε../ acid medium.

2. A process as claimed in claim 1 wherein pyrocatechol is r acted, in the presence of a base, with a vinyl ether of the formu R¾R^, - where R^denotes vinyl which may be substituted by lower alk and ^ has the meanings given for it in claim 1, or with an oi-ha ether of the formula R1 hal-C-OR^ where hal denotes chloro, bromo or iodo and R , R and R-^ having meanings given in claim 1, any bis-ether which may have formed of the formula O.Z. 29, 85 ♦· where R , R and R-^ have the above meanings, is reacted with pyro-catechol and the reaction product of the formula where R 1 , R2 and have the above meanings, is reacted with an alkylating agent of the formula RX, where R denotes alkyl which may be substituted by halogen, alkenyl which may be substituted by halogen, or alkynyl which may be substituted by halogen, or aralkyl and X denotes halide, alkoxy, sulfonyl or arylsulfonyl, and the dilute product of alkylation is cleaved in am 'acid medium. Applicants D COHN