SU569559A1 - Method of preparing -aminophenols - Google Patents

Description

(54) METHOD OF OBTAINING 0-AMINOPHENOLS

one

This invention relates to a process for the preparation of o-aminophenols. general formula.

 T is hydrogen or methyl, 2 and T, is an alkyl group, T and .R, together with the amino group, form a five- or six-membered cyclic amino group.

used as intermediates for fine organic synthesis, antioxidant additives to synthetic oils, motor oils, anti-aging agents, rubber, rubber and rubber, used in the manufacture of dyes, photographic paper, insecticides, detergents and drugs.

A known method for producing aminophenols by hydrogenating the corresponding nitrophenols in the presence of hydrogenation catalysts ij. The hydrogenation process is often carried out at elevated pressure, requires the use of specially prepared catalysts and additives, in this way only aminophenols with the primary amino group are obtained.

The purpose of the invention is to simplify the process.

To this end, the synthesis of o-aminophenols of the formula X is carried out by dehydrogenating the available 2-amino-substituted cyclohexen-2-one under the action of an equimolar amount of sulfur or selenium:

HE

S (Se)

R2 + H25 (H2Se) When sulfur is used, the dehydrogenation reaction is carried out at 120–200 ° C, selenium at 200–280 0. The reaction time is 10 -2 O min. The output of o-aminophenols 6O-78% of theory. O1sstekaa.1y method is of a general nature quite simple in execution and allows, depending on the structure of the taken 2-amino cyclohexenone and o-amio phenols pa3; rtfr mt3H xgteggni substitutions in the aromatic ring and the nitrogen atom, to be obtained. Example. 2-Morpholinophenol. A mixture of 5.0 g (0.0276 mol) of 2-morpholinocyclohexen-2-one and O, 89 g (0.0276 mol) of sulfur powder is heated in a metal bath at 12O-2OO C for 15 minutes. At 15 ° C – 160 ° C, an intense increase in hydrogen sulfide is observed. Upon completion of the reaction, the reaction mixture was distilled in vacuo. Get 3.6 g. {75%} o-morpholinophenol with so kip. -ISO C (15 mm Hg. Art.) T.pl. 130 ° C (alcohol). N7.8. Found, Calculated,%: N 7.81. O-morpholinophenol hydrochloride is obtained by the action of dry hydrogen chloride on its ethereal solution. T .. pl. 219-220 ° C (alcohol-ether). In the PMR spectrum of o-morpholinophenol (100 MHz, Xefi, TMS) in the region of 6.77, 2 ppm, a complex multiplication of four proton signals of 1,2 disubstituted aromatic core is observed, in which the signal of a phenolic proton is lost cycles give multiplets at 3.7-3.9 and 2.75-2.95 ppm The ratio of signal intensities is Ei: 4; 4, Example 2. 3,5-Dimethyl-2-methylaminophe. A mixture of 4.6 g (0.03 mol) of 3,5-dimethyl-2-methylaminocyclohexen-2-one and 1, O (0.03 mol) of sulfur is heated at 150-200 for 15 minutes, and the reaction mixture is distilled. in vacuum. 2.8 (62%) of 3,5-dimethyl-2-methylaminophenol are obtained. f. square 2O2-2ОЗ ° С (alcohol). Found,%: C 71.26; H 8.47 N9.45. Calculated,%: C 71.52; H 8.67; M9.2 In the PMR spectrum of 3,5-dimethyl-2-methyl phenol (100 MHz, Sce,), the signals of two-phenyl protons in the form of broadened singles are located at 6.54 and 6.34 ppm. At 2.3 and 2.24 ppm, the signals of the methyl groups are found. A two-proton singlet at 5.31 ppm corresponds to the signals of the phenol pton and the protons of the nogroup. PRI me R 3. 2-Piperidinophenol. A mixture of 4.5 g (0.025 mol) of 2-piperidino-cyclohexen-2-one and 2.0 g (0, O25 mol) of finely divided selenium is heated under reflux in a metal bath at 22O-280 C for 2O min and then the reaction mixture is distilled in vacuum. 2.7 g (6O%) of o-piperidinophenol are obtained with a bp. 10O-105 C (5 mm), so pl. 75 C (methanol) 1 Hydrochloride m.p. 173-175 ° C. Found,%: N7.90, .NO Calculated,%: N7.93; . PRI me R 4. 2-Methylaminophenol. A mixture of 7.8 g (O, O62 mol) 2-methylaminocyclohexen-2-one and 2.0 g (O, 062 mol) of sulfur is heated on a metal bath at 14 O-2OO C for 10 minutes and the mixture is distilled under vacuum. , 8 g (63%) o-methylaminophenol. Bp 95-97 C (10 mm), so pl. 96-97 C (benzene-petroleum ether). Found,%: N11.65. C Calculated,%: N11.37. Similarly, from 3.5 g (O, O25 mol) of 2-dimethylaminocyclohexenone, 2.5 g (73%) of 6 -dimethylaminophenol are obtained. Bp 8285 with (10 mm), so pl. 44-46 C (hexane). Found,%: N10.24. Calculated,%: N10,02. PRI me R 5. 2 Dimethylaminophenol A mixture of 4.2 g (O, OZ mol) 2-dimethylaminocyclohexen-2-one and 2.4 g of selenium is heated under reflux in a metal bath at 200-280 C for 20 minutes and vacuum distillation to obtain 2.1 (51%) O-dimethyl-aminophenol. Bp 73-75 ° C (5 mm), so pl. 44 ° C (hexane). Similarly, from 4.6 g iO, O25 mol) 2-morphoEHO1Shkohexenone get 2.7 g of 60%) (5-morpholinophenol. So pl. 129-13O ° C (c1 rupt). EXAMPLE 6. 2 -Di-n-butylaminophenol. A mixture of 4.5 g (0.02 mol) of 2-di-n-butylaminocyclohexen-2-one and 0.64 g (0.02 mol) of sulfur is heated at 140–200 ° C for 1O min and distillation of the reaction mixture in vacuum, obtain 2.4 g (54%) of 2-di-n-butylaminophenol. So. Bip. 130-132 ° C (5 mm), hydrochloride, t-pl. (alcohol). P p and measure 7. 2-Pyrrolidnophenol. Similarly, from 1.65 g (0.01 mol) 2-1 Schrrolidinocyclohexen-2-one and 0.32 g (0.01 mol) of sulfur get 0.97 g (59%) 2-pyrrolidinophenol. Bp. 135-137 C (3mm), mp. 1O9 -110 C (methanol). Chlorine chloride, mp 187-189 ° C (alcohol).

PMR spectrum (1OO Mga, SSE. $; TMS): 7.2-6.8 (4H, aromatic Mp (tones), 6.7O (1 N, phenolic proton / 3, 2.9 (4 N, multiplet) and 2.2-1.7 (4H, multiplet) - protons of the pyrrolioinovhot ring. Formula st. and 3 obreta and Production method - p-aminophenols of the general formula

,he

g

L2

N:

R3

where hydrogen or methyl, an alkyl group together with an amino group form a five- or six-membered cyclic amino group, characterized in that, in order to simplify the process, 2-amino-cyclohexen-2-one derivatives are dehydrated with an equimolecular amount of sulfur or selenium at 120 -28 ° C "

Sources of information, taken into account in the examination:

1. Patent of Germany No. 224О849, cl. C O7 C, publ. 14.OS. 76.